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diff --git a/40005-8.txt b/40005-8.txt deleted file mode 100644 index 0bca630..0000000 --- a/40005-8.txt +++ /dev/null @@ -1,11918 +0,0 @@ -The Project Gutenberg EBook of North American Recent Soft-shelled Turtles -(Family Trionychidae), by Robert G. Webb - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - - -Title: North American Recent Soft-shelled Turtles (Family Trionychidae) - -Author: Robert G. Webb - -Release Date: June 16, 2012 [EBook #40005] - -Language: English - -Character set encoding: ISO-8859-1 - -*** START OF THIS PROJECT GUTENBERG EBOOK NORTH AMERICAN RECENT *** - - - - -Produced by Chris Curnow, Tom Cosmas, Joseph Cooper, page -images courtesy of The Internet Archive and the Online -Distributed Proofreading Team at http://www.pgdp.net - - - - - - - -Transcriber's Notes - - Mathematical Notation - - 1) _{#} for subscripted number or character and - ^{#} for superscripted number or character - Example: Carbonate Ion = CO_{3}^{--} - - 2) Whole and fractional number: 7-2/3 - - Text Emphasis - - Italic words displayed as _Text_ and bold as =Text=. - - - - -UNIVERSITY OF KANSAS PUBLICATIONS - -MUSEUM OF NATURAL HISTORY - - -Volume 13, No. 10, pp. 429-611, pls. 31-54, 24 figs. - -February 16, 1962 - - - - -North American Recent Soft-shelled Turtles - -(Family Trionychidae) - - -BY - - -ROBERT G. WEBB - - - - -UNIVERSITY OF KANSAS - -LAWRENCE - -1962 - - -UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY - -Editors: E. Raymond Hall, Chairman, Henry S. Fitch, Robert W. Wilson - - -Volume 13, No. 10, pp. 429-611, pls. 31-54, 24 figs. - -Published February 16, 1962 - - -UNIVERSITY OF KANSAS - -Lawrence, Kansas - - -PRINTED IN - -THE STATE PRINTING PLANT - -TOPEKA, KANSAS - -1962 - -[Illustration (Union Label)] - -28-7818 - - - - - -North American Recent Soft-shelled Turtles - -(Family Trionychidae) - - -BY - - -ROBERT G. WEBB - - - - -CONTENTS - - - PAGE - - CONTENTS 431 - - INTRODUCTION 433 - Collecting Methods 434 - Materials and Procedure 437 - Acknowledgments 439 - - TAXONOMY 439 - Family Trionychidae Bell, 1828 439 - Genus _Trionyx_ Geoffroy, 1809 443 - Variation 445 - Secondary Sexual Variation 446 - Ontogenetic Variation 449 - Geographic Variation 453 - Character Analysis 460 - Composition of the Genus _Trionyx_ in North America 476 - Artificial Key to North American Species and Subspecies - of the Genus _Trionyx_ 476 - Systematic Account of Species and Subspecies 479 - _Trionyx ferox_ 479 - _Trionyx spinifer_ 486 - _Trionyx spinifer spinifer_ 489 - _Trionyx spinifer hartwegi_ 497 - _Trionyx spinifer asper_ 502 - _Trionyx spinifer emoryi_ 510 - _Trionyx spinifer guadalupensis_ 517 - _Trionyx spinifer pallidus_ 522 - _Trionyx ater_ 528 - _Trionyx muticus_ 531 - _Trionyx muticus muticus_ 534 - _Trionyx muticus calvatus_ 539 - - NATURAL HISTORY 541 - Habitat 541 - Daily and Seasonal Activity 547 - Diurnal Habits 547 - Behavior Adaptations 549 - Movement 552 - Nocturnal Habits 553 - Seasonal Occurrence 553 - Food Habits 555 - Reproduction 558 - Size of Males at Sexual Maturity 558 - Size of Females at Sexual Maturity 560 - Sexual Activity 563 - Deposition of Eggs 565 - Reproductive Potential 568 - Eggs 572 - Incubation and Hatching 573 - Age and Growth 574 - Mortality 576 - Parasites 576 - Economic Importance 577 - - EVOLUTIONARY HISTORY 578 - Distribution 578 - Relationships 579 - Fossils 582 - Phylogeny 585 - The Importance of the Study of Turtle Populations in - Relation to the History of River Systems 588 - - SUMMARY 590 - - LITERATURE CITED 594 - - - - -INTRODUCTION - - -Is it true that the greater the degree of resemblance between two -populations the shorter the time the two have been spatially isolated? -Are aquatic environments more stable than terrestrial environments? -These questions occurred to me while I was collecting turtles from river -systems of the Gulf Coast. As a general rule, each kind of turtle seemed -to occur throughout one continuous river system or large tributary, and -with no barriers to dispersal therein and with the lapse of enough time -for a population to reach its limits of dispersal, the question arose, -"Where do subspecies and zones of intergradation occur?" It seemed -logical to think that each isolated and continuous aquatic environment -would not contain more than one subspecies of the same species. In -terrestrial environments subspecies and transitions between them were -recognizable. Terrestrial habitats were continuous for longer distances -than the isolated, aquatic habitats. But, different species of turtles -prefer different kinds of aquatic habitats. Also, barriers occur in -large drainage systems, such as the Mississippi, where, in general, -the western tributaries are sluggish, turbid and shallow, and the -eastern tributaries are fast-flowing, clear and deep. But in young, -relatively small, river systems that do not traverse radically different -physiographic regions, and that show no gross ecological differences, -habitats or microhabitats that do exist probably are only partial -barriers and seem not to prevent the dispersal of most kinds of aquatic -turtles. Consequently, it seemed that study of the degree of difference -between closely related populations of turtles that occurred in one -drainage system, or in adjacent drainage systems would indicate the -length of time, respectively, that the drainage system had been -continuous or the length of time that two or more systems had been -isolated from one another. - -Rivers or series of river systems having endemic kinds of turtles or -having the most kinds of turtles that are different from those in -adjacent rivers may be the oldest geologically, or may have been -isolated the longest. Knowledge of the kinds of turtles and their -relationships and distribution could indicate chronological changes in -aquatic habitats. Of course, modifying factors such as differences -between populations of turtles in rates of evolutionary change, degrees -of vagility, rates of dispersal, and overland migrations need to be -taken into account. - -My accumulation of data on soft-shelled turtles was begun in the early -nineteen-fifties. Although American softshells have been discussed in a -revisionary manner by Agassiz (1857), Siebenrock (1924), Stejneger -(1944) and Neill (1951), the relationships of all the component -populations have not hitherto been appreciated. The present account -attempts to combine in one publication what is known concerning the -taxonomy, geographic distribution, life history, and relationships of -the Recent American species and subspecies of the genus _Trionyx_. - - -Collecting Methods - -Nocturnal collecting, by hand, from a boat that was nosed among brush -piles along the shore line of rivers (Chaney and Smith, 1950:323) in the -early 1950's on rivers of the Gulf Coast drainage east of Texas yielded -many turtles of the genus _Graptemys_ but few softshells. Chaney and -Smith (_loc. cit._) reported only one softshell among 336 turtles taken -in 21 collecting hours on July 5, 6 and 7 on the Sabine River; Cagle and -Chaney (1950:385), however, recorded 11.6 per cent softshells of 208 -turtles (collecting time not stated) taken on the Caddo Lake Spillway in -Louisiana. Using hoop-nets is probably the most efficient method for -collecting softshells considering the time and effort involved, and is -the chief method I have used. Lagler (1943a:24) mentioned the use of -watermelon rind as an effective bait. Kenneth Shain (field notes) -trapped _T. spinifer emoryi_ in hoop-nets baited with bread. I have used -chopped fresh fish with most success; canned sardines have also been -satisfactory. These baits seem to be more successful for trapping -_spinifer_ than they are for _muticus_. Hoop-nets were used to trap -turtles in Lake Texoma, Oklahoma, from June 14 to July 2, 1954. The -number of traps (usually four, rarely five) and trapping success varied -with location. Of 156 turtles, 19 (12%) were _T. spinifer_ and one was -_T. muticus_. - -Trotlines and set lines frequently catch softshells; sport fishermen -often complain of catching these turtles on hook and line. Live worms, -soft-bodied insects, small crawfish, minnows, small pieces of fish and -other kinds of meat are adequate bait. Capture depends on the skill of -attachment of the bait and the size of hook used. In my experience, -softshells (mostly _spinifer_) were taken on trotlines that were set in -lakes or the slower-moving parts of rivers a few inches below the -surface. I have records of only two _muticus_ taken on trotlines. -Goin (1948:304) stated that commercial fishermen catch softshells on -trotlines set for catfish on the bottom of river beds. Evermann and -Clark (1920:595) found softshells to be caught more often than any -other kind of turtle in traps, on set lines, and by anglers in Lake -Maxinkuckee, Indiana. Some residents of the South tell of so placing -baits that turtles are lured to tread water against an object set with -recurved hooks upon which the webbing of the forelimbs are impaled. - -Individuals of _muticus_ and _spinifer_ frequently bury themselves in -sand in shallow water and can be collected by hand by noting swirls or -disturbances on the bottom caused by a turtle withdrawing its head -(Conant, 1951:156, 159). Professional turtle collectors take them by -"noodeling" (Conant, _op. cit._:160); Lagler (1943a:22) elaborated on -the method of "noodling." P. W. Smith (1947:39) remarked that 20 or more -softshells were taken "within a few hours by probing sand bars at the -water edge" near Charleston, Illinois. From a distance I observed an -individual of _T. s. asper_ bury itself in shallow water on the Escambia -River, Florida. Small individuals of _muticus_ have been taken by hand -along the shore of Lake Texoma. Along the Flint River near Bainbridge, -Georgia, two hatchlings that were buried in sand in shallow water -emerged at my approach and scurried a few inches, then buried themselves -again. Larger turtles seem to be more wary. One that was disturbed, -emerged from the sand and swam toward deep water. - -In clear water, water-goggling may be effective in securing softshells. -Marchand (_in_ Carr, 1952:417-18) mentioned that softshells (_ferox_) -can be found buried in deep water with only the heads visible; the -turtles are not easily frightened under water and may be captured by -grasping their necks. A similar technique described by Allen and Neill -(1950:3) resulted in the capture of trionychid turtles. In clear water -of the White River, Arkansas, I collected a few softshells by hand as -they lay on the bottom. - -In shallow-water areas of large rivers, lakes and tributaries, seining -often procures softshells. Methods used in fisheries investigations such -as the application of rotenone and electric shockers, and even -dynamiting, sometimes yield soft-shelled turtles. Carr (1952:419) wrote -that numbers of _ferox_ were incapacitated by rotenone in Florida lakes, -although no other species of turtle was affected. I captured a snapping -turtle (_Chelydra serpentina_) that was immobilized by the current from -an electric shocker in a small, alga-choked tributary of Cache Creek, -Comanche County, Oklahoma; presumably turtles must come in close contact -with the electrodes to be affected (see discussion by Gunning and Lewis, -1957:52). - -The effectiveness of gill nets in trapping turtles is indicated by -information kindly supplied by Mr. Alfred Houser on gill-net operations -from July through December, 1952, under the direction of Mr. "Bud" -Oldham, a commercial fisherman. The 4-inch mesh nets were in Lake Texoma -at the mouth of Briar Creek, two miles south of Powell, Marshall County, -Oklahoma, in 25 to 30 feet of water. Eighty to 90 per cent of the -turtles secured were softshells; more were taken near shoreline than -away from shore even though the depth was about the same. An average of -only one turtle every four days was taken in July and August when the -turtles presumably are most active (Table 1). One gill-net day is -equivalent to one gill net, 200 yards long, operated for 24 hours. - - TABLE 1. The Abundance of Turtles as Revealed by Gill-net - Operations in Lake Texoma, 1952. - - ===========+==========+===========+=============== - | Gill-net | Number of | Gill-net days - MONTH | days | turtles | per turtle - -----------+----------+-----------+--------------- - July | 835 | 213 | 3.9 - August | 816 | 199 | 4.6 - September | 743 | 42 | 17.7 - October | 1661 | 82 | 20.3 - November | 1322 | 48 | 27.5 - December | 864 | 5 | 172.8 - -----------+----------+-----------+--------------- - -Dr. Virgil Dowell, while making fishery studies two miles east of -Willis, Marshall County, Oklahoma, caught, on the average, 1.5 turtles -per day. Of 75 turtles collected from July 1 through October 18, 1953, -66 were _Trionyx_ (_spinifer_ and _muticus_), five were _Graptemys_ and -four were _Pseudemys scripta_. No more than two gill nets were used -simultaneously. The nets were moved from time to time and varied in -dimensions, but those used most of the time were 200 feet long and eight -feet deep with a 3-inch mesh. - -The few captures by Houser probably resulted from long-continued -trapping in one place; the gill nets were not moved in the entire -six-month period or for some time previously. Breckenridge (1955:6) -commented on the sedentary nature of _spinifer_ (in Minnesota) and -quoted a professional turtle trapper as stating that "after a section of -a river has been trapped heavily for softshells, little success can be -expected in that area for as much as three or four years thereafter." -Both Houser's and Dowell's data indicate a higher percentage of -soft-shelled turtles collected than any other species. The number -caught probably depends, at least partly, on the food habits of the -species and is influenced by the enmeshed fish, which, serving as a food -source, attract the turtles. - - -Materials and Procedures - -In the course of this study I examined 1849 soft-shelled turtles, -including some incomplete alcoholic or dried specimens, such as those -represented only by skulls or by other osteological material. Material -was examined from each of the collections named below (except KKA), and -these are mentioned in the text by the following abbreviations: - - AMNH American Museum of Natural History - ANSP Academy of Natural Sciences, Philadelphia - BCB Bryce C. Brown, private collection, Baylor University - CM Carnegie Museum - CNHM Chicago Natural History Museum - INHS Illinois Natural History Survey, University of Illinois - KKA Kraig K. Adler, private collection, data in letter dated January 8, 1960 - KU Museum of Natural History, The University of Kansas - LSU Louisiana State University - MCZ Museum of Comparative Zoology, Harvard College - MSU The Museum, Michigan State University - NHB Naturhistorisches Museum Basel, Switzerland - OU University of Oklahoma Museum, Division of Zoology - SM Strecker Museum, Baylor University - TCWC Texas Cooperative Wildlife Collection, Texas Agricultural and Mechanical College - TNHC Texas Natural History Collection, The University of Texas - TTC Texas Technological College - TU Tulane University - UA University of Alabama - UI Museum of Natural History, The University of Illinois - UMMZ Museum of Zoology, The University of Michigan - USNM United States National Museum - WEB William E. Brode, private collection, Mississippi Southern College - WTN Wilfred T. Neill, private collection - -External measurements (listed under the section, "Variation") were -taken by the writer by means of a Vernier caliper or a steel tape. -Measurements of the skulls are in millimeters and tenths as taken by -the writer with dial calipers. Partial wrinkling of the carapace at -the edges of some specimens causes some error in measurements; -consequently, length of plastron is used as the measurement of -reference. - -Scattergrams based on external measurements were constructed. Some -demonstrate considerable ontogenetic variation. An inspection of the -scattergrams indicated regressions essentially linear in nature, but -sometimes occasioned an arbitrary separation of samples into size -groups to show ontogenetic variation; no secondary sexual differences -could be discerned. Several ratios were developed from the -measurements. The data correspond to the regression model 1A in -"Statistical Methods" (Snedecor, 1956, sec. 6.13); consequently, the -sample ratios indicate the slope of regression and are useful in -comparisons. Sample-means and their estimated standard errors are -compared graphically to show general trends in proportional -characters. Comparisons of means and standard errors indicate -statistical significance between populations if the sample-means plus -or minus twice their standard errors do not overlap, but this method -of comparison is valid only when comparing two samples (Pimentel, -1959:100). - -In the section on "Variation," general features applicable to all -kinds of soft-shelled turtles are discussed under the following -headings: secondary sexual, ontogenetic, and geographic; individual -variation is mentioned in accounts of species and subspecies. In the -section "Character Analysis" external and osteological characters -having taxonomic significance are discussed. - -Vernacular names follow, as closely as possible, those recommended by -the Committee on Herpetological Common Names (1956). The synonymy of -each monotypic species or subspecies begins with the name as given in -the original description. The second entry is the name-combination -herein applied to the taxon. Other entries are first usages, in -chronological order, of other names (synonyms) that have been applied -to the taxon in question. Next, the type is briefly discussed followed -by the "Range" defined in general geographic terms, and, when -appropriate, in terms of river drainage systems. "Diagnosis" includes -a combination of characters that facilitates quick identification. In -polytypic species, the diagnosis of a subspecies is designed only to -distinguish it from other subspecies of that species. The comments -included under the subsection entitled "Description" pertain to -individuals from an area where the taxon is most clearly -differentiated. Because osteological characters are significant only -at the specific level, they appear under the accounts of each species -(excluding _ater_). Proportional characters as given in the -"Diagnosis" are only in general terms; more specific data are set -forth in the subsection, "Description" or in the various text figures, -mostly in the section on "Variation," page 445. Proportions pertaining -to the species _muticus_ were derived only from the nominal -subspecies, and appear under the account of the species. A subsection -"Variation" under the accounts of some subspecies includes information -concerning principally individual variation and coloration; because -color is not considered to be of major taxonomic importance, color -terms are used without reference to any standard color guide. The -subsection "Remarks" follows the section on "Comparisons," and may -include comments on nomenclature, intergradation and other information -related to the distribution or taxonomy of the subspecies. - -The probable geographic range of each species and subspecies is shown -on one of the maps. Locality records of specimens that I have examined -are shown by solid circles. Additional records of occurrence -(published records or specimens otherwise not seen) are shown by -hollow circles. Localities only a short distance apart share the same -circle. - -Under the subsection "Specimens examined," a number in parentheses -following a museum number indicates the number of specimens referable -to that museum number. All localities of specimens examined are -indicated on one of the maps. The list of specimens is arranged -alphabetically by states (Canadian provinces precede states of the -United States under the account of _T. spinifer spinifer_, and Mexican -states follow those of the United States under _T. s. emoryi_), -alphabetically by counties, and within a county alphabetically by -abbreviations of museums; then, museum catalogue numbers are arranged -consecutively. Records in the literature are not included if they -refer to the same locality from which at least one specimen has been -examined, or refer to a less restricted locality that includes the -area from which at least one specimen has been examined. Localities -within a county are arranged alphabetically by author; the appropriate -reference may follow several localities. - -All generic, specific and subspecific names (but not all the different -kinds of name-combinations) that have been applied to American -soft-shelled turtles are listed in a subsection entitled "Synonymy" -under the heading "Genus Trionyx Geoffroy, 1809." - - -Acknowledgments - -Completion of this study has been made possible only by the -co-operation of those persons in charge of the collections listed -above and I am grateful to them for the privilege of examining -specimens. Also I wish to thank Dr. E. Raymond Hall for the facilities -afforded by the Museum of Natural History at the University of Kansas, -as well as for editorial assistance in the preparation of the -manuscript, and especially Dr. Henry S. Fitch under whose guidance -this research was carried out. - -In addition to various staff members, graduate students, and -individuals whose help is acknowledged at appropriate places in the -text, Dr. Rollin H. Baker, Dr. Fred R. Cagle, Mr. J. Keever Greer, Dr. -A. Byron Leonard, Dr. Carl D. Riggs, and Dr. Edward H. Taylor deserve -especial mention for aid extended in the course of this study. I am -indebted to Mr. J. C. Battersby, British Museum (Natural History), -London, for information concerning the type of _Trionyx ferox_, to Dr. -Jean Guibé, Museum d'Histoire Naturelle, Paris, for information -concerning the types of _Trionyx muticus_, _T. spinifer_ and _T. -carinatus_, and photographs of the types of _T. muticus_, _T. -spinifer_ and _T. ocellatus_, and to Dr. Lothar Forcart of the -Naturhistorisches Museum, Basel, Switzerland, for information -pertaining to a published record of _T. muticus_. - -The maps and figures are the work of Miss Lucy Jean Remple and Mrs. -Lorna Cordonnier, University of Kansas. Dr. John M. Legler, University -of Utah, prepared most of the photographs on plates 1-20; photographs -as mentioned in the preceding paragraph were received from Dr. Guibé, -one was provided through the co-operation of Roger Conant and Isabelle -Hunt Conant, another was furnished by Mr. J. Keever Greer, and the -others were taken by me. Field work was financed in part by funds -provided by the Sigma Xi-RESA Research Fund. - - - - -TAXONOMY - - -Family Trionychidae Bell, 1828 - -Recent soft-shelled turtles comprise a well-defined assemblage of the -family Trionychidae. Although the scope of this study does not involve -an assay of the relationships of the soft-shelled turtles of the Old -World, a brief résumé that includes some of the salient characteristics -of the family is included. - -_Diagnosis._--Articulation between last cervical and first dorsal -vertebrae by zygopophyses only; preplastra separated from hyoplastra -by /\-shaped epiplastron, entoplastron absent (Williams and McDowell, -1952:263-75); marginal bones absent or forming an incomplete series, -not connected with ribs that extend beyond pleural plates; claws on -only three inner digits; fourth digit having four or more phalanges; -plastron united to carapace by ligamentous tissue (Smith, 1931:147). - -_General characters._--Size large, "... some attaining probably 5 feet -in length of carapace" (Boulenger, 1890:10); body depressed; carapace -and plastron lacking horny epidermal shields, covered instead with -soft skin; snout ending in fleshy, tubate proboscis; jaws concealed by -fleshy lips; tail short; digits well-webbed; cervical vertebrae -opisthocoelous (eighth having double articulation in front); neck -elongate, cervical region equaling or exceeding length of dorsal -vertebral column; head and neck completely retractile, bending by -means of sigmoid curve in vertical plane; ear hidden; skull elongate, -having three posterior projections (median one produced by -supraoccipital and two lateral projections formed chiefly by -squamosals); temporal region emarginate posteriorly, forming wide -shallow fossa; premaxillae fused; an intermaxillary foramen; -pterygoids separated by basisphenoid that contacts palatines; vomer, -if present, not separating palatines; pelvis not fused to carapace and -plastron; plastron reduced, a median vacuity usually present; plastral -bones developing sculpturing with increase in size, forming four to -seven so-called plastral callosities; carapace with or without -prenuchal bone; nuchal overlapping or overlapped by first pleural; -neurals in continuous series or interrupted by pleurals; bony plates -of carapace sculptured; mandible having well-developed coronoid bone; -cutaneous femoral valves that conceal hind limbs present or absent; -two or three pairs of scent glands; cloacal bursae absent (Smith and -James, 1958:89); forelimbs having antebrachial scalation; body of -hyoid apparatus formed of two or three pairs of bones; penis broad, -expanded and pentifid, sulcus spermaticus quadrifid having branches in -each of four lateral projections (Hoffman, 1890:298, pl. 47, fig. 2); -aquatic, principally in fresh water; mainly carnivorous; flesh of many -species eaten. (See Boulenger, 1889:237-41; Loveridge and Williams, -1957:412; Romer, 1956:513; Smith, _op. cit._:147-54). - -_Recent distribution_ (Figure 1).--North America, from extreme -southeastern Canada and eastern United States west to Rocky Mountains -and south to northern México; introduced in southwestern United States -(Conant, 1958:69-73). Africa, from Egypt and Senegal south to Angola -and Zambesi River drainage (Loveridge and Williams, _op. -cit._:412-68); occurrence of _Trionyx triunguis_ in Syria (Boulenger, -_op. cit._:255) and coastal streams of Palestine (Schmidt and Inger, -1957:36) considered accidental by Flower (1933:753-54). Southwestern -Asia (Tigris and Euphrates River drainage) in eastern Turkey, Syria, -Iraq and northeastern Israel (Mertens and Wermuth, 1955:388). -Southeastern Asia, from Pakistan and India (Indus River drainage) and -Manchuria and adjacent Siberia (Amur River drainage) to Ceylon, Japan, -Formosa, Hainan, Luzon, Sumatra, Java, Borneo, Timor and southeastern -New Guinea (De Rooij, 1915:325-32; Okada, 1938:108; Pope, 1935:60-64; -Smith, 1931:158-79; Stejneger, 1907:514-532; Taylor, 1920:141). - -_Trionyx cartilagineus_ is questionably recorded from the Moluccas (De -Rooij, _op. cit._:330). _T. sinensis_ has been introduced on Kauai -Island, Hawaiian Islands (Brock, 1947:142; Oliver and Shaw, 1953:83), -one of the Bonin Islands (Okada, 1930:187-94), and probably Timor (De -Rooij, _op. cit._:331). All insular records east of Borneo and Java -are probably the result of introductions, except perhaps those of -_Pelochelys_ on Luzon and New Guinea (Darlington, 1957:210). - - [Illustration: FIG. 1. Geographic distribution of the family - Trionychidae.] - -_Recent genera._--According to Mertens and Wermuth (1955:387-95), there -are 21 species belonging to six genera as follows: - - _Chitra_ Gray, 1844 (1) - _Cyclanorbis_ Gray, 1854 (2) - _Cycloderma_ Peters, 1854 (2) - _Lissemys_ Smith, 1931 (1) - _Pelochelys_ Gray, 1864 (1) - _Trionyx_ Geoffroy, 1809 (14) - -_Dogania_ is considered a synonym of _Trionyx_ (Loveridge and Williams, -_op. cit._:422). - -_Geologic range._--Lower Cretaceous (possibly Upper Jurassic) to Recent -of Asia; Upper Cretaceous to Recent of North America; Paleocene (Upper -Jurassic, assuming _Trionyx primoevus_ is a trionychid) to Pleistocene -of Europe; Lower Miocene to Recent of Africa; Pleistocene to Recent in -East Indies (Loveridge and Williams, _op. cit._:412; Romer, 1945:594); -questionable trionychid fragments from Pleistocene of Australia -(Darlington, _loc. cit._). $/ - -_Remarks._--The genera _Lissemys_, _Cyclanorbis_ and _Cycloderma_ are -distinguished from _Pelochelys_, _Chitra_ and _Trionyx_ by several -characters (Loveridge and Williams, _op. cit._:414). The recognition of -two groups of genera caused Deraniyagala (1939:290) to erect two -families, Cyclanorbidae and Trionychidae. An appraisal of fossils -prompted Hummel (1929:768) to propose two corresponding subfamilies, -Cyclanorbinae and Trionychinae. Williams (1950:554) considered the two -groups as subfamilies (Lissemydinae and Trionychinae). - -Baur (1887:97) regarded the Trionychidae as constituting a separate -suborder distinct from the rest of the living turtles. Later (1891), -however, he pointed out the resemblances of the Trionychidae and -Carettochelyidae (having one living genus in New Guinea), and the -cryptodiran affinities of _Carettochelys_. Bergounioux (1932:1408) -mentioned the close resemblance of the Carettochelyidae to _Trionyx_ but -considered the former as having pleurodiran affinities, a view adopted -by Deraniyagala (_loc. cit._). Most students now consider the two -families to be closely related, and conceive of both as members of the -suborder Cryptodira (Hummel, 1929:768; Williams, _loc. cit._; Mertens -and Wermuth, 1955). - -The oldest trionychid fossil, _Trionyx primoevus_, is from marine -deposits of the Upper Jurassic (Kiméridgien) from "Cap de la Hève," and -its characters do not indicate the kind of cryptodiran ancestor from -which the family arose (Bergounioux, _op. cit._:1409; 1937:188). Lane -(1910:350) found that the entoplastron (= epiplastron) was paired in -embryos of _Trionyx_ and regarded that genus as the most primitive of -the order; he also mentioned Wiedersheim's report of rudiments of teeth -in embryos of _Trionyx_. Baur (1891:637-38) thought that the family -arose directly from the Amphichelydia, that the ancestors of the -Trionychidae closely resembled _Carettochelys_ in the structure of the -carapace and plastron, and that a progressive reduction in ossification -of those structures occurred. Nopcsa (1926:654) also wrote that the -family originated from ancestors having a well-developed plastron; he -maintained that the progressive reduction in ossification of the -plastron was a specialization for aquatic life, and that the more -primitive trionychids had the best developed bones and callosities. -Hummel (1929:772) also thought that there had been a progressive -reduction in ossification. Bergounioux (1932:1408; 1936:1088, -1952:2304), on the contrary, thought that there had been a progressive -increase in ossification of the marginal bones in both families as well -as of the plastron (1936:1088; 1937:190). Zangerl's study of the shell -elements of turtles (1939:393) indicated that _Trionyx_ was highly -specialized in having a well-developed epithecal armor (sculptured -callosities, neurals and costals), and that it occurred in most aquatic -turtles; the development in soft-shells suggested that members of the -family had maintained an aquatic mode of life over a long period of -geologic time, a view supported by Deraniyagala (1930:1066). Of interest -are Stunkard's remarks (1930:214-18) concerning several _Trionyx -spinifer_ that were obtained from a commercial supply house and found to -be infested with pronocephalid trematodes (_Opisthoporus_ [= -_Teloporia_] _aspidonectes_). The closest relatives of that trematode -(also recorded from _T. ferox_) live in marine turtles. Possibly, a -Mesozoic ancestor of marine and essentially fresh-water soft-shelled -turtles harboured ancestors of these trematodes, but possibly the -parasites may have transferred relatively recently to their present -hosts. Bergounioux (1937:190) judged the Trionychidae to be an ancient -group of marine origin. Hummel (1929:770) wrote that the Trionychidae -originated in east Asia (the region of most differentiation) in humid -climates. - -Baur (1891:634, 637) pointed out that the dorsal aspect of the skull of -the closely related _Carettochelys_ resembles the skull of the -Dermatemydidae, Staurotypidae and Kinosternidae; the close relationship -of _Carettochelys_ and the Dermatemydidae is also mentioned by -Bergounioux (1952:2304) and Hummel (1929:769). Hummel (_op. cit._:771) -thought that the Carettochelyidae and "die Chelydroiden" had a common -ancestor, and that (_op. cit._:772) the origin of the Trionychidae was -older than those two groups. Dunn (1931:109) wrote that the -Kinosternidae, Carettochelyidae and Dermatemydidae represented the same -general ancestry. Williams (1950:552) has shown the resemblance of the -cervical articulations in members of the Chelydridae (including -Staurotypinae and Kinosterninae) and the Central American family -Dermatemydidae. The consensus of opinion, then, is that the families -Trionychidae, Carettochelyidae, Chelydridae and Dermatemydidae are -relatively closely related. - - -Genus =Trionyx= Geoffroy, 1809 - - _Testudo_ Linnaeus (in part), Syst. Nat., Ed. 10, 1:197, 1758; type, - _Testudo graeca_ Linnaeus by subsequent designation (Fitzinger, - 1843:29). - - _Trionyx_ Geoffroy, Ann. Mus. Hist. Nat. Paris, 14:1, August, 1809; - type, _Trionyx aegyptiacus_ (= _Testudo triunguis_ Forskål) by - original designation. - - _Apalone_ Rafinesque, Atlan. Jour., Friend of Knowledge, - Philadelphia, 1 (No. 2, Art. 12):64, Summer, 1832; type, _Apalone - hudsonica_ (= _Trionyx spiniferus_ Lesueur) by monotypy. - - _Mesodeca_ Rafinesque, Atlan. Jour., Friend of Knowledge, - Philadelphia, 1 (No. 2, Art. 12):64, Summer, 1832; type _Mesodeca - bartrami_ (= _Testudo ferox_ Schneider) by monotypy. - - _Aspidonectes_ Wagler, Naturl. Syst. Amphib., p. 134, 1830; type, - _Aspidonectes aegyptiacus_ Wagler (= _Testudo triunguis_ Forskål) - by subsequent designation (Fitzinger, 1843:30). - - _Amyda_ Fitzinger, Ann. Wiener Mus. Naturg., 1:110, 120, 127, 1835; - type, _Amyda subplana_ Fitzinger by subsequent designation - (Fitzinger 1843:30). - - _Gymnopus_ Duméril and Bibron, Erpét. Gén., 2:472, 1835; new - (substitute) name for _Aspidonectes_ Wagler. - - _Pelodiscus_ Fitzinger, Ann. Wiener Mus. Naturg., 1:110, 120, 127, - 1835; type, _Pelodiscus sinensis_ Fitzinger by subsequent - designation (Fitzinger, 1843:30). - - _Platypeltis_ Fitzinger, Ann. Wiener Mus. Naturg., 1:109, 120, 127, - 1835; type, _Platypeltis ferox_ by subsequent designation - (Fitzinger, 1843:30). - - _Potamochelys_ Fitzinger, Syst. Rept., p. 30, 1843; type, - _Aspidonectes javanicus_ Wagler (= _Testudo cartilaginea_ - Boddaert) by original designation. - - _Tyrse_ Gray, Cat. Tort. Croc. Amphis. Brit. Mus., p. 48, 1844; - type, _Tyrse nilotica_ Gray (= _Testudo triunguis_ Forskål) by - tautonomy (_Tyrse_, a name for the Nile River). - - _Callinia_ Gray, Proc. Zool. Soc. London, p. 222, 1869; new - (substitute) name for _Aspidonectes_ of Agassiz (1857:403); type, - _Callinia spicifera_ (mispelling for _spinifera_) Gray by - subsequent designation (Stejneger, 1907:514). - - _Euamyda_ Stejneger, Bull. Mus. Comp. Zool., 94:7, 9, 12, 1944; new - (substitute) name for _Amyda mutica_ of Agassiz (1857:399); type, - _Amyda mutica_ Agassiz by monotypy. - -_Type Species._--_Trionyx aegyptiacus_ (= _Testudo triunguis_ -Forskål). - -_Diagnosis._--Cutaneous femoral valves absent; width of postorbital -arch of skull less than diameter of orbit; pterygoids usually not -contacting opisthotics; carapace lacking prenuchal bone and marginal -ossifications; nuchal bone lacking conspicuous ventral ridges; -posterior margin of nuchal overlying first pair of pleurals; lateral -parts of nuchal bone overlying second pair of ribs; neurals seven or -eight, rarely six or nine; pleurals seven or eight pairs, posterior -one or two pairs sometimes in contact medially; distinct suture -usually present between hyoplastra and hypoplastra; most laterad prong -of posteromedial process of hypoplastra inserted between bifid -anterolateral process of xiphiplastra. - -_Synonomy._--Geoffroy published a synopsis of the species he -recognized (1809) prior to his formal description of the genus -_Trionyx_ (1809a). Schweigger, nevertheless, probably was the first -person to recognize the soft-shelled turtles as a distinct group, and -he proposed for it the name _Amyda_ in an unpublished manuscript that -he sent to Geoffroy. The latter author (1809a:15) relegated the name -_Amyda_ to the synonomy of _Trionyx javanicus_ by means of the -following entry: "_Amyda javanica._ Schweigger, dans un manuscript -communique a l'Institut." Stejneger (1944:7) maintained that this -publication of Schweigger's monotypic generic name clearly established -its availability for the species congeneric with _Amyda javanica_ (= -_Testudo cartilaginea_ Boddaert, 1770). Loveridge and Williams -(1957:422) contend that this mere mention of the name _Amyda_ neither -constitutes the proposal of a new name nor validates it, and that the -first valid usage of the name _Amyda_ is that of Fitzinger (1835:120), -who later (1843:30) designated the type species as _Amyda subplana_. -The name _Amyda_ cannot date from _Oken_ (1816:348) as Volume 3 -[Zoologie] of his Lehrbuch der Naturgeschichte published in 1815-1816 -has been placed on the Official Index of Rejected and Invalid Works in -Zoological Nomenclature with the Title No. 33; see Opinion 417 -(Hemming, 1956). - -There has been considerable debate as to whether Geoffroy did or did -not designate a type species of the genus _Trionyx_ (1809a). Although -not specifically designated as the type species, _Trionyx aegyptiacus_ -(= _Testudo triunguis_ Forskål) is considered by Smith (1930:2), -Schmidt (1953:108, footnote), and Loveridge and Williams (1957:422) to -have been sufficiently indicated by Geoffroy as the type species. But -Stejneger (1944:6), H. M. Smith (1947:122), Conant and Goin -(1948:11), and Mertens and Wermuth (1955) maintained that Geoffroy did -not adequately designate a type species, and that Fitzinger (1843:30) -designated the type species as _Trionyx granosus_ (= _Lissemys -punctata_), a synonym of Geoffroy's species, _coromandelicus_. - -If Fitzinger's designation of a type species is accepted, the name -_Trionyx_ is applicable to the forms herein referred to _Lissemys_, -and _Amyda_ to the American forms. If Geoffroy's designation is -accepted, the American forms are referable to _Trionyx_, and _Amyda_ -is a synonym. - -The preceding includes only those generic names (listed in -chronological order) that have been applied to Recent American -soft-shelled turtles. Generic synonyms of the genus _Trionyx_ -applicable to Old World species are listed by Stejneger (1907:514), -Smith (1931:165), and Loveridge and Williams (1957:420-21). - -_Trionyx_ is the most widespread genus of the family; most of the -species occur in southeastern Asia. All North American soft-shelled -turtles belong to this genus. - -For quick reference, all the specific and subspecific names proposed -for soft-shelled turtles in North America are listed below in -alphabetical order (left hand column) with their nomenclatural status -as recognized in this paper. The synonyms are listed in the account of -the appropriate species or subspecies, and are discussed under the -subsection entitled "Remarks." - - _agassizi_ _Trionyx spinifer asper_ - _annulifer_ _Trionyx spinifer spinifer_ - _argus_ _Trionyx spinifer spinifer_ - _asper_ _Trionyx spinifer asper_ - _ater_ _Trionyx ater_ - _bartrami_ _Trionyx ferox_ - _emoryi_ _Trionyx spinifer emoryi_ - _calvatus_ _Trionyx muticus calvatus_ - _ferox_ _Trionyx ferox_ - _georgianus_ _Trionyx ferox_ - _georgicus_ _Trionyx ferox_ - _harlani_ _Trionyx ferox_ - _hartwegi_ _Trionyx spinifer hartwegi_ - _hudsonica_ _Trionyx spinifer spinifer_ - _mollis_ _Trionyx ferox_ - _microcephalus_ _Trionyx muticus muticus_ - _muticus_ _Trionyx muticus muticus_ - _nuchalis_ _Trionyx spinifer spinifer_ - _ocellatus_ _Trionyx spinifer spinifer_ - _olivaceus_ _Trionyx spinifer spinifer_ - _spiniferus_ _Trionyx spinifer spinifer_ - - -Variation - -Aside from qualitative variations and comparisons of patterns of -pigmentation the following external measurements (to the nearest -millimeter) were used. - -_Length of plastron_: Maximal straight-line measurement -(midventrally), from the anteriormost region of the ventral surface to -the posterior end of the plastron; this measurement includes an -anterior cartilaginous part. - -_Length of carapace_: Maximal, straight-line measurement -(middorsally), from the nuchal region to the posteriormost region of -the free edge of the carapace. - -_Width of carapace_: Maximal, straight-line measurement between the -lateral margins of the carapace. - -_Plane of greatest width of carapace_: Maximal, straight-line -measurement from the posteriormost region of the free edge of the -carapace to a point on the middorsal line at the level or plane of the -greatest width of the carapace; this measurement and the last two, of -course, include the fringing cartilaginous parts of the dorsal bony -carapace. - -_Width of head_: Maximal measurement between the lateral margins of -the head. - -_Length of snout_: Measurement from tip of snout to interorbital -region of least breadth. - -_Diameter of ocellus_: Maximal outside diameter of largest (not -conspicuously ovoid or oblong) ocellus on carapace. - -The following ratios were developed from the measurements. Reference -to these ratios will be made by the abbreviations within the -parentheses: length of carapace/length of plastron (CL/PL); length of -carapace/width of carapace (CL/CW); length of carapace/plane of width -of carapace (CL/PCW); length of plastron/width of head (PL/HW); width -of head/length of snout (HW/SL); diameter of ocellus/length of -plastron (OD/PL). - - -Secondary Sexual Variation - - -_Size_ - -In many species of turtles, females are larger than males; the -difference in size between the sexes is probably most pronounced in -aquatic emydids. The ten largest individuals of each sex were selected -to indicate the relative difference in size between the sexes of the -three American species of _Trionyx_ (excluding _ater_, Table 2). -Female soft-shelled turtles attain a larger size than males. _T. -ferox_ is the largest species; _muticus_ is the smallest. The -approximate maximal size of each sex and the difference in size -between the sexes are more correctly expressed for _spinifer_ and -_muticus_ than for _ferox_, because fewer specimens of _ferox_ were -examined; presumably the approximate maximal size of males and females -of _ferox_ is larger than is indicated in Table 2. - - TABLE 2. Secondary Sexual Difference in Maximal Size of North - American Species of the Genus Trionyx (excluding ater) Based - on the Ten Largest Specimens of Each Sex of Each Species. - The Extremes Precede the Mean (in parentheses). - - =============+============================ - SPECIES | Plastral length (cm.) - -------------+---------+------------------ - _ferox_ | males | 17.0-26.0 (20.0) - | females | 23.3-34.0 (27.9) - | | - _spinifer_ | males | 13.8-16.0 (14.4) - | females | 26.0-31.0 (28.0) - | | - _muticus_ | males | 11.8-14.0 (12.3) - | females | 17.7-21.5 (18.9) - -------------+---------+------------------ - - -_Pattern_ - -Secondary sexual differences in pattern are probably more pronounced -in soft-shelled turtles than in other species of turtles, except -perhaps for the well-known melanism and concomitant obliteration of -pattern acquired by some adult males of the _scripta_ section of the -genus _Pseudemys_. - -The difference in pattern between the sexes of American species varies -with size of the individual and with the species and subspecies. The -juvenal pattern of some individuals of _T. spinifer asper_ differs -according to sex. In the other species and subspecies, there are no -secondary sexual differences in the juvenal pattern. That pattern in -females of all species and subspecies is partly or entirely obscured -by a mottled and blotched pattern as growth proceeds. This mottled and -blotched pattern is present on females not yet sexually mature, and is -of contrasting lichenlike figures, and in other individuals is less -contrasting and a more uniform coloration. The largest males of _T. -spinifer_ retain a conspicuous juvenal pattern; in those of _muticus_ -the pattern may be well-defined or partly modified and obscured, -whereas in large males of _ferox_ the juvenal pattern is ill-defined -or absent. No male normally acquires a contrasting mottled and -blotched pattern on the carapace. The pattern on the carapace of many -large individuals of _ferox_ is not distinctive as to sex. - -On the dorsal surface of the soft parts of the body there is a -contrasting pattern in adult males and hatchlings of some forms, but -in most large females the pattern is usually reduced to a near-uniform -coloration; the pattern on adult males of _ferox_ and _muticus_ is not -contrasting and resembles that on large females. - - -_Coloration_ - -Because most specimens examined were preserved, the detection of -secondary sexual differences in coloration was difficult. There is one -difference in coloration between the sexes in the subspecies _T. s. -emoryi_. Males from the Río Grande drainage, at least those from the -Big Bend region of Texas, and southwestward in the Río Conchos into -Chihuahua, México, are bright orange on the side of head (postlabial -and postocular pale areas); an orange tinge also occurs in pale -stripes on the snout, and pale orange blotches sometimes occur on the -dorsal surfaces of limbs, especially the hind limbs. The coloration of -these areas on females is pale yellow, lacking orange. - - -_Tuberculation_ - -In all subspecies of _spinifer_ the carapace of adult males is -"sandpapery" owing to abundant, small, spiny tubercles distributed -over its surface; all females lack spiny tubercles on the surface of -the carapace. - - -_Length of Tail_ - -Elongation of the preanal region of the tail resulting in the -extension of the cloacal opening beyond the posterior edge of the -carapace occurs in males of several kinds of turtles, including -_Trionyx_, at least in those from Louisiana, Texas, and Lake Texoma, -Oklahoma (Webb, 1956:121). Probably this elongation is characteristic -of males of all American softshells. Some females of _spinifer_ and -_muticus_ that exceed the maximum size attained by males have the tip -of the tail and cloacal opening extending a short distance beyond the -posterior edge of the carapace. Some large females of _ferox_ have -more elongate tails than those of _spinifer_ and _muticus_. - - -_Width of Alveolar Surfaces of Jaws_ - -Stejneger (1944:34-36, pl. 6) commented on a series of large skulls of -_ferox_ mostly from Kissimmee, Florida, some of which had -conspicuously expanded alveolar surfaces. He suggested that the -condition was confined to large males. A scattergram (Fig. 2) based on -measurements obtained from 45 skulls of _ferox_ shows widened alveolar -surfaces of the upper jaws on some of the larger skulls. Because the -maximal size of adult males is unknown and the difference in size -between the sexes of _ferox_ is slight, such large skulls might -represent either sex. The sex had been recorded for only three of the -45 skulls; none of the three exceeded 82 millimeters in basicranial -length or had widened alveolar surfaces. Some of the larger skulls of -approximately the same size differ markedly in width of the alveolar -surfaces; this difference suggests that both sexes are included and -that the sexes may be of approximately the same maximal size. On the -other hand, the variation observed in skulls is possibly confined to -one sex. To judge from what is known of the maximal sizes of the sexes -of _spinifer_ and _muticus_ (see Table 2), skulls of _ferox_ of more -than 85 millimeters in basicranial length probably are of females. The -largest alcoholic male (dissected) of _ferox_ that I examined had a -width of head of approximately 46.5 millimeters; that measurement -corresponds to a basicranial length of 70 to 75 millimeters. The -specimen of which measurements are depicted by the uppermost symbol in -the scattergram (represented by KU 16528) was recorded as a female. -Large females of _T. s. asper_ from rivers emptying into the Atlantic -Ocean have broadened alveolar surfaces. - - [Illustration: FIG. 2. Basicranial length and greatest width of - alveolar surface of upper jaw on 45 skulls of _T. ferox_. Some - skulls (sex unknown) in which the basicranial length exceeds - 85 mm. develop widened alveolar surfaces of the jaws.] - -_Length of Claw_ - -Secondary sexual differences in length of claw on the forelimb are -pronounced in some kinds of turtles. Cahn (1937:178) stated that the -female of _Trionyx muticus_ usually has long claws on the hind feet, -while the male has long claws on the forefeet, but I am unable to -substantiate his statement. Measurements of length of the third claw -on the hind limb taken in 41 males and 45 females of _spinifer_ from -Louisiana showed no secondary sexual difference. - - -Ontogenetic Variation - - -_Pattern_ - -In all species and subspecies the juvenal pattern is replaced in -females as growth proceeds by a mottled and blotched pattern that is -contrasting or of nearly uniform coloration. The blotched pattern (of -lichenlike figures) is evident on the carapaces of most females that -have plastra so long as 8.0 centimeters. The contrasting juvenal -pattern on the dorsal surfaces of the soft parts of the body is -correspondingly modified in females, but at a size larger than 8.0 -centimeters. Size of ocelli (OD/PL) in _T. s. spinifer_ and _hartwegi_ -seems to vary ontogenetically (see section on Geographic Variation). - -Some hatchlings have blotched patterns (_T. spinifer asper_, TU -16689.2, plastral length, 3.5 cm.); the largest females examined that -did not show any evidence of mottling were two _asper_ having -plastrons 7.6 and 8.0 centimeters in length. Variation in color and -pattern probably is modified greatly by the environment (Heude _in_ -Stejneger, 1907:518, footnote d) and the physiological condition of -the individual. Smith, Nixon and Minton (1949:92) reported that a -female of _T. s. hartwegi_ developed a striking melanistic pattern in -captivity and they concluded that patterns of soft-shelled turtles may -be produced not only by conventional chromatophores, but also by other -depositions, both intra- and extracellular. TU 16170, taken from -brackish water at Delacroix Island, St. Bernard Parish, Louisiana, is -the only adult male I have seen that had a blotched pattern -(orange-brown in life) on the carapace in addition to the juvenal -pattern. One female of _muticus_, KU 48229, having a plastral length -14.5 centimeters, retained a well-defined juvenal pattern, and lacked -a mottled and blotched pattern (see Pl. 46). - - -_Tuberculation_ - -Males of the subspecies of _spinifer_ develop small, sharp tubercles -on the dorsal surface of the carapace when sexually mature. As growth -proceeds, the minute prominences along the anterior edge of the -carapace on hatchlings of both sexes of _spinifer_ change in shape to -conical projections or low, flattened, scarcely-elevated prominences, -depending on the subspecies (Fig. 8). - -Large females of _spinifer_ and _ferox_ acquire enlarged, flattened -knobs in the nuchal region and posteriorly in the center of the -carapace. - - -_Length of Tail_ - -The preanal region of the tail rapidly elongates in males of all -soft-shells when they are sexually mature. - - -_Width of Alveolar Surfaces of Jaws_ - -The alveolar surfaces of the jaws are conspicuously broadened in large -adults of _ferox_, and females of that population of _T. s. asper_ in -the Atlantic Coast drainage. - - -_Ratios_ - -Width of head increases at a rate slightly slower than does the length -of the plastron (PL/HW, Fig. 3). The change in proportions is most -pronounced at a plastral length of 7.5 to 8.0 centimeters. In -general, the head is narrowest in _muticus_ and widest in _ferox_. _T. -s. asper_ and _emoryi_ seemingly have the widest heads among the -subspecies of _spinifer_. Geographically width of head increases from -_spinifer_ and _hartwegi_ through _pallidus_ and _guadalupensis_ to -_emoryi_. _T. ater_ terminates the cline; 12 specimens, ranging in -plastral length from 9.6 to 18.4 centimeters, resemble _ferox_ and -_asper_ in having wide heads (average PL/HW of 4.93). - - [Illustration: FIG. 3. Ratio of length of plastron to width of head - (PL/HW) in some American species and subspecies of the genus - _Trionyx_. The size of each sample is given in parentheses - following an indication of the range (< = less than, > = greater - than) in length of plastron (in cm.) of each sample. The horizontal - line indicates the observed variation; the vertical line, the mean; - the white rectangle, four standard deviations; and the black - rectangle, four standard errors of the mean. There is some - ontogenetic variation in PL/HW. The head is narrowest in _muticus_ - and widest in _ferox_.] - - -The carapace increases in width more slowly than it increases in -length (CL/CW, Fig. 4). The change in proportions is most pronounced -when the carapace is 8.0 to 8.5 centimeters in length. Ontogenetically -_muticus_ varies least and _ferox_ most; large specimens of _ferox_ -have narrower carapaces than _muticus_ of corresponding size. There is -also an indication of a geographical gradient that parallels the cline -mentioned above for PL/HW. There is a gradual decrease in width of -carapace from _pallidus_ through _guadalupensis_ to _emoryi_. Of the -subspecies of _spinifer_, _emoryi_ has the narrowest carapace and -resembles _ferox_. In _T. ater_ this cline is accentuated and -terminates; 12 specimens, ranging in plastral length from 9.6 to 18.4 -centimeters, resemble _ferox_ and _emoryi_ in having narrow carapaces -(average CL/CW of 1.32). - - -_Osteological Characters_ - -Closure of the anterior, paravertebral fontanelles on the bony -carapace, and size and number of plastral callosities are subject to -ontogenetic variation (see sections entitled "Carapace" and -"Plastron"). - - [Illustration: FIG. 4. Ratio of length of carapace to width of - carapace (CL/CW) in some American species and subspecies of the - genus _Trionyx_. Symbols as in Fig. 3. There is some ontogenetic - variation in CL/CW (least in _muticus_). The carapace is - narrowest in _ferox_ and _emoryi_, and widest in _muticus_, - _pallidus_ and _asper_.] - - [Illustration: FIG. 5. Pattern on dorsal surface of snout of some - American species and subspecies of the genus _Trionyx_. Note the - gradual transition in pattern from that of _hartwegi_ (b) and - _asper_ (c) to that of _emoryi_ (h). - - a. _T. ferox_ (UMMZ 102276, × 1/3) - b. _T. spinifer hartwegi_ (KU 46742, × 3/4) - c. _T. spinifer asper_ (KU 50842, × 1) - d. _T. spinifer pallidus_ (KU 2958, × 1/2) - e. _T. spinifer pallidus_ (KU 2934, × 1/2) - f. _T. spinifer pallidus_ (KU 2947, × 1/2) - g. _T. spinifer guadalupensis_ (TU 10165, × 2/3) - h. _T. spinifer emoryi_ (KU 48218, × 2/3) - i. _T. muticus muticus_ (KU 48236, × 2/3) - ] - - -Geographic Variation - -Geographic variation occurs in _Trionyx spinifer_ and _T. muticus_. -The variant populations of _spinifer_ are segregated into six -subspecies, those of _muticus_ into two. In the subspecies of -_spinifer_ there is both group variation and clinal variation. - - -Group Variation - -The six subspecies of _spinifer_ can be separated into two groups on -the basis of the juvenal pattern. One group (subspecies _spinifer_, -_hartwegi_ and _asper_) has a pattern of dark spots or ocelli of -various sizes on the carapace, whereas the other group (subspecies -_pallidus_, _guadalupensis_ and _emoryi_) has a pattern of small white -dots or tubercles on the carapace. The two groups differ also in the -manner in which the mottled and blotched pattern first appears on the -carapace of females. Usually, contrasting lichenlike figures initially -surround the dark spots or ocelli on the carapace in females of the -_spinifer_ group (less evident in _pallidus_), whereas females of the -_emoryi_ group usually lack a contrasting pattern early in ontogeny. -In general, the two groups differ in the degree of pigmentation. The -_spinifer_ group has larger marks and more contrasting patterns on the -head and limbs, and more extensive pigmentation on the ventral surface -than members of the _emoryi_ group. _T. ater_ is more closely related -to those subspecies of the _emoryi_ group but differs in having the -ventral surface heavily speckled with black and an over-all blackish, -dorsal coloration; the underlying pattern of _ater_ resembles that of -_emoryi_. - - -Clinal Variation - -Several characters are arranged in a geographical gradient or cline. -Some characters are relatively uniform and represent a terminus in the -_spinifer_ group. Some characters change gradually and successively -through the subspecies _pallidus_ and _guadalupensis_, and terminate -in _emoryi_ and _T. ater_. Some characters of _ater_, in turn, show -affinity with _T. muticus_ and _T. ferox_. - - -_Pattern on Snout_ - -The pattern (Fig. 5) on the snout usually consists of pale, -dark-bordered stripes that form an acute angle in front of the eyes in -_spinifer_, _hartwegi_ and _asper_, but the corresponding marks form a -dark triangle the base line of which joins the anterior margins of the -orbits in _emoryi_ and usually in _guadalupensis_. In _pallidus_, the -geographic range of which is between _guadalupensis_ and _hartwegi_, -there are different patterns that are in various degrees intermediate -between those described immediately above for _hartwegi_ and -_guadalupensis_. - - -_Pattern on Side of Head_ - -The change in pattern (Fig. 6) and its contrast with the ground color -on the side of the head parallels the sequence of changes in pattern -on the snout. The pattern on the side of head contrasts with the -ground color and consists of dark markings below the eye and on the -neck, an indication of a postlabial stripe, and a pale, dark-bordered -postocular stripe that may be variously interrupted (_spinifer_ and -_hartwegi_; _asper_ usually has uninterrupted postocular and -postlabial stripes that unite on the side of the head). The pattern is -contrasting but variable in _pallidus_. _T. s. emoryi_ and usually -_guadalupensis_ have fewer dark markings, sometimes none, and an -interrupted postocular pale stripe that produces a pale blotch just -behind the eye. - - [Illustration: FIG. 6. Pattern on side of head of some American - species and subspecies of the genus _Trionyx_. Note the gradual - reduction in contrast of pattern and interruption of the postocular - stripe from that of _spinifer_ (b) to that of _emoryi_ (f). - - a. _T. ferox_ (UMMZ 102276, × 1/3) - b. _T. spinifer spinifer_ (UMMZ 54401, × 2/3) - c. _T. spinifer asper_ (KU 50843, × 2/3) - d. _T. spinifer pallidus_ (KU 50830, × 3/4) - e. _T. spinifer guadalupensis_ (SM 659, × 2/3) - f. _T. spinifer emoryi_ (KU 2922, × 3/4) - g. _T. muticus muticus_ (KU 48228, × 2/3) - h. _T. muticus calvatus_ (KU 47117, × 2/3) - ] - - [Illustration: FIG. 7. Pattern on the dorsal surface of the distal - part of the right hind limb of some American species and subspecies - of the genus _Trionyx_. Note the gradual reduction in contrast of - pattern from that of _hartwegi_ (a) to that of _emoryi_ (d). - - a. _T. spinifer hartwegi_ (KU 15932, × 3/4) - b. _T. spinifer pallidus_ (KU 40175, × 2/3) - c. _T. spinifer guadalupensis_ (TU 10165, × 3/4) - d. _T. spinifer emoryi_ (KU 3153, × 5/6) - e. _T. muticus muticus_ (KU 48228, × 3/4) - f. _T. ferox_ (UMMZ 102276, × 1/2) - ] - - [Illustration: FIG. 8. Shape of tubercles on anterior edge of - carapace in some American species and subspecies of the genus - _Trionyx_ (× 1/2). Note the gradual reduction in size of - tubercles from that of _hartwegi_ (b) to that of _muticus_ (h). - - a. _T. ferox_ (UMMZ 90010) - b. _T. spinifer hartwegi_ (KU 3346) - c. _T. spinifer pallidus_ (TU 13213) - d. _T. spinifer guadalupensis_ (TU 10160) - e. _T. spinifer emoryi_ (KU 2906) - f. _T. ater_ (KU 46906) - g. _T. muticus muticus_ (KU 48229) - h. _T. muticus muticus_ (KU 48232) - ] - -_Pattern on Dorsal Surface of Limbs_ - -A corresponding sequence of change occurs in the size of dark markings -on the dorsal surface of the limbs (Fig. 7). The hind limb usually has -larger markings than the forelimb. The change is gradual from larger -and darker markings (contrasting pattern) in _hartwegi_, _spinifer_ -and _asper_ to smaller and paler markings (non-contrasting pattern) in -_emoryi_. - - -_Tuberculation_ - -There is also a cline in tuberculation (Fig. 8) that parallels -geographically the sequence of changes in patterns mentioned -immediately above. The size of the tubercles along the anterior edge -of the carapace changes in both sexes from those that are enlarged and -equilateral or conical in shape in _spinifer_, _hartwegi_, _asper_ and -_pallidus_ to those that are scarcely elevated in _guadalupensis_, -_emoryi_ and _T. ater_. Indeed, in the three kinds mentioned last, the -tubercles are absent in some specimens. There seems to be a -corresponding reduction in the size and number of small, sharp-tipped -tubercles that cover the carapace in adult males; the carapace of _T. -ater_ is mostly smooth and has only a few small, whitish tubercles. - - [Illustration: FIG. 9. Anteroposterior position of plane of - greatest width of carapace (CL/PCW) in some American species - and subspecies of the genus _Trionyx_. Symbols as in Fig. 3. - The greatest width of carapace is midway between anterior and - posterior ends in _ferox_, _spinifer_, _hartwegi_, _asper_ and - _muticus_, and farther posterior in the other subspecies of - _spinifer_.] - - -_Ratios_ - -The clinal tendencies in PL/HW (Fig. 3) and CL/CW (Fig. 4) that -parallel those mentioned above for pattern and tuberculation have -already been mentioned under the section "Ontogenetic Variation." - -The ratio of CL/PCW (Fig. 9) was used in an effort to show further -differences in the shape of the carapace, especially the plane on the -carapace where the greatest width occurs. Figure 9 shows the greatest -width to be approximately midway between the anterior and posterior -ends in the subspecies _spinifer_, _hartwegi_ and _asper_, and in the -species _ferox_ and _muticus_ (CL/PCW of 2.00). The greatest width of -carapace is more posterior and at approximately the same plane in -_pallidus_ and _guadalupensis_, and farther posterior in _emoryi_. -Calculated ratios for 12 specimens of _T. ater_ average 2.15, a value -that suggests closer affinity with _pallidus_, _guadalupensis_ and -_emoryi_ than to the other species and subspecies. - -Comparison of the relative lengths of snout (HW/SL, Fig. 10) in -different populations of _T. spinifer_ shows a character gradient. To -facilitate a comparison utilizing large samples, the subspecies -_spinifer_ was combined with _hartwegi_, and _pallidus_ with -_guadalupensis_. The snout is longer in the subspecies _spinifer_ and -_hartwegi_ than in _emoryi_; the length of the snout of _emoryi_ -resembles that of _T. ferox_. The snout is proportionately the longest -in _T. muticus_. The average ratio of HW/SL for 12 individuals of _T. -ater_ is 1.37, and is nearer that of _pallidus_, _guadalupensis_, -_emoryi_ and _ferox_ than that of _muticus_ or the other subspecies of -_T. spinifer_. - - [Illustration: FIG. 10. Ratio of width of head to length of snout - (HW/SL) in some American species and subspecies of the genus - _Trionyx_. Symbols as in Fig. 3. Values for _spinifer_ are - combined with those of _hartwegi_, and those of _pallidus_ - with _guadalupensis_. The snout is proportionately the - longest in _muticus_.] - -Size of the ocelli increases from west to east in populations of _T. -spinifer_ in the upper Mississippi River and Great Lakes drainages. - -The ratio of OD/PL (Fig. 11) varies considerably but gradually -increases from Kansas northeastward to Michigan. The minimal diameter -of any ocellus recorded was one millimeter; solid dots on the carapace -(_hartwegi_) were also recorded as one millimeter. Larger ratios are -usually derived from measurements of larger individuals. Seemingly, -there should be a clinal tendency in ontogenetic variation paralleling -the size of ocelli and dependent on it; ontogenetic variation should -be least in western populations in which the size of ocelli does not -change appreciably with increasing size, and should be greatest in -eastern populations in which the ocelli on adult males are larger than -those on the carapace of young turtles. It is difficult to -demonstrate ontogenetic variation because specimens of corresponding -size from the same general area may have ocelli of different sizes. -The gradient in size of ocelli is also indicated by specimens from -other states. I have the subjective impression that there is least -variation in specimens from Michigan (Great Lakes-St. Lawrence River -drainage), but this is not clearly shown by Figure 11. - - [Illustration: FIG. 11. Ratio of diameter of ocellus to length of - plastron (OD/PL) in _T. spinifer_ from some states in the upper - Mississippi River and Great Lakes drainages. Symbols as in - Fig. 3. The size of the ocelli on the carapace gradually - increases from Kansas northeastward to Michigan.] - - -Character Analysis - - -_Snout_ - -The snout (Fig. 12) is tubate having terminal nostrils separated by a -vertical septum. One of the principal characters distinguishing _T. -ferox_ and _T. spinifer_ from _T. muticus_ is a lateral, whitish ridge -projecting from each side of the nasal septum (hereafter referred to -as septal ridges but often referred to in the literature as a -papilla). The shape of the end of the snout is truncate in _T. ferox_ -and _T. spinifer_, and the nostrils are larger than in _T. muticus_. -In _muticus_ the snout usually terminates somewhat obliquely, and the -nostrils tend to be slightly inferior; also, the end of the snout is -usually rounded and somewhat pointed, causing the nostrils to be -visible in lateral view. Some _T. muticus_ do not differ markedly from -_ferox_ or _spinifer_ in shape of the end of the snout. Stejneger -(1944:14) mentioned indication of a septal ridge that did not reach -the opening of the nostril in _muticus_. I have slit the outer edge of -the nostril on several specimens of _muticus_, and have not noticed an -indication of a septal ridge. - - [Illustration: FIG. 12. Shape of snout in _T. spinifer_ (left, a-d, - from KU 46907) and _T. muticus_ (right, e-h, from KU 48236). - Lateral views--a, e (× 1); anterior views--b, f (× 5); dorsal - views--c, g (× 2.5); ventral views--d, h (× 2.5).] - - -_Tuberculation_ - -Tubercles or obtuse prominences occur on the anterior edge of the -carapace (Fig. 8) or on the dorsal surface of the carapace. _Trionyx -muticus_ lacks tubercles, although some individuals show shallow, -widely spaced wrinkles that suggest prominences on the anterior edge -of the carapace. Both sexes of _T. ferox_ have prominences, resembling -flattened hemispheres, on the anterior edge of the carapace and in the -nuchal region. Large females of _ferox_ have obtuse prominences in the -center of the carapace posteriorly, some of which are often arranged -in longitudinal rows. The surface of the carapace in both sexes of _T. -ferox_ has small closely-set, blunt tubercles arranged in rows that -resemble longitudinal ridges (most evident in juveniles). - -Large females of _T. spinifer_ have obtuse prominences in the center -of the carapace posteriorly, some of which in many specimens are -arranged in longitudinal rows; I cannot discern any correlation of -number or arrangement of prominences with size in _spinifer_ or -_ferox_. The carapace in adult males of _spinifer_ bears small, sharp -tubercles that make the surface feel like sandpaper. The tubercles on -the anterior edge of the carapace in adults of both sexes vary from -round to equilateral and conical to low and flattened (see comments on -tuberculation under subsection entitled "Geographic Variation"). Some -large females of the same subspecies have tubercles on the anterior -edge of the carapace that may be conical (higher than wide) or -equilateral. The difference in shape of the tubercles seems not to be -correlated with size because one _T. s. pallidus_, 30.5 centimeters -(TU 13212) has prominent but blunted and equilateral tubercles, -whereas, another female of _pallidus_, 20.8 centimeters (TU 13210), -from the same locality has higher, conical tubercles. The blunted, -equilateral tubercles may be the result of environmental wear, or the -difference in shape of tubercles may be due to individual variation. - - -_Pattern on Carapace_ - -Two features of the pattern on the carapace are of taxonomic worth: 1) -the width and distinctness of the pale rim at the periphery of the -carapace (marginal rim), if present, and 2) the kind of pattern on the -carapace (juvenal pattern). The marginal rim is absent in females of -_T. ater_, and only faintly evident in males. The marginal rim is -obscured or absent (adult males and females) and is not separated from -the ground color of the carapace by a dark marginal line in hatchlings -of _T. ferox_. The carapace of _T. muticus_ has a marginal rim that is -usually separated from the ground color of the carapace by an -ill-defined, dark marginal line; some individuals lack the marginal -dark line. The subspecies of _T. spinifer_ have a well-defined, dark, -marginal line that separates the marginal rim from the ground color of -the carapace; _T. s. asper_ has more than one dark marginal line on -the carapace. The marginal rim is ill-defined and blotched, or absent, -in large females of all species of _Trionyx_. - -The marginal rim is widest at the posterior end of the carapace and -lacking in the nuchal area. The width of the pale marginal rim is very -narrow, almost to the degree of being absent, in juveniles of _T. -ferox_. _T. s. emoryi_ has a pale, marginal rim that is four or five -times wider posteriorly than it is laterally, whereas posteriorly the -width of the rim in the other subspecies of _T. spinifer_ and in the -species _T. muticus_ is only two or three times wider posteriorly than -it is laterally. - -The juvenal pattern commonly consists of whitish tubercles or dots -(_T. s. emoryi_, _T. s. guadalupensis_, _T. s. pallidus_, _T. ater_), -large black ocelli (_T. s. spinifer_), small black dots and ocelli -(_T. s. hartwegi_, _T. s. asper_), large dusky spots or ocelli (_T. m. -calvatus_), or small dusky dots or short streaks and dashes (_T. m. -muticus_). Some hatchlings of _pallidus_ and _emoryi_ have a uniform -pale brown or tan carapace; hatchlings of _T. ferox_ have a -distinctive pattern (Pl. 31). Further comments and illustrations -pertaining to kind of pattern on the carapace are offered under the -accounts of species and subspecies. - - -_Pattern on Dorsal Surface of Snout (Fig. 5)_ - -_T. ferox_ has pale stripes on a dark background that unite in front -of the eyes; the dark ground color becomes paler with increasing size, -but the stripes retain thick black borders. _T. m. muticus_ has -ill-defined, pale stripes that are evident just in front of the eyes -and do not extend anteriorly to unite in front of the eyes, whereas -_T. m. calvatus_ lacks pale stripes on the snout. The kind of pattern -on the dorsal surface of the snout that is characteristic for each of -the subspecies of _T. spinifer_ has been mentioned in the discussion -of clinal variation. - - -_Pattern on Side of Head (Fig. 6)_ - -_T. ferox_ has a pale broad, postocular stripe in contact with the -orbit or not, and other pale marks on a dark background; the ground -color becomes paler with increasing size, but the stripes and other -marks retain thick black borders. _T. m. muticus_ usually has an -uninterrupted, dusky-bordered, postocular stripe, whereas _T. m. -calvatus_ (in adult males only) has pale postocular stripes with thick -blackish borders. The pattern on the side of head that is -characteristic for each subspecies of _T. spinifer_ has been mentioned -in the discussion of clinal variation. - - -_Pattern on Dorsal Surface of Limbs (Fig. 7)_ - -Young specimens of _T. ferox_ have pale marks on a blackish -background. As growth proceeds the distinctive contrasting pattern is -obliterated and eventually is replaced by a uniform grayish coloration -in large adults. The pattern on the limbs of _T. muticus_ is not -contrasting, and is almost a uniform grayish, consisting of fine, pale -markings. The clinal variation in pattern and kind of pattern on the -limbs of the subspecies of _T. spinifer_ has been mentioned in the -discussion of clinal variation. Dark markings tend to form streaks -that are coincident with the digits, and larger markings occur on the -hind limbs than on the forelimbs. - - -_Marginal Ridge_ - -The anterolateral edge of the carapace in _T. ferox_ (both sexes and -all sizes) is "folded over" into a ridge having a distinct inner -margin (Pls. 1 and 2), which is hereafter referred to as the marginal -ridge. Siebenrock (1924:184-85) referred to this ridge as a -"Hautsäume" and mentioned its occurrence in Old World species of the -genus _Trionyx_. The marginal ridge is not present in _T. muticus_, -_T. spinifer_ or _T. ater_. - - -_Ratios_ - -The means of some samples (Fig. 3) differ in regard to PL/HW, but the -ranges of variation overlap so much that little significance can be -attributed to the difference. _T. ferox_, and to a lesser extent _T. -s. emoryi_ and _T. s. asper_, have slightly larger heads than the -other forms. The width of head is proportionately the smallest in _T. -muticus_; in most individuals of it having a plastron so long as 13.0 -centimeters, the width of the head is less than 16 per cent of the -length of the plastron--a percentage that is distinctive. - -The visibly narrower carapace (CL/CW, Fig. 4), suggesting an ovoid or -oblong shape, in some large individuals of _T. ferox_ and _T. s. -emoryi_ is indicated by the large ratio in specimens that have a -plastral length of 8.0 centimeters or more. Nevertheless, the degree -of overlap of the ranges of variation is such that this ratio is of -relatively little use taxonomically. - -The greatest width of the carapace is farther posterior in _T. s. -emoryi_ than in the other forms (CL/PCW, Fig. 9). The considerable -overlap of the range of variation of this ratio for _emoryi_ with the -other forms limits its usefulness as a taxonomic character. - -The snout is proportionately shortest in _ferox_ and _T. s. emoryi_, -and longest in _muticus_ (HW/SL, Fig. 10). The most marked difference -in this ratio is between the species _muticus_ and _ferox_; the ranges -of variation of those species overlap to a degree that tends to negate -the taxonomic usefulness of this character. - -Most adults and subadults of _T. ferox_ show clearly in dorsal view -the anterolateral portions of the plastron. This condition is much -less well developed in some specimens of _T. s. emoryi_. _T. ferox_ is -extreme in the ratio CL/PL (relatively the longest plastron or -shortest carapace, Fig. 13). _T. s. asper_ has the shortest plastron -in relation to length of carapace. Calculated ratios for 12 _T. ater_ -average 1.36, a value that suggests close affinity with some -subspecies of _T. spinifer_ (_pallidus_, _guadalupensis_, _emoryi_). -Because of the degree of overlap of the ranges of variation in all -forms, little significance can be attributed to the difference in -means of _ferox_ and _asper_. - - [Illustration: FIG. 13. Ratio of length of carapace to length of - plastron (CL/PL) in some American species and subspecies of - the genus _Trionyx_. Symbols as in Fig. 3. _T. ferox_ has - proportionately the shortest carapace.] - - -_Scalation_ - -Cornified, smooth or cusplike areas occur on each limb, but their -number and arrangement are of no taxonomic value. Normally, the -anterior surface of each forelimb possesses four cornified areas for -which the term antebrachial scales is proposed (Fig. 14). Two of the -four scales occur in a more dorsal position; the lateral edge of the -proximal one is free and cusplike along a part of its length, whereas -the distal scale is smooth-edged. Two scales having their lateral -edges free and cusplike are ventral in position, and closer together -than the two dorsad scales. Size of the scales and length of the free -cusplike edges vary. Occasionally adjacent scales are fused or small -additional scales are present. The number, configuration and -arrangement of the two cornified areas on each hind limb are constant. -One of these scales is smooth-edged and occurs posteriorly on the -dorsal surface. The other scale, situated on the ventral surface -posteriorly in the region of the heel and distal to the smooth-edged -scale of the dorsal surface, has a pronounced, cusplike, free edge. - - [Illustration: FIG. 14. Dorsal surface of right forelimb showing - normal number and arrangement of antebrachial scales in American - species of the genus _Trionyx_ (_T. spinifer hartwegi_, - KU 15932, × 3/4).] - - -_Choanal Papillae_ - -This term refers to the papillate flaps of skin that project from the -lateral borders of the internal nares. Webb and Legler (1960:23) noted -their presence in softshells, and Parsons (1958) discussed their -occurrence in sea turtles of the family Cheloniidae and in the -testudinid subfamily Emydinae (1960). In preserved softshells the -choanal papillae may extend laterally and partly cover the nares, or -may be folded vertically against the lateral borders of the nares; in -the latter position the papillae are easily overlooked. To my -knowledge, choanal papillae occur in all American species and -subspecies of soft-shelled turtles. The free edge of each narial flap -shows various degrees of fimbriation. The fimbriated border is least -developed (margin nearly entire) in _T. muticus_ and most developed in -_T. ater_ and _T. ferox_. In _ater_ at least, the anteriormost -portions of the narial flaps seem wider than in the other forms and -show a greater degree of fimbriation than the posteriormost parts. The -choanal papillae are most easily observed in large specimens. - - -_Skull_ - -In general, there is less difference between the skulls of _ferox_ and -_spinifer_ than between either of those species and _muticus_ -(Stejneger, 1944:10-11). Figure 15 shows the general differences in -proportions of the skulls of _spinifer_ and _muticus_; Plate 54 shows -the skull of the holotype of _Platypeltis agassizi_ (= _T. s. asper_), -which is similar to that of _ferox_; Stejneger (_op. cit._) provided -labelled drawings of the skull of _T. spinifer_ as well as photographs -of skulls of other forms. - -The total of 159 skulls examined by me include 80 of _spinifer_, 50 of -_ferox_, and 29 of _muticus_. There are no secondary sexual -differences between skulls of corresponding size, except in -_agassizi_-form skulls mentioned under the account of _T. s. asper_, -and possibly in _ferox_. Most, and possibly all, of the skulls of -_muticus_ having a basicranial length of 40.0 millimeters or more, and -those of _spinifer_ exceeding 50.0 millimeters must represent females -(by correlation of known maximum size of males with greatest width of -head, which is, in turn, compared with the greatest width of skull and -corresponding basicranial length). - - [Illustration: FIG. 15. Skulls of _Trionyx spinifer hartwegi_ (left, - a-d, KU 2757), and _Trionyx muticus muticus_ (right, e-h, KU 1870). - Dorsal views, a (× 1/2), e (× 3/4); occipital views, b (× 5/6), - f (× 1); lateral views, c (× 1/2), g (× 3/4); ventral views, - d (× 1/2), h (× 3/4). - - a., alveolar surface of upper jaw - aq., articular surface of quadrate - ex., exoccipital - fp., fenestra postotica - fm., foramen magnum - if., intermaxillary foramen - ic., internal choana - mx., maxilla - mxb., maxillary bridge - oc., occipital condyle - op., opisthotic - ope., opisthotic-exoccipital spur - opw., opisthotic wing - pmx., premaxillaries (fused) - pt., pterygoid - q., quadrate - qj., quadratojugal - sq., squamosal - s., supraoccipital spine - tc., tympanic cavity - ] - -Measurements used include basicranial length (occipital condyle to tip -of upper jaw), greatest width (variable in position), greatest width of -alveolar surface of maxilla (taken at level immediately posterior to -anterior margin of internal choanae), greatest length of internal -choanae, and least breadth of maxillary bridge (separating internal -choanae and intermaxillary foramen). One ratio developed from the -measurements was greatest length of internal choanae/least breadth of -maxillary bridge, hereafter referred to as IC/MB. This ratio is -discussed under the account of _T. s. asper_. - - -_Greatest Width_ - -The position or level on the skull where the greatest width (Table 3) -occurs is of some diagnostic value in distinguishing the skulls of -_ferox_ from _spinifer_ and _muticus_. Skulls of _ferox_ usually are -widest at the level of the quadratojugal (immediately in front of -tympanic cavity), whereas skulls of _spinifer_ and _muticus_ usually -are widest slightly more posteriorly at a level on the squamosal -immediately behind the tympanic cavity. Occasionally the width at the -level of the quadratojugal and squamosal is the same, or the greatest -width of skull may be ventrad between the quadrates, which are -slightly flared laterally. The latter condition possibly is most -prevalent in _muticus_. - - TABLE 3. Variation in Position of Greatest Width of Skull of North - American Species of the Genus Trionyx (excluding ater). The Number - of Specimens Examined (in Parentheses) Follow the Specific Names. - - ================+================================================= - | Species - POSITION +--------------+-----------------+---------------- - | _ferox_ (36) | _spinifer_ (47) | _muticus_ (14) - ----------------+--------------+-----------------+---------------- - Squamosal | 7 (19%) | 35 (74%) | 11 (79%) - Quadratojugal | 26 (72%) | 7 (15%) | 1 (7%) - Quadrate | 2 (6%) | | 2 (14%) - Squamosal and | | | - quadratojugal | | | - of same width | 1 (3%) | 5 (11%) | - ----------------+--------------+-----------------+---------------- - - -_Supraoccipital Spine_ - -The ventral surface of the supraoccipital spine in _muticus_ lacks a -medial ridge, and gradually increases in width anteriorly, so that it -is widest proximally in the region of the roof of the foramen magnum. -In _ferox_ and _spinifer_, the ventral surface, usually having a -medial ridge, is narrow and of the same width throughout its length or -somewhat flared distally. The ventral surface of the supraoccipital -spine, which is widest proximally in _muticus_, is always narrow -proximally in _ferox_ and _spinifer_. The ventral surface of the -supraoccipital spine of one skull of _spinifer_, USNM 91311, differs -little from that of _muticus_. - - -_Foramen Magnum_ - -The shape of the foramen magnum is generally rhomboidal in _spinifer_ -and _ferox_; the ventral angle is semicircular, the lateral angles -obtuse, and the dorsal angle more acute. The shape of the foramen -magnum in _muticus_ is ovoid, higher than wide; the sides are evenly -rounded. - - -_Opisthotic-Exoccipital Spur_ - -Skulls of _spinifer_ normally have the fenestra postotica partly -restricted by a medially-slanting, descending spur from the roof of -the fenestra postotica; the spur incorporates the suture between the -exoccipital and opisthotic and includes parts of those two bones. On -one skull (KU 2824) the spur is displaced more medially and does not -incorporate the opisthotic. The descending spur contacts the pterygoid -ventrally forming a complete bony strut traversing the fenestra -postotica in some skulls (KU 2228, 2666, 2762, TU 15423, MCZ 46621, TU -15415, right side only). The fenestra postotica on skulls of _ferox_ -and especially _muticus_ is not normally restricted by an -opisthotic-exoccipital spur. - -Often the spur is reduced and indicated by a smooth projecting ridge. -Sometimes the spur or ridge is absent on skulls of _spinifer_, and I -have seen no well-developed spur on a skull of _muticus_. The -development of the spur is not due to ontogenetic variation. There is -some variation in development of the spur on either side of the skull; -two skulls of _ferox_ have the combination ridge/absent, and two of -_spinifer_ have the combinations ridge/spur and spur/absent. The -frequency (based on counts of individual skulls) and the degree of -development of the spur among the three species is indicated in Table -4. - - TABLE 4. Frequency and Degree of Development of Opisthotic - Exoccipital Spur of North American Species of the Genus Trionyx - (excluding ater). The Number of Specimens Examined (in Parentheses) - Follow the Specific Names. - - ======================+================================================= - | Species - DEVELOPMENT OF SPUR +--------------+-----------------+---------------- - | _ferox_ (43) | _spinifer_ (68) | _muticus_ (29) - ----------------------+--------------+-----------------+---------------- - spur (well-developed) | 1 (2%) | 45 (66%) | - ridge (reduced) | 7 (16%) | 20 (30%) | 1 (3%) - absent | 35 (82%) | 3 (4%) | 28 (97%) - ----------------------+--------------+-----------------+---------------- - -Loveridge and Williams (1957:415, footnote) cited Siebenrock who -mentioned a descending process of the opisthotic in _Dogania_ (= -_Trionyx_) _subplana_ and _Trionyx sinensis_. I have not seen an -ascending process of the pterygoids on skulls of American softshells -as described by Loveridge and Williams (_op. cit._:414, 429, fig. 54) -for _Lissemys_, _Cyclanorbis_, _Cycloderma_ and some _Trionyx -triunguis_. - - -_Opisthotic Wing_ - -This term refers to the laterally directed, posterior part of the -opisthotic that is visible in occipital, lateral and ventral views. In -ventral view the opisthotic wing is most easily seen and is wider in -_muticus_ than in _spinifer_ or _ferox_. In _muticus_ the distal part -is truncate, whereas in _ferox_ and _spinifer_, it is more tapered and -gently rounded, although somewhat unevenly flared medially. Also -there is more of a downward curvature (in ventral view) of the -opisthotic wing in _muticus_ than in _ferox_ or _spinifer_; -consequently the tip of the wing in _muticus_ is often just visible in -dorsal view (on lateral side of squamosal), certainly in lateral view. -The distal part or tip of the opisthotic wing is not visible in dorsal -view on skulls of _ferox_ or _spinifer_. - - -_Articular Surface of Quadrate_ - -The ventral surface of the quadrate that articulates with the mandible -is composed of a lateral condyle and a medial articular surface. The -condyle and medial articular surface are separated by a furrow. On -skulls of _ferox_ and _spinifer_ the lateral condyle, which is not -conspicuously tapered posteriorly, is slightly larger than the medial -articular surface, and the furrow is shallow. On skulls of _muticus_, -the lateral condyle is conspicuously tapered posteriorly, is slightly -smaller than the medial articular surface, and the furrow is deep. - - -_Contact of Maxillaries Above Premaxillaries_ - -The contact of the maxillaries above the premaxillaries is of -diagnostic value in distinguishing skulls of _ferox_ and _spinifer_ -from those of _muticus_. I have seen no skulls of _muticus_ on which -the maxillaries were in contact, and no skulls of _ferox_ on which the -maxillaries were separated. Stejneger (1944:19), however, reported a -skull of _muticus_ (USNM 102677) having the maxillaries in contact. -Maxillaries are in contact (sometimes just barely) in 65 of 74 skulls -of _spinifer_ (88%); the premaxillaries are separated on nine skulls -(12%). - - -_Carapace_ - -The dorsal surface of the bony carapace of American trionychids -consists of a nuchal, seven or eight pairs of pleurals, and seven or -eight, rarely nine, neurals (Fig. 16). The lateral parts of the nuchal -overlie the second pair of ribs. The distal parts of the second -through the ninth pair of ribs extend laterally beyond the lateral -edges of the pleurals. There are no marginal ossifications. The -posterior part of the bony carapace bears blunt, rounded or ovoid to -linear, prominences mostly on the last pair of pleurals principally on -large females of _spinifer_ and _ferox_; I have seen only one adult -male (stuffed, MCZ 46633) having a semblance of welts on the bony -carapace. The nuchal, pleurals and neurals are sculptured. - -As growth proceeds, the single, transversely-oriented, fontanelle of -young turtles that separates the nuchal from the first neural and -first pair of pleurals divides into two fontanelles that generally -decrease in size and finally disappear. Occasionally only one -(unilateral) large fontanelle is present (USNM 54734, _muticus_). The -largest specimens noted that retain fontanelles are a _ferox_ (USNM -029474) having a plastron 24 centimeters long, and a _spinifer_ (USNM -54731) having a plastron 20 centimeters long. The fontanelles probably -are present in some larger individuals. - - [Illustration: FIG. 16. Carapace of _Trionyx spinifer_ (a), and - sketches of posterior parts of carapaces (b-i) of three American - species, showing number and variation in arrangement of neurals and - pleurals (not to scale; seventh neural, n7, and pleural, p7). - - a. KU 2226, Lewisville, Lafayette County, Arkansas (× 1/3); - sculpturing incompletely shown. Labels: r, ribs; nu, nuchal; n, - neurals 1-7; p, pleurals 1-7. - - b. _ferox_, USNM 60496, Auburndale, Polk County, Florida. - - c. _muticus_, KU 1964, Doniphan Lake, Doniphan County, Kansas. - - d. _spinifer_, USNM 100380, Plaquemine, Iberville Parish, - Louisiana. - - e. _muticus_, TCWC 7260, Red River, 8 mi. NW Ringgold, Montague - County, in Clay County, Texas. - - f. _spinifer_, USNM 59266, Homer, Winona, Minnesota. - - g. _muticus_, KU 2840, White River, DeValls Bluff, Prairie County, - Arkansas. - - h. _muticus_, USNM 115939, Mississippi. - - i. _muticus_, USNM 54734, Mississippi River, Fairport, Muscatine - County, Iowa. - ] - -Most variation concerns the number of neurals and pairs of pleurals, and -their arrangement posteriorly (H. M. Smith, 1947:121, table; Stejneger, -1944:18). Table 5 shows the frequency of occurrence of the number of -neurals, pairs of pleurals, and the separation or contact of the seventh -pair of pleurals; figure 16 illustrates some of the configurations of -these plates posteriorly (e, g, and i not included in Table 5). The -eighth pair of pleurals is reduced or absent (Loveridge and Williams, -1957:417). Eight neurals and eight pairs of pleurals occur in all three -species. The seventh pleurals may contact each other in all three -species, and their separation has been observed only in the species -_spinifer_ and _muticus_. Seven neurals and contact of the seventh pair -of pleurals, or eight neurals and separation of the seventh pair of -pleurals from each other occurs with approximately equal frequency in -the species _muticus_. _T. ferox_ and _spinifer_ most often have seven -neurals, seven pairs of pleurals, and the seventh pair of pleurals in -contact. Stejneger (_loc. cit._) mentioned a specimen in MCZ having nine -neurals; I recorded nine neurals for USNM 54734 (Fig. 16i) for which -Stejneger (_loc. cit._) recorded eight. AMNH 57384 (_ferox_) has a small -eighth pleural on the left side only, and USNM 115939 (_muticus_) has an -eighth pleural only on the right side (Fig. 16h). Anomalous conditions -observed included: an accessory bone between the first and second -pleurals on the right side that contacts the first and second neurals in -USNM 54733, (_muticus_); only six neurals in USNM 95193 (_spinifer_); a -small accessory bony element between the first and second neurals in -AMNH 57383 (_ferox_); and, only six pleurals (second and third fused) on -the right side in USNM 54734 (_muticus_). - - TABLE 5. Frequency of Occurrence of Number of Neurals, Pairs of - Pleurals, and Separation or Contact of the Seventh Pair of - Pleurals Among Species of American Soft-shell Turtles - - ===================+=================+================================== - Number | Contact (+) or | Species - --------+----------+ separation (-) +---------+------------+----------- - | Pairs of | of seventh pair | _ferox_ | _spinifer_ | _muticus_ - Neurals | pleurals | of pleurals | (16) | (60) | (34) - --------+----------+-----------------+---------+------------+----------- - 7 | 7 | + | 9 (56%) | 50 (83%) | 13 (38%) - 7 | 8 | + | 5 (31%) | 2 (3%) | 2 (6%) - 8 | 7 | + | 2 (13%) | 3 (5%) | 3 (9%) - 8 | 8 | + | | 4 (7%) | 2 (6%) - 8 | 7 | - | | 1 (2%) | 14 (41%) - --------+----------+-----------------+---------+------------+----------- - -Ventrally, the bony carapace shows ten thoracic vertebrae, the second -through the ninth having well-developed, depressed ribs that are fused -(no sutures) to the pleurals. The ribs of the first thoracic vertebra -are represented by bony struts that extend posterolaterally and -contact the anterior borders of the second pair of ribs. The two ribs -of the ninth pair are free for most of their length and often are -broken; they are slightly shorter than the eighth pair of ribs. The -ribs of the tenth thoracic vertebra may be well-developed (KU 2219, -2666, 50856, _spinifer_, and 16528, _ferox_), but are usually broken -off and represented only by transverse processes. - - -Kyphosis - -Kyphosis (angular curvature of the vertebral column) or the -hump-backed condition in American softshell turtles has been -summarized by Nixon and Smith (1949:28). Cahn (1937:185, pl. 25e) -illustrated the condition in an individual of _T. spinifer_, and H. -M. Smith (1947:119) mentioned kyphotic softshells representing the -species _spinifer_ (subspecies _hartwegi_ and _emoryi_) and _muticus_. -Neill (1951:10) mentioned two kyphotic _T. s. asper_ and Nixon and -Smith (_loc. cit._) recorded the report of a kyphotic _T. ferox_. I -have noted the condition in four _muticus_ (subspecies _muticus_, KU -1959-60, 23230; INHS 2148) and seven _spinifer_ (CNHM 22925; -subspecies _hartwegi_, USNM 55689; subspecies _spinifer_, UMMZ 52948, -95615; subspecies _emoryi_, KU 2219, 33523, TU 16240). The smallest -kyphotic specimen, a hatchling, TU 16240, has a plastral length of 3.5 -centimeters. Kyphosis is to be expected in all kinds of softshells as -are other abnormalities, such as albinism (reported for _Lissemys_ by -D'Abreu, 1928, and partial albinism noted in _T. cartilagineus_ by -Mohr, 1929) or congenital absence of limbs (reported by Dutta, 1931, -as occurring in the genera _Trionyx_ and _Lissemys_). The cause of -kyphosis is not known. Smith (_op. cit._:120) suggested an abnormally -early fusion of the costals (= pleurals) with the ribs, and a -subsequent differential rate of growth between them and the vertebral -column as a hypothesis; Williams (1957:236) proposed that late -retraction of the yolk mass, or retraction of an excessively large -yolk mass may cause kyphosis. The cause of kyphosis may be of genetic -origin or due to some environmental damage to the vertebral column -prior to the cessation of growth. The variation in rate of growth of -the vertebral column may produce humps of different shapes and sizes. -Some of the specimens noted above (UMMZ 52948, 95615) have the -carapace only slightly arched and are considered partly kyphotic. -There seem to be degrees of kyphosis, a fact that should be taken into -account in considering the occurrence of variation in greatest depth -of shell. - - -Plastron - -The plastron is united to the carapace by ligamentous tissue and is -somewhat flexible anteriorly and posteriorly. Anteriorly the plastron -is somewhat hingelike and may contact the anteriormost edge of the -carapace. The bony elements are reduced. There is usually a median -vacuity, which is relatively smaller in larger specimens and may be -divided into two vacuities (a posteromedial and an anteromedial) by -the medial juxtaposition of the hyo-hypoplastra, especially in -_muticus_. Williams and McDowell (1952) have recommended a change in -nomenclature for some of the plastral bones on the basis of -reinterpretation of their homologies. The nine plastral bones include: -an anterior pair of preplastra (= epiplastra, _auct._); an unpaired, -median bone, representing fused epiplastra (= entoplastron, _auct._), -hereafter referred to as the epiplastron; a pair of hyoplastra; a pair -of hypoplastra; and, posteriorly, a pair of xiphiplastra (Fig. 17). - -Siebenrock's (1902) synopsis of living trionychids was based entirely -on plastral characters. He distinguished between _muticus_ and -_spinifer_ principally by the shape of the epiplastron; _T. ferox_ was -not considered different from _spinifer_. The median angle formed by -the boomerang-shaped epiplastron is obtuse and somewhat greater than -90 degrees in _muticus_ (Fig. 17a); the angle of the epiplastron in -_spinifer_ and _ferox_ is smaller than in _muticus_ and forms an -approximate right angle (Fig. 17b). Williams and McDowell (_op. -cit._:277, Pl. 1, Fig. 3) presented an illustration of the anterior -plastral elements of an adult _T. ferox_. Siebenrock provided -illustrations of the plastrons of _muticus_ (_op. cit._:823, Fig. 5) -and _spinifer_ (_op. cit._:830, Fig. 10). - - [Illustration: FIG. 17. Plastron of _Trionyx muticus_ (a) and _T. - spinifer_ (b); sculpturing of callosities incompletely shown. ep, - epiplastron; hp, hyoplastron; hyp, hypoplastron; pp, preplastron; - xp, xiphiplastron. a--KU 1868, White River, Devall's Bluff, Prairie - County, Arkansas (× 2/3); b--KU 1869, same locality (× 2/3).] - -Much importance has been credited to the fusion (no suture) or -separation (suture present) of the hypoplastra and hyoplastra. The -fusion of these bones distinguishes the genera _Lissemys_, _Cyclanorbis_ -and _Cycloderma_ from _Trionyx_, _Pelochelys_, and _Chitra_ (Siebenrock, -_op. cit._:815, 817; Loveridge and Williams, 1957:415). This character -is also one of the criteria used by Hummel (1929: 768) in his erection -of the two subfamilies Cyclanorbinae (= Lissemyinae) and Trionychinae. -In my examination of specimens this character, unfortunately, was not -given full attention. I have noted the fusion of the hypoplastra and -hyoplastra in KU 1878 (_muticus_, right side only), KU 2219 (kyphotic -_spinifer_), KU 16528 (_ferox_) and KU 60121 (_ferox_). Dr. Ernest E. -Williams informs me in a letter of November 17, 1959, that of six -specimens of _ferox_ in the MCZ, the hyoplastra are fused with the -hypoplastra in three (54689-90, 54686). I suspect that these bones in -the three American species of the genus _Trionyx_, especially in -_ferox_, fuse more often than is supposed. - -In _muticus_ the constricted part of the hyoplastron and hypoplastron is -wider anteroposteriorly than in _spinifer_ or _ferox_ (Fig. 17). - -The three American species have on the hyoplastra, hypoplastra, and -xiphiplastra well-developed callosities, which enlarge with increasing -size. The medial borders of the hyoplastral and hypoplastral callosities -in larger specimens are rounded and closely approximated, often -touching, as do the callosities of each xiphiplastron; seemingly, the -callosities are relatively larger in _muticus_ than in _spinifer_ and -_ferox_. I have seen one adult male _muticus_ (KU 41380) that lacked -median fontanelles or vacuities owing to the contact of the plastral -elements (as viewed through overlying skin, alcoholic specimen). The -bony plastron (approximately 9 cm. in maximal length) of a small -_muticus_ (KU 19460) resembles the plastron of larger individuals of -_muticus_ in having well-developed hyoplastral and hypoplastral -callosities that are closely approximated medially. Large individuals of -_muticus_ usually have small, ovoid callosities on the preplastra, and a -well-developed, angular callosity on the epiplastron (Fig. 17a). -Siebenrock (_op. cit._:823) suggests that the presence of callosities on -the preplastra and epiplastron of _muticus_ is subject to individual -variation. I can not substantiate or dispute the supposition of Baur -(1888:1122), Siebenrock (1924:193) and Stejneger (1944:12, 19) that the -callosities are larger in males of _muticus_ than in the females. Some -individuals of _spinifer_ have seven plastral callosities (KU 2842) as -does _muticus_, but the callosities on the preplastra and epiplastron -are less frequent and less well-developed in large specimens of -_spinifer_ than in _muticus_. The small epiplastral callosity in -_spinifer_ is located at the medial angle and does not extend -posterolaterally to cover the entire surface of the epiplastron as it -may in _muticus_ (Fig. 17b). The epiplastron of a _spinifer_ (KU 2826) -has a medial callosity and another on the right posterolateral -projection; three separate callosities occur on the epiplastron of MCZ -46615. The last specimen mentioned, a large, stuffed female, possesses a -round, intercalary bone that tends to occlude the posteromedial vacuity. -Seemingly, the callosity on the epiplastron appears prior to those on -the preplastra; I have not seen any plastra having callosities on the -preplastra and lacking a callosity on the epiplastron. I have not noted -callosities on the preplastra or epiplastron of specimens of _ferox_. - -The callosities on the plastral bones are sculptured; small, recently -formed callosities on the preplastra and epiplastron lack sculpturing. -The pattern of sculpturing on the plastral bones as well as that of the -carapace is generally of anastamosing ridges. I am unable to discern any -differences in pattern of sculpturing between the three American -species. Stejneger distinguished adult specimens of _ferox_ from the -other American species by the coarseness of the sculpture of the bony -callosities (1944:24) and of the bony carapace (_op. cit._:32). The -sculpturing on the plastral callosities and carapace seems to be -correlated with size; larger specimens (_ferox_) have coarser -sculpturing than do smaller specimens (_muticus_). Stejneger also -mentioned that the sculpturing on many specimens of _ferox_ is -specialized into prominent, longitudinal welts (_loc. cit._); these -welts occur also on the carapace of _spinifer_. - -On the basis of the osteological characters examined by me, _T. muticus_ -is distinguished from _spinifer_ and _ferox_ by a number of characters -(plastron and especially skull) whereas the species _spinifer_ and -_ferox_ are not easily distinguished from one another. - - -Composition of the Genus _Trionyx_ in North America - -Analysis of the characters previously mentioned and their geographic -distribution permits the recognition of ten taxa, comprising four -species and eight subspecies. Two subspecies, _T. spinifer_ pallidus -and _T. s. guadalupensis_ are described as new. The four species and -the included subspecies here recognized are: - - _Trionyx ferox_ - _Trionyx spinifer spinifer_ - _hartwegi_ - _asper_ - _emoryi_ - _guadalupensis_ - _pallidus_ - _Trionyx ater_ - _Trionyx muticus muticus_ - _calvatus_ - -The following key is designed to permit quick identification of living -individuals; therefore, ratios and osteological characters are avoided -as much as possible in favor of other characters that are the least -variable and most "typical." Because there is considerable variation -correlated with sex and size, each taxon occurs in the key in more -than one couplet. Large females having mottled and blotched patterns -will be the most difficult to identify. The characters listed should -be used in combination because one character alone may not be -sufficient; it is advisable to read both choices of each couplet. The -text, figures and illustrations should be consulted for final -identification. - - - - -ARTIFICIAL KEY TO NORTH AMERICAN SPECIES AND SUBSPECIES OF THE GENUS -TRIONYX - - 1. Septal ridges present; tubercles on anterior edge of - carapace present or absent 2 - - Septal ridges absent; anterior edge of carapace lacking - tubercles or raised prominences 19 - - 2. Plastral area a uniform dark slate or blackish; soft - parts of body blackish having large pale marks dorsally; - carapace having large black blotches, often fused along - margin, on pale background, and many well-defined - longitudinal ridges _ T. ferox_, p. 479 - - Combination of characters not as above; ventral - surface whitish, blackish flecks or blotches - sometimes present 3 - - - 3. Carapace having pattern of white dots, or black ocelli - and/or spots; carapace sometimes gritty resembling - sandpaper 4 - - Carapace uniform pale brownish or grayish, or having - mottled and blotched pattern, contrasting or not; white - dots or tubercles, black ocelli and/or spots may be - present; carapace not gritty 10 - - 4. Carapace having pattern of black ocelli and/or spots; - numerous, conspicuous whitish spots or tubercles absent 5 - - Carapace having pattern of white dots that are sometimes - surrounded by small black ocelli; small black dots may be - interspersed among larger white dots 7 - - 5. Carapace having two or more marginal lines, these often - diffuse and interrupted; black spots sometimes ocellate - or bacilliform, or interspersed among smaller black dots; - postocular and postlabial stripes usually united - _spinifer asper_, p. 502 - - Carapace having only one dark marginal line; pattern of - black ocelli or spots; postocular and postlabial stripes - usually not united 6 - - 6. Carapace having prominent ocelli, which are much larger - near the center than at the sides - _spinifer spinifer_, p. 489 - - Carapace having numerous small, dark spots, sometimes - small ocelli, which are not much larger near the center - than the sides _spinifer hartwegi_, p. 497 - - 7. White spots on anterior third of carapace; white spots - on carapace often surrounded by narrow blackish ocelli; - small black dots sometimes interspersed among white spots - _spinifer guadalupensis_, p. 517 - - White spots absent on anterior third of carapace, or - small and inconspicuous; white spots not surrounded - by narrow blackish ocelli 8 - - 8. Pale rim of carapace narrow, partly obscured; over-all - dorsal coloration (including soft parts of body) dark and - lacking pattern; few, small, white tubercles confined to - posterior third of carapace _ater_, p. 528 - - Pale rim distinct, without markings; soft parts of body - dorsally not uniformly dark; many white tubercles - usually contrasting on pale carapace 9 - - 9. White spots confined to posterior third of carapace; - ground color of carapace usually pale brown or tan, - sometimes darker; a dark, slightly curved, line - connecting anterior margins of orbits; postocular stripe - usually interrupted leaving pale, blotch behind eye; - pale rim of carapace four or five times wider - posteriorly than laterally _spinifer emoryi_, p. 510 - - Small white spots on posterior half of carapace gradually - decreasing in size anteriorly, often indistinct or absent - on anterior third of carapace; pale rim of carapace no - more than three times wider posteriorly than laterally - _spinifer pallidus_, p. 522 - - 10. Marginal ridge present; carapace having ill-defined - dark blotches on uniform grayish, lacking whitish - tubercles or well-defined black spots or ocelli; pale - rim of carapace absent; tubercles on anterior edge of - carapace resembling flattened hemispheres; anterior - parts of plastron often visible in dorsal view; - postocular stripe, if present, having thick, blackish - borders _ferox_, p. 479 - - Marginal ridge absent 11 - - 11. Carapace uniform pale brownish, lacking mottled and - blotched pattern, white dots, black ocelli or spots 12 - - Carapace having mottled and blotched pattern, - contrasting or not; white spots or tubercles, black - ocelli or spots may be present 13 - - 12. Pale rim of carapace four or five times wider - posteriorly than laterally; dark, straight or slightly - curved, line connecting anterior margins of orbits - _spinifer emoryi_, p. 510 - - Pale rim of carapace no more than three times wider - posteriorly than laterally _spinifer pallidus_, p. 522 - - 13. Rear margin of carapace usually roughened by fine - corrugations, edge often ragged; pale rim absent; - carapace having dark brown-blackish, mottled and - blotched pattern; anterior edge of carapace more or - less smooth having scarcely elevated prominences; - posterior part of plastral area and especially ventral - surface of carapace having numerous black marks - _ater_, p. 528 - - Rear margin of carapace smooth, edge entire; - usually some evidence of pale rim 14 - - 14. White, rounded tubercles or spots usually evident - posteriorly on carapace, sometimes indistinct; black - ocelli or spots lacking in center of carapace, - sometimes present at sides; shape of tubercles on - anterior edge of carapace variable 15 - - White spots or tubercles absent; margin of carapace - usually having black ocelli or spots; tubercles on - anterior edge of carapace equilateral or conical, - not low and flattened 17 - - 15. White spots often present on anterior half of carapace; - tubercles on anterior edge equilateral and wartlike, - or less elevated, not conical - _spinifer guadalupensis_, p. 517 - - White spots usually absent on anterior half of - carapace, sometimes indistinct; shape of tubercles - on anterior edge of carapace variable 16 - - 16. White spots absent on anterior half of carapace; - tubercles on anterior edge of carapace low, scarcely - elevated, never equilateral or conical; mottled and - blotched pattern often not contrasting; ground color of - carapace sometimes dark; pale rim of carapace four or - five times wider posteriorly than laterally; dark, - straight or slightly curved, line connecting anterior - margins or orbits _spinifer emoryi_, p. 510 - - White spots sometimes indistinct on carapace, or few, - small spots present on posterior half of carapace; - tubercles on anterior edge of carapace equilateral and - wartlike or conical; mottled and blotched pattern usually - contrasting; pale rim less than three times wider - posteriorly than laterally _spinifer pallidus_, p. 522 - - 17. Carapace having evidence of more than one dark marginal - line, and scattered, black spots or ocelli - _spinifer asper_, p. 502 - - Carapace having only one, dark, marginal line 18 - - 18. Carapace having small black spots, lacking large - interrupted ocelli _spinifer hartwegi_, p. 497 - - Carapace having small black spots interspersed among - larger, interrupted ocelli _spinifer spinifer_, p. 489 - - 19. Carapace having pattern of dusky spots, sometimes - short lines 20 - - Carapace lacking pattern of dark spots or lines, - having a mottled and blotched pattern 21 - - 20. Pattern of circular spots, lacking short lines or - bacilliform marks; spots sometimes slightly ocellate; - no pale stripes on snout _muticus calvatus_, p. 539 - - Pattern of dots, or dots and short lines; pale - stripes on snout, at least just in front of eyes - _muticus muticus_, p. 534 - - 21. Mottled and blotched pattern usually contrasting; - ill-defined, blackish blotch absent behind eye - _muticus muticus_, p. 534 - - Mottled and blotched pattern usually not contrasting; - ill-defined, dark blotch may be present behind eye - _muticus calvatus_, p. 539 - - - - -Systematic Account of Species and Subspecies - - -=Trionyx ferox= (Schneider) - -Florida Softshell - -Plates 31 and 32 - - _Testudo ferox_ Schneider, Naturg. Schildkr., p. 330, 1783 (based - on Pennant, Philos. Trans. London, 61 (Pt. 1, Art. 32): 268, - pl. 10 [figs. 1-3], 1772). - - _Trionyx ferox_ Schwartz, Charleston Mus. Leaflet, No. 26:17, - pls. 1-3, May, 1956. - - _Testudo mollis_ Lacépède, Hist., Nat. Quadr. Ovip. Serp., 1:137, - pl. 7, 1788. - - _Testudo_ (_ferox_?) verrucosa Schoepff, Hist. Testud., Fasc. 5 - (Plag. M):90, pl. 19, 1795. - - _Testudo bartrami_ Daudin, Hist. Nat. Rept., 2:74, pl. 18, fig. 2, - 1801. - - _Trionyx georgicus_ Geoffroy, Ann. Mus. Hist. Nat., Paris, 14:17, - August, 1809. - - _Mesodeca bartrami_ Rafinesque, Atlan. Jour., Friend Knowledge, - Philadelphia, 1 (No. 2, Art. 12):64, Summer, 1832. - - _Trionyx harlani_ Bell in Harlan, Medic. Phys. Research, p. 159, - 1835. - -_Type._--Holotype, British Museum (Natural History) 1947.3.6.17; original -number 53A, presumably that of Royal Society; stuffed adult female and skull; -obtained from the Savannah River, Georgia, by Dr. Alexander Garden. - -_Range._--Southern South Carolina, southeastern Georgia, and all of Florida -except the Keys and perhaps the western end of the panhandle (see map, Fig. -18). - -[Illustration: FIG. 18. Map of southeastern United States showing geographic distribution -of _Trionyx ferox_.] - -_Diagnosis._--Marginal ridge present; longitudinal rows of tubercles that -resemble ridges on carapace of hatchlings; plastron often extending farther -forward than carapace in adults; plastral area dark slate or gray in hatchlings; -juvenal pattern of large slate or blackish blotches (often with pale centers) -on a pale background; pale outer rim of carapace (absent on adults) narrow, -not separated from ground color of carapace by distinct, dark line. - -Size large; head wide; carapace relatively long and narrow; snout short; -greatest width of skull at level of quadratojugal; often no suture between -hypoplastra and hyoplastra; callosities on epiplastron and preplastra usually -lacking. - -_Description._--Plastral length of smallest hatchling, 2.9 centimeters (UMMZ -95613), of largest male, 26.0 centimeters (AMNH 63642), of largest female, -34.0 centimeters (UMMZ 38123). - -Septal ridges present; over-all coloration of carapace and plastron, and soft -parts of body of hatchlings slate or blackish; carapace having blackish, circular -blotches, usually fused at margin, often with pale centers on buff background -forming coarse reticulum; pale, narrow rim of carapace not separated from -ground color by dark marginal line; pale rim, coincident with marginal ridge, -absent from anteriormost nuchal region; longitudinal rows of tubercles on -carapace resembling ridges; undersurface blackish, usually having posterior part -of carapace pale with irregular blackish marks; blackish soft parts of body -dorsally having large, pale markings, most consistent of which are postocular -mark that may contact orbit, postlabial mark that curves around angle of jaws, -inverted Y on top of snout, and one or two streaks on side of neck. - -Over-all coloration of adults grayish, paler than in hatchlings; carapace gray -sometimes having slightly darker, large, irregular markings; mottled and -blotched pattern on females not contrasting; sex of many large individuals not -distinguishable on basis of pattern on carapace; pale rim of carapace obscure or -absent; soft parts of body dorsally gray or brownish on large adults of both -sexes, sometimes having slightly paler, large markings; small adult males usually -having contrasting pattern on head; surface of carapace smooth (not "sandpaper") -on adult males; undersurface whitish, throat often grayish; well-defined -marginal ridge; anterior edge of carapace laterally to region of insertion -of forelimbs studded with low, flattened tubercles resembling hemispheres, never -conical; carapace usually having blunted tubercles, best developed anteriorly -and posteriorly on midline, but sometimes linearly arranged, resembling ridges, -especially at margins; anterolateral parts of plastron often extending farther -forward than corresponding parts of carapace. - -Range in length (in cm.) of plastron of ten largest specimens of each sex -(mean follows extremes), males, 17.0-26.0, 20.0; females 23.3-34.0, 27.9; -ontogenetic variation in PL/HW, mean PL/HW of specimens having plastral -lengths 6.5 centimeters or less, 3.52, and exceeding 6.5 centimeters, 4.87; -ontogenetic variation in CL/CW, mean CL/CW of specimens having plastral -lengths 8.0 centimeters or less, 1.18, and exceeding 8.0 centimeters, 1.30; mean -CL/PCW, 2.01; mean HW/SL, 1.44; mean CL/PL, 1.26. - -Jaws of some skulls that exceed 75 millimeters in basicranial length having -expanded alveolar surfaces; greatest width of skull usually at level of quadratojugal -(72%); ventral surface of supraoccipital spine narrow proximally, usually -having medial ridge; foramen magnum rhomboidal; opisthotic-exoccipital spur -absent (82%), sometimes indicated by ridge (16%); distal part of opisthotic wing -tapered, not visible in dorsal view; lateral condyle of articular surface of quadrate -larger than medial articular surface, not tapered posteriorly; maxillaries in contact -above premaxillaries; usually a combination of seven neurals, seven pairs -of pleurals, and contact of seventh pair of pleurals (56%), often eight pairs of -pleurals (31%); angle of epiplastron forming approximate right angle; often no -suture between hypoplastra and hyoplastra; callosities on preplastra and epiplastron -usually lacking. - -_Variation._--Crenshaw and Hopkins (1955:19) stated that in specimens from -Lake Okeechobee and southward the carapace is wider relative to the width of -the head, and Neill (1951:19) quoted Allen's observations that _ferox_ from southern -Florida "average larger and darker than those collected farther north." - -Carr (1952:417) reported that the pale reticulum on the carapace is yellowish -olive, the markings on head are yellow on an olive ground color, some -markings more orange, and the plastron slate gray. Duellman and Schwartz -(1958:271) mentioned that the carapace of hatchlings is edged in orange -grading to yellow posteriorly and has a pattern of bluish-black blotches on a -dull brown background, whereas the carapace is dull brown or blackish on -adults. Neill (_op. cit._:18) wrote "that the head stripes and the marginal -ring of the 'carapace' are orange rather than yellow (yellow at the time of -hatching, however)." - -The transition from the dark coloration of hatchlings to the paler coloration -of adults is gradual and subject to individual variation. The loss of -dark color ventrally occurs first on the plastral area, then the hind limbs, forelimbs, -posterior part of carapace and last on the neck and throat. The soft -parts of the body dorsally are gray or dark gray, and do not become so pale -as the ventral surface. The smallest specimen that I have seen displaying the -dark features of the hatchlings is a male, 7.7 centimeters (UMMZ 100673); -a female, 9.5 centimeters (UMMZ 110987), is the smallest specimen having -a whitish plastral area. The change from dark to pale coloration on the ventral -surface occurs at a size of 8.0 to 9.0 centimeters. The largest specimens I -have seen having indistinct, dusky blotches of the underside of the carapace -are a female, 11.3 centimeters (UMMZ 100836), and a male, 16.0 centimeters -(UMMZ 106322). A contrasting pattern on head and limbs, and a -dark throat are still evident in a female 19.2 centimeters (UMMZ 106302). - -_Comparisons._--_Trionyx ferox_ can be distinguished from all other species -of the genus in North America by the presence of a marginal ridge, longitudinal -ridges of tubercles on the carapace of juveniles (less evident in adults), -and the unique juvenal pattern and coloration. The lack of a juvenal pattern -and a smooth surface on the carapace (not gritty like sandpaper) distinguish -adult males from those of _T. spinifer_. Most adults of both sexes can be distinguished -from _spinifer_ and _muticus_ by the extension of the plastron farther -forward than the carapace (developed to a slight degree in some specimens -of _T. s. emoryi_). Both sexes of all ages can be distinguished from _muticus_ by -the presence of knoblike tubercles on the anterior edge of the carapace, and -septal ridges. - -_T. ferox_ is the largest species in North America; the maximum size of the -plastron in adult males is approximately 26.0 centimeters (16.0 in _spinifer_) -and of adult females, 34.0 centimeters (31.0 in _spinifer_). The head is wider -in _ferox_ than in _muticus_ and most subspecies of _spinifer_ (closely approached -by _asper_, _guadalupensis_, _emoryi_ and _T. ater_). The carapace is narrower in -_ferox_ than in _muticus_ and most subspecies of _spinifer_ (closely approached by -_emoryi_ and _T. ater_). The snout is shortest in _ferox_, but almost as short in -_T. s. emoryi_ and _T. ater_. _T. ferox_ has proportionately the longest plastron in -relation to length of carapace. - -Most skulls of _ferox_ differ from those of _muticus_ and _spinifer_ in having the -greatest width at the level of the quadratojugal (as do some _T. s. asper_; see -account of that subspecies). In the skull, _ferox_ resembles _spinifer_ but differs -from _muticus_ in having the 1) ventral surface of the supraoccipital spine narrow -proximally, and usually having a medial ridge, 2) foramen magnum rhomboidal, -3) distal part of opisthotic wing tapered, 4) lateral condyle of articular -surface of quadrate not tapered posteriorly, and larger than medial articular -surface, and 5) maxillaries in contact above premaxillaries. _T. ferox_ resembles -_muticus_ but differs from most individuals of _spinifer_ in lacking a well-developed -opisthotic-exoccipital spur. _T. ferox_ resembles _spinifer_ but differs from -_muticus_ in having the epiplastron bent at approximately a right angle; _ferox_ -differs from both _muticus_ and _spinifer_ in lacking a callosity on the epiplastron -and probably in the more frequent fusion of the hyoplastra and hypoplastra. - -_Remarks._--The early taxonomic history of _Trionyx ferox_ has been discussed -in detail by Stejneger (1944:27-32), who explained that Dr. Alexander -Garden of Charleston, South Carolina, sent a description and specimen of -_T. ferox_ to Thomas Pennant, and at the same time sent another specimen with -drawings to a friend, John Ellis, in London. Pennant presented one of the -specimens and drawings and the description to the Royal Society of London -in 1771; the description was published in 1772 and included Garden's drawings. -Because two specimens were involved the possibility exists that the -description (text, drawings and type specimen) is a composite based on two -specimens. - -I have not seen the type. Garden's original description (_in_ Pennant, 1772:268-271) -leaves little doubt that the text subject is a large adult female of _ferox_ -(see especially the statements, "fore part, [of carapace] just where it covers the -head and neck, is studded full of large knobs, [and] The under, or belly plate, -... is ... extended forward two or three inches more than the back -plate, ..."). I am indebted to Mr. J. C. Battersby, British Museum (Natural -History), Department of Zoology (Reptiles), for information concerning -the type and for comparing it with the text description and three figures published -by Pennant. The carapace of the type is approximately 16 inches long, -13-1/2 inches wide, and has low, flattened, knoblike tubercles along the anterior -edge. Some inaccuracies on the part of the artist (such as five claws on both -feet on the right side of Fig. 3, and four claws on the left front foot of Fig. 2 are -evident), and slight changes in the proportions of the type would have occurred -after death and preservation. It is the opinion of Mr. Battersby that the type, -text description and three figures represent one specimen. Figures 1 and 2, -dorsal and ventral views respectively, probably represent the same specimen -from life; the neck is withdrawn and the tail tip is visible in dorsal view, but -concealed beneath the posterior edge of the carapace in ventral view. Presumably -the same specimen (probably drawn from dried and stuffed animal) -is depicted in Figure 3 (dorsal view); the neck is fully extended and a large -part of the thick, pyramidal tail is visible in dorsal view. British Museum (Natural -History) 1947.3.6.17 is considered a holotype. The three figures published -by Pennant have been duplicated by Schoepff (1795:Pl. 19) and Duméril and -Bibron (1835:482). To my knowledge, the holotype was first specifically designated -as the "(Type.)" of _T. ferox_ by Boulenger (1889:259). The skull of the -holotype is figured by Stejneger (1944:Pl. 5). - -Garden did not list a specific locality for the two specimens that he sent to -London, but did mention that the turtle was common in the Savannah and -Altamaha rivers (of Georgia), and rivers in east Florida. Boulenger (_loc. cit._) -stated that the locality of the holotype was "Georgia." Baur (1893:220) restricted -the type locality to the "Savannah river, Ga." Neill (1951:17), who -believed _T. ferox_ to be absent from the Savannah River, changed the type -locality of _ferox_ to east Florida. Schwartz (1956:8) reappraised the status of -softshells in Georgia and Florida and reëstablished the Savannah River (at -Savannah), Georgia, as the type locality of _T. ferox_. - -Pennant failed to use binomial nomenclature when he published the type -description of Garden. The first name-combination (_Testudo ferox_) was proposed -by Schneider (1783:220). - -Lacépède (1788:137, Pl. 7) referred to Garden's description in Pennant -only as "The Molle" but on a folded paper chart entitled "Table Méthodique -des Quadrupèdes ovipares," which is inserted after an introduction of 17 pages, -listed _T. mollis_; this name is again listed on another folded chart, entitled -"Synopsis methodica Quadrupedum oviparorum," which is inserted between -pages 618 and 619 under the genus _Testudo_. The illustration (Pl. 7) was -taken from Pennant (Duméril and Bibron, _loc. cit._). The type locality has -been designated "(following Stejneger, 1944) as eastern Florida" by Schmidt -(1953:108). - -Bartram failed to use a binomial name with his description of "the great -soft shelled tortoise," which appeared in his _Travels_ (1791:177-179, Pl. 4 and -unnumbered plate between pages 282 and 283) and two editions of a French -translation (1799 and 1801, 1:307); see Harper (1940). Recently, Bartram's -_Travels_ has been placed on the Official Index of Rejected and Invalid Works -in Zoological Nomenclature, Opinion 447 (see Hemming, 1957). Bartram's -description of a soft-shelled turtle has provided the basis for the proposal of -at least three name-combinations. The first was _Testudo_ (_ferox?_) _verrucosa_ -proposed in 1795 by Schoepff; it appeared simultaneously in _The Historia -Testudinum_ and in a German translation, _Naturgeschichte der Schildkröten_ -(see Mittleman, 1944:245). Stejneger (1944:26) listed the type locality as -eastern Florida. Daudin (1801:74), also referring to Bartram's description -in his _Voyage_ (French translation), proposed the name _Testudo bartrami_; -Harper (_op. cit._:717) restricted the type locality of _T. bartrami_ from "Halfway -pond," east Florida, to southwestern Putnam County between Palatka -and Gainesville, Florida. Rafinesque (1832:64-65), relying on the authenticity -of the illustrations in Bartram's _Travels_ that depict a soft-shelled turtle -having five claws on each of the hind feet, tubercles on the sides of the head -and neck, and ten scales in the middle of the carapace (presumably inaccuracies -or a composite on the part of the artist), referred to Bartram's description as -a new genus, _Mesodeca bartrami_, a name which Boulenger (1889:245, footnote) -referred to as "mythical." Geoffroy (1809a:18-19) considered Bartram's -description the basis for the recognition of a second species of _Chelys_ (binomial -nomenclature not employed), and Duméril and Bibron (_loc. cit._) suggested -that the description was based partly on a "Chelyde Matamata." -The descriptive comments of Bartram are not clearly applicable to _Testudo -ferox_ Schneider; _Trionyx ferox_, however, is the only species of soft-shelled -turtle known to occur in the region of Bartram's observations (east Florida), -and the type locality was restricted to Putnam County, Florida, by Harper. -The name-combinations, _Testudo___ (_ferox?_) _verrucosa_ Schoepff, _Testudo bartrami_ -Daudin, and _Mesodeca bartrami_ Rafinesque are junior synonyms of _Testudo -ferox_ Schneider. - -Schweigger (1812:285) referred _ferox_ to the genus _Trionyx_ following the -description of that genus by Geoffroy in 1809. _Testudo ferox_ was listed as a -synonym by Geoffroy in the description of _Trionyx georgicus_ (1809a:17); -Duméril and Bibron (1835:432) mentioned that the specific characters of -_georgicus_ were taken from Pennant. The name _Trionyx georgianus_ presumably -appears for this taxon in Geoffroy's earlier-published synopsis (1809:367). -_T. georgicus_ was listed as occurring in rivers of Georgia and the Carolinas; -the type locality was restricted by Schmidt (_op. cit._:109) to the Savannah -River, Georgia. The two specific names _georgicus_ and _georgianus_ are regarded -as substitute names and junior synonyms of _T. ferox_. - -Geoffroy (1809a:14-15) also described _Trionyx carinatus_, a name-combination -that hitherto has been considered a synonym of _Trionyx ferox_. There -is no indication from the description that _carinatus_ is applicable to _ferox_. -Most comments pertain to a description of the bony carapace and plastron, -which Geoffroy depicts in Plate 4. It is a young specimen judging from the -small and isolated preneural; the seventh pair of pleurals is unusual in being -fused (no middorsal suture), and the neurals seem large in proportion to -the size of the pleurals. The anterior border of the carapace is described -as having tubercles. Geoffroy listed _Testudo membranacea_ and _Testudo -rostrata_ as synonyms of _carinatus_. Fitzinger (1835:127) listed _T. membranacea_, -_T. rostrata_ and _T. carinatus_ as synonyms of _Trionyx javanicus_ -(= _T. cartilagineus_), which was also described by Geoffroy (_op. cit._:15). -Duméril and Bibron (_op. cit._:478, 482) considered _carinatus_ to be the young -of _spinifer_ (_ferox_ as synonym). Gray (1844:48), however, referred _T. membranacea_ -and _T. rostrata_ to the synonymy of _T. javanicus_, but considered _T. -carinatus_ to be a synonym of _T. ferox_ (_op. cit._:50), an interpretation followed -by all subsequent authors. _Trionyx carinatus_ is questionably listed as a -synonym of _ferox_ by Stejneger (1944:27). Duméril and Bibron (_op. cit._:482) -wrote that the young type of _carinatus_ is in the museum at Paris. Dr. Jean -Guibé informs me in letter of September 24, 1959, that the type of Geoffroy's -_T. carinatus_ cannot be found in the Natural History Museum at Paris. For -the present, _T. carinatus_ is considered a _nomen dubium_. According to Stejneger -(1944:27), _Trionyx brongniarti_ Schweigger is a substitute name for -_T. carinatus_. - -I am unable to add anything to Stejneger's (_op. cit._:32) account of _Trionyx -harlani_; the mention of its occurrence in east Florida indicates that it is indistinguishable -from _Testudo ferox_ Schneider. - -_T. ferox_ was considered to be indistinguishable from Lesueur's _Trionyx -spiniferus_ (described in 1827), until Agassiz (1857:401) pointed out the -differences between the two species. However, Agassiz (_op. cit._:402, Pl. 6, Fig. -3) regarded juveniles of _T. spinifer asper_ as the young of _ferox_. Consequently, -the geographic range of _ferox_, as envisioned by Agassiz, extended from -Georgia and Florida west to Louisiana. Neill (1951:15) considered all -American forms conspecific. Crenshaw and Hopkins (1955) and Schwartz -(1956) demonstrated that _ferox_ is a distinct species. - -Fitzinger (1843:30) designated the species _ferox_ as the type species of -his genus _Platypeltis_ as follows: "Platypeltis. Fitz. Am[erica]. _Platypelt. -ferox_. Fitz. Typus." If populations of soft-shelled turtles that are referable -to _Testudo ferox_ Schneider are considered to comprise a distinct genus by -future workers, _Platypeltis_ Fitzinger, 1835, is available as a generic name with -_Testudo ferox_ Schneider, 1783, as the type species (by subsequent designation). - -_Trionyx ferox_ in the northern part of its range is sympatric with _T. spinifer -asper_. In the region of overlap, the two species are nearly always ecologically -isolated; _ferox_ inhabits lentic waters, whereas _T. s. asper_ is partial to lotic -waters (Crenshaw and Hopkins, _op. cit._:16). There is no evidence of intergradation -or hybridization. - -Many characters of _Trionyx ferox_ that are lacking in other North American -forms are shared with some Asiatic softshells, such as the large size, longitudinal -rows of tubercles that resemble ridges on the carapace, and the marginal -ridge. It is thought that, of the living softshells in North America, _ferox_ is -more closely allied to Old World forms of the genus than to _muticus_ or _spinifer_. - -Carr (1940:107) recorded _ferox_ from Okaloosa County, Florida, in the western -end of the panhandle, whereas Crenshaw and Hopkins (1955:16) list the -known westward extent of range as Leon and Wakulla counties. AMNH 6933 -from west of the Apalachicola drainage in Washington County, Florida, tends -to substantiate Carr's record, which is not included on the distribution map. - -_Specimens examined._--Total 144, as follows: FLORIDA: _Alachua_: UMMZ -64178, 100969; USNM 10545, 10704, "near" Gainesville; UMMZ 56599, Levy -Lake. _Brevard_: AMNH 12878, Canaveral. _Broward_: UMMZ 109441, Hugh -Taylor Birch State Park; USNM 109548, 22 mi. WNW, 6 mi. SSE Fort Lauderdale. -_Collier_: USNM 86828, Tamiami Trail, "near" Birdon. _Dade_: AMNH -50936, UMMZ 10183, 110981, Miami; USNM 84079, 86942, 15 mi. from (west) -Miami, Tamiami Trail; UMMZ 111371, 19 mi. W, 1.3 mi. S Miami; UI 28984, -35 mi. W. (Miami) Tamiami Trail; AMNH 69932-33, UMMZ 101582, 101584, -104024, 40-45 mi. W Miami, Tamiami Trail. _Glades_: UMMZ 100836, mouth of -Kissimmee River. _Hendry_: UMMZ 106302, 10.2 mi. SE Devil's Garden; -UMMZ 106303-04, 106321-22, 30 mi. S Clewiston, near Devil's Garden. -_Hernando_: TU 13624, 0.5 mi. S Citrus Co. line on US Hwy. 19. _Highland_: -AMNH 65537, 71618, Archbold Biol. Stat., Lake Placid; AMNH 65622, Hicoria. -_Hillsborough_: TU 13960, Hillsborough River, _ca._ 20 mi. NE Tampa; USNM -51184, Tampa; USNM 71156, Plant City. _Indian River_: USNM 55316, Vero -Beach; USNM 59318, Sebastian. _Lake_: UMMZ 36072, USNM 20189, 029210, -029339, 38123, Eustis; UMMZ 76754-56, Lake Griffin. _Lee_: UMMZ 102276, -14 mi. SE Punta Gorda. _Leon_: CNHM 33701, USNM 95767, Lake Iamonia; -USNM 103736, Silver Lake. _Marion_: AMNH 8294-95, UMMZ 95613 (4), -USNM 52476-83, 100902-04, Eureka; AMNH 63642, near Salt Springs. _Martin_: -TNHC 1292, 8.4 mi. N Port Mayaca. _Okeechobee_: AMNH 57379-84, Lake -Okeechobee; AMNH 5931-32, Kissimmee Prairie. _Orange_: USNM 51421, -56805, Orlando; KU 16528. _Osceola_: USNM 029448, 029450-64, 029467-68, -029470, 029474-75, Kissimmee. _Palm Beach_: UMMZ 54101, Palm Beach; -USNM 73199, Delray Beach. _Pinellas_: USNM 51417-20, St. Petersburg. _Polk_: -AMNH 25543, Lakeland; UMMZ 112380, 6.7 mi. S Lake Wales; USNM 60496, -60532, 60534, 61083-87, Auburndale. _Putnam_: USNM 4373, 7651, Palatka; -USNM 26035, ponds "near" Welaka. _Sarasota_: USNM 61352, Lake Myakka. -_Sumpter_: UMMZ 71791, Bushnell. _Volusia_: UMMZ 100673, Lake Helen. -_Washington_: AMNH 6933, Washington. _County unknown_: AMNH 4758; -USNM 8899, St. John's River: USNM 59727-28, Lake Okeechobee, "near" -mouth Taylor's Creek; USNM 84080. - -GEORGIA: _Baker_: SM 2083, USNM 029619, 38980-81, 70398, Mimsville. -_Berrien_: USNM 62217, Banks Mill Pond. _Charlton_: AMNH 69934, Okefinokee -Swamp, SW Billy's Island; UMMZ 90010, east edge Okefinokee Swamp; USNM -84603, Okefinokee Swamp, Chesser's Island. _Irwin_: USNM 56804. _Lowndes_: -UMMZ 67706, 10 mi. S Valdosta. _McIntosh_: USNM 19621, Darien. - -SOUTH CAROLINA: _Charleston_: USNM 9670, Charleston. - -NO DATA: AMNH 22750; USNM 71608-09. - -_Records in the literature._--FLORIDA: _Alachua_: 10 mi. ENE Gainesville -(Schwartz, 1956:18). _Brevard_: Merritt Island (Neill, 1958:6). _Broward_: -Fort Lauderdale (Schwartz, _op. cit._:19). _Charlotte_: (Carr, 1940:107). _Clay_: -Green Cove Springs (Brimley, 1910:18); St. John's River (Crenshaw and Hopkins, -1955:21); Doctor's Inlet (Schwartz, _op. cit._:18). _Collier_: Royal Palm -Hammock (Crenshaw and Hopkins, _op. cit._:20); 11.2 mi. E Monroe Station -(Schwartz, _op. cit._: 19). _Columbia_: (Carr, _loc. cit._). _Dade_: Paradise Key -(Schwartz, _loc. cit._); Homestead (eggs, Stejneger, 1944:43). _Duval_: 4-10 -mi. S Jacksonville (Deckert, 1918:31). _Glades_: _ca._ 8 mi. SW Okeechobee -State Park. _Lake_: Alexander Springs (Schwartz, _op. cit._:18). _Lee_: 18 mi. -S Fort Myers (Conant, 1930:63); 6 mi. SE Fort Myers (Hamilton, 1947:209). -_Levy_: Gulf Hammock (Schwartz, _loc. cit._); Brownson (Stejneger, _op. cit._:42). -_Monroe_ and _Okaloosa_ (Carr, _loc. cit._). _Okeechobee_: 6 mi. E Kissimmee River; -state hwy. 78 "near" Okeechobee-Glades co. line. _Palm Beach_: SW part of -Lake Okeechobee, near Clewiston; Milton Island Cove (Schwartz, _loc. cit._). -_Pasco_: mouth Pithlachascotee River (Neill, _op. cit._:26). _Pinellas_: Belleair -(Brimley, _loc. cit._); Seminole (Conant, _loc. cit._); 5 mi. E Clearwater (Schwartz, -_op. cit._:19); Gulf Port (Stejneger, _op. cit._:43). _Polk_: Lake Shipp, near -Winter Haven (Telford, 1952:185). _Sarasota_: 15 mi. E Sarasota (Conant, -_loc. cit._); Venice (Conant, _op. cit._:61). _Taylor_: "near" Foley. _Wakulla_: -"near" Crawfordville (Crenshaw and Hopkins, _op. cit._:15). - -GEORGIA: _Baker_: 5 mi. NW Newton, 5 mi. W Newton, 4 mi. N Newton. -_Ben Hill_: 6 mi. E Fitzgerald (Crenshaw and Hopkins, 1955:15). _Bulloch_: 14 -mi. SE Statesboro (Schwartz, 1956:19). _Decatur_: "near" Bainbridge (Crenshaw -and Hopkins, _loc. cit._). _Emanuel_: "near" Midville. _Evans_: 8 mi. NE -Manassas, Tattnall County. _Ware_: Laura Walker State Park (Schwartz, _loc. -cit._). _Wilcox_: 3 mi. SE Forest Glen (Crenshaw and Hopkins, _op. cit._:19). - -SOUTH CAROLINA: _Beaufort_: 7 mi. NE Gardens Corner (Schwartz, 1956:19). -_Chatham_: Savannah River at Savannah (Schwartz, _op. cit._:8-9). _Colleton_: 5 -mi. from Whitehall, Combahee River (Schwartz, _op. cit._:19). - - -=Trionyx spinifer= Lesueur - -Spiny Softshell - -_Range._--In Canada, southern Ontario and Quebec; in the United States, -northwestern Vermont and western New York south to northern Florida, east -to central Montana, eastern Wyoming and Colorado, and New Mexico; introduced -into the Colorado River system of California, Nevada, Arizona and New -Mexico; in México, the northern part of the states of Tamaulipas, Nuevo León, -Coahuila, and eastern Chihuahua (see map, Fig. 19). - -_Diagnosis._--Juvenal pattern uniform tan or brownish lacking markings, having -whitish dots or spots, or having well-defined, blackish ocelli or spots; surface -of carapace "sandpapery" in adult males; conical projections (in some subspecies) -along anterior edge of carapace in large females; contrasting pattern of -blackish marks on pale background (in some subspecies) on dorsal surface of -limbs of adult males. - -Opisthotic-exoccipital spur well-developed; epiplastral callosity, when present, -not covering entire surface. - -_Description._--Septal ridges present; external and proportional characteristics -variable (see accounts of subspecies); range in length of plastron (cm.) of ten -largest specimens of each sex (mean follows extremes), males, 13.8-16.0, 14.4; -females, 26.0-31.0, 28.0. - -[Illustration: FIG. 19. Geographic distribution of _Trionyx spinifer_. - -Guide to subspecies: - - 1. _T. s. spinifer_ - 2. _T. s. hartwegi_ - 3. _T. s. asper_ - 4. _T. s. pallidus_ - 5. _T. s. guadalupensis_ - 6. _T. s. emoryi_ -] - -Greatest width of skull usually at level of squamosal (74%); foramen -magnum rhomboidal; ventral surface of supraoccipital spine narrow -proximally, usually having medial ridge; opisthotic-exoccipital spur -well-developed (66%); distal part of opisthotic wing tapered, not -visible in dorsal view; lateral condyle of articular surface of -quadrate larger than medial articular surface, not tapered -posteriorly; maxillaries in contact above premaxillaries (88%); -usually a combination of seven neurals, seven pairs of pleurals and -contact of seventh pair of pleurals (83%); angle of epiplastron -approximately 90 degrees; callosities when present on epiplastron not -covering entire surface; hyo-hypoplastral suture usually present. - -_Comparisons._--_Trionyx spinifer_ can be distinguished from _T. -ferox_ and _T. muticus_ by the presence of any one of the characters -mentioned in the "Diagnosis." Both sexes and all sizes of _T. -spinifer_ resemble _ferox_ but differ from _muticus_ in having septal -ridges. Most individuals of _T. spinifer_ (except some large females) -resemble _muticus_ but differ from _ferox_ and large females of _ater_ -in having a pale outer rim that is separated from the ground color of -the carapace by a distinct (_spinifer_) or dusky (_muticus_) dark -line. Large females of the subspecies _spinifer_, _hartwegi_, _asper_ -and _pallidus_ may have enlarged conical projections along the -anterior edge of the carapace and, unless these projections are -considerably worn, are readily distinguished from large females of -_ferox_ (flattened, knoblike prominences), and _muticus_ and _ater_ -(smooth surface, no prominences). Large females of the subspecies -_guadalupensis_ and _emoryi_ resemble _muticus_ and _ater_, and to -some extent _ferox_, in having low, scarcely elevated prominences -along the anterior edge of the carapace. Some females of _emoryi_ -resemble _ferox_ in that the plastron extends farther forward than the -carapace. - -_T. spinifer_ is intermediate in size between _ferox_ (larger) and -_muticus_ (smaller); the maximum size of the plastron in adult males -is approximately 16.0 centimeters (14.0, _muticus_; 26.0, _ferox_), -and of females, 31.0 centimeters (21.5, _muticus_; 32.5, _ferox_). The -head for all subspecies of _spinifer_ is proportionately narrower than -in _ferox_ but wider than in _muticus_. - -In the skull, _spinifer_ more closely resembles _ferox_ than -_muticus_, but differs from both _ferox_ and _muticus_ in usually -having a well-developed opisthotic-exoccipital spur. Skulls of -_spinifer_ resemble those of _muticus_ but differ from those of -_ferox_ in being widest at the level of the squamosal. Skulls of -_spinifer_ resemble those of _ferox_ but differ from those of -_muticus_ in having the 1) ventral surface of the supraoccipital spine -narrow proximally, and usually having a medial ridge, 2) foramen -magnum rhomboidal, 3) distal part of opisthotic wing tapered, 4) -lateral condyle of articular surface of quadrate not tapered -posteriorly, and larger than medial articular surface, and 5) -maxillaries in contact above premaxillaries. _T. spinifer_ resembles -_ferox_ but differs from _muticus_ in having the epiplastron bent at -an approximate right angle. _T. spinifer_ differs from _ferox_ in -having an epiplastral callosity, and from _muticus_ in that the -callosity does not cover the entire surface of the epiplastron. The -hyo-hypoplastral suture is present more often in _spinifer_ and -_muticus_ than in _ferox_. - -_Remarks._--Gray (1869:221) proposed the generic name _Callinia_ as a -new name for _Aspidonectes_ as understood by Agassiz (1857:403). Gray -referred _Trionyx spiciferus_ (= _spiniferus_) Lesueur to _Callinia_. -Stejneger (1907:514) designated _Trionyx spiniferus_ Lesueur as the -type species of _Callinia_. If _Trionyx spiniferus_ Lesueur is -considered to be generically distinct from other soft-shelled turtles, -_Callinia_ Gray, 1869, is available as a generic name with _Trionyx -spiniferus_ Lesueur, 1827, as the type species by subsequent -designation. - -_Geographic variation._--_T. spinifer_ is the most variable and -widespread species of the genus in North America. Size of ocelli on the -carapace decreases from east to west on turtles inhabiting waterways of -the Upper Mississippi River drainage. The most impressive gradient, -geographically oriented from western Louisiana to southwestern Texas is -seen in each of several features: decrease in size of tubercles on the -anterior edge of the carapace, reduction in contrast of pattern on the -dorsal surface of limbs and side of head, change in pattern on the -dorsal surface of the snout, and increase in the size of white spots on -the carapace. But the gradient in size of white spots is reversed in _T. -s. emoryi_, which has small white spots on the carapace. Some of the -characters at the western terminus of this geographical gradient are -shared with _T. ater_ and _muticus_. Those subspecies comprising the -_emoryi_ group also show proportional characters that correspond closely -with those of _T. ferox_. - -On the basis of tuberculation and pattern on carapace, side of head, -dorsal surface of limbs and snout, _Trionyx spinifer_ may be divided -into six subspecies. - - -=Trionyx spinifer spinifer= Lesueur - -Eastern Spiny Softshell - -Plates 33, 34, and 52 - - _Trionyx spiniferus_ Lesueur, Mém. Mus. Hist. Nat. Paris, 15:258, - pl. 6, December, 1827. - - _T[rionyx] s[pinifer] spinifer_ Schwartz, Charleston Mus. Leaflet, - No. 26:11, May, 1956. - - _Trionyx ocellatus_ Lesueur, Mém. Mus. Hist. Nat. Paris, 15:261, - December, 1827. - - _Apalone hudsonica_ Rafinesque, Atlan. Jour., Friend Knowledge, - Philadelphia, 1(No. 2, Art. 12):64, Summer, 1832. - - _Trionyx annulifer_ Wied-Neuwied, Riese Nord-Amerika, 1(pt. 3):140, - 1838. - - _Tyrse argus_ Gray, Cat. Tort. Croc. Amphis. Brit. Mus., p. 48, - 1844. - - _Aspidonectes nuchalis_ Agassiz, Contr. Nat. Hist. United States, - 1(pt. 2):406, 1857. - - _?G[ymnopus] olivaceus_ Wied-Neuwied, Nova Acta Acad. - Leopold.-Carol., 32:55, pl. 5, 1865. - -_Type._--Lectotype, Museum d'Histoire Naturelle, Paris, No. 8808; -large stuffed female obtained by C. A. Lesueur from the Wabash River, -New Harmony, Posey County, Indiana (Pl. 52). - -_Range._--Northeastern United States and extreme southeastern Canada -in tributaries flowing into the Mississippi River from the east, and -the St. Lawrence River drainage; extreme southern Quebec and Ontario, -Canada, east through southern Great Lakes region to Wisconsin, and -south through New York, western Pennsylvania and Illinois to Tennessee -and western Virginia (see map, Fig. 19). - -_Diagnosis._--Juvenal pattern of large, thick-bordered black ocelli, -often 9-10 millimeters in diameter in center of carapace on adult -males, and 2-3 millimeters in diameter on hatchlings (mean OD/PL, -Michigan, .066); only one dark marginal line separating pale rim of -carapace from dorsal ground color. - -_Description._--Plastral length of smallest hatchling, 2.7 centimeters -(UMMZ 89950, INHS 3143); of largest male, 14.5 centimeters (UMMZ -72512); of largest female, 31.0 centimeters (UMMZ 40866). - -Carapace olive, having large ocelli in center but smaller ocelli or -spots at sides; ocelli often interrupted; pale rim of carapace not -four or five times wider posteriorly than laterally, separated from -darker ground color of carapace by one dark marginal line; large -females often having remnants of ocelli at sides of carapace on -mottled and blotched background; pattern on snout of pale, -dark-bordered stripes that unite forming acute angle in front of eyes; -well-defined dark markings in subocular and postlabial region; pattern -contrasting with ground color on side of head; postlabial stripe -interrupted, diffuse; pale postocular stripe having blackish borders -interrupted, not uniting with postlabial stripe; dorsal surface of -soft parts of body having contrasting pattern, largest blackish marks -on hind limbs; elongate tail of adult males having pale dorsolateral -bands with well-defined lower blackish borders; underparts whitish, -often having blackish marks, except in center of plastral area; dark -marks on webbing of limbs, palms and soles; dark streaks often -coincident with digits; small conical tubercles on anterior edge of -carapace on adult males; conical or equilateral tubercles on anterior -edge of carapace of large females; accessory knoblike tubercles in -nuchal region and in middle of carapace posteriorly on large females. - -Ontogenetic variation in PL/HW, mean PL/HW of specimens having -plastral lengths 7.0 centimeters or less, 4.09, and exceeding 7.0 -centimeters, 5.50; ontogenetic variation in CL/CW, mean CL/CW of -specimens having plastral lengths 8.5 centimeters or less, 1.12, and -exceeding 8.5 centimeters, 1.21; mean CL/PCW, 2.02; mean HW/SL, 1.30 -(including subspecies _hartwegi_); mean CL/PL, 1.39. - -_Variation._--Variant individuals include: UMMZ 72512, an adult male, -having some ocelli seven millimeters in diameter that are almost solid -spots; UMMZ 89659 having postocular and postlabial stripes connected -on right side of head; UMMZ 95615, 52948, 54402 having inner dark -borders of pale stripes on snout represented by short dashes and dots -(a ragged line connecting anterior margins of orbits on 54402); UMMZ -52948, 89659 having interrupted, black marginal lines on carapace with -ends of some segments oriented inward and overlapping portion of -adjacent segments; UMMZ 81699, female having plastral length of 19.0 -centimeters, lacking conspicuous tubercles on anterior edge of -carapace; UI 2403, CNHM 92204 having extensive dark mottling and -marbling on throat and neck, undersurface of limbs and posterior -portion of carapace. - -_Comparisons._--_T. s. spinifer_ can be distinguished from all other -subspecies of _T. spinifer_ by the presence of large black ocelli -(diameter 9-10 mm. on adult males, 2-3 mm. on hatchlings) in -combination with only one dark marginal line. _T. s. spinifer_ -resembles _asper_ in having ocelli or dots on the carapace but differs -from _asper_ in having only one dark marginal line and larger ocelli. -_T. s. spinifer_ differs from _hartwegi_ only in the large size of the -ocelli. _T. s. spinifer_ resembles _hartwegi_ and _asper_ but differs -from _pallidus_, _guadalupensis_ and _emoryi_ in having blackish spots -and ocelli on the carapace and lacking whitish dots. _T. s. spinifer_ -resembles _hartwegi_, _asper_, and _pallidus_ and differs from -_guadalupensis_ and _emoryi_ in having conical or knoblike tubercles -on the anterior edge of the carapace on large females. - -_T. s. spinifer_ differs from the subspecies _asper_, _guadalupensis_ -and _emoryi_ in having a relatively narrower head, and from _emoryi_ -in having a relatively wider carapace. _T. s. spinifer_ resembles -_hartwegi_ and _asper_ but differs from the other subspecies in having -the carapace widest at a plane approximately one-half way back on the -carapace. The subspecies _spinifer_ and _hartwegi_ have longer snouts -than _pallidus_, _guadalupensis_, and _emoryi_. _T. s. spinifer_ -differs from _asper_ but resembles all the other subspecies in having -a relatively longer plastron. - -_Remarks._--Lesueur's description of _Trionyx spiniferus_ -(1827:258-261, Pl. 6) seems to be based mostly, if not entirely, on a -large female (length of carapace, 13 inches), which was "Le plus grand -des individus observes ..." (_op. cit._:258); an accompanying -illustration depicting the dorsal surface of the bony carapace is -unusual in lacking neurals (Pl. 6, E). Duméril and Bibron (1835:481) -mentioned eight or nine additional specimens that Lesueur sent to the -Museum of Natural History in Paris. Dr. Jean Guibé informed me under -letter dated September 24, 1959, that a larger stuffed female, bearing -catalog number 8808 is regarded as the holotype, and that there are -seven additional specimens (1949, 4143, 8807, 8809-12) in the museum -at Paris. All turtles were obtained by Lesueur from the Wabash River. -To my knowledge no specimen that was available to Lesueur has been -specifically designated as a type. Because the description seems to be -based on one specimen, undoubtedly No. 8808, this specimen has been -regarded as the holotype. However, Lesueur referred to several -specimens and did not mention a type in the original description; -consequently I prefer to regard No. 8808 as a lectotype. - -Lesueur also described _Trionyx ocellatus_ (_op. cit._:261-263) as a -variety of _T. spiniferus_ having ocelli, or parts thereof, on the -carapace and mentioned three specimens. The total number of specimens -that were available to Lesueur is unknown. One young alcoholic -specimen having ocelli is in the British Museum (Natural History) -(Gray, 1855:69). The same letter from Dr. Guibé stated that a specimen -in the Museum of Natural History, Paris, No. 6957, having a carapace -17 centimeters in length, conforms to the characters of _ocellatus_ as -mentioned by Lesueur, and was obtained from the Wabash River by -Lesueur. Two of the specimens mentioned by Lesueur (_loc. cit._) are -stated to be females. No. 6957 is an adult male and clearly shows the -juvenal pattern; it is regarded as the lectotype of _T. ocellatus_ -Lesueur, a name-combination, which is a synonym, based on a secondary -sexual difference in pattern. - -Rafinesque (1832:64) described a soft-shelled turtle from "the River -Hudson between the falls of Hadley, Glen and Baker, and further up to -the source" as _Apalone hudsonica_. The most outstanding -characteristic was the presence of five claws on the digits of each -limb. Rafinesque's recording of this characteristic was perhaps -influenced by the illustration of a softshell in Bartram's _Travels_ -that showed each limb with five, clawed digits. Perhaps this was the -basis for Boulenger (1889:245, footnote) regarding _Apalone_ as -"mythical." The large, yellowish, black-bordered spots, one behind and -one in front of the eye presumably represent segments of the -postocular stripe and the stripe on the snout; Rafinesque described -the carapace as "entire ... the margin is yellowish unspotted, then -comes a circular black line ..." and having "many round spots -occulated and clouded by having a brown margin, with grey dots -within." Except for five claws, the description is applicable to a -softshell and referable to _T. s. spinifer_. To my knowledge, the only -other records of the occurrence of soft-shelled turtles in the Hudson -river drainage are those of Eights (_in_ Bishop, 1923:120, Mohawk -River at Cohoes), and DeKay (1842:7, Mohawk River and Hudson River -near Albany); presumably these records are the basis for the comments -of Holbrook (_in_ Bishop, _loc. cit._), and symbolized as an isolated -locality by Conant (1958:318, map 35). The type locality of _Apalone -hudsonica_ is herein restricted to the Hudson River, near Baker's -Falls, Saratoga County, New York. - -Gray (1844:48) proposed the name _Tyrse argus_ for a specimen reported -to have come from Sierra Leone, West Africa; later (1855:68), he -referred the species to the genus _Trionyx_. After comparison with a -specimen of _T. spiniferus_ Lesueur, Gray (1864:89) was "doubtful -whether there must not have been some confusion about the habitat of -the specimen [which formed the basis of the description of _Tyrse -argus_], and whether it is not more probably a North American -species." The same author (1869:222; 1870:109) listed _Tyrse argus_ as -a synonym of _Callinia spinifera_ (= _Trionyx spiniferus_ Lesueur). - -Agassiz (_op. cit._:406-07) described _Aspidonectes nuchalis_ on the -basis of three adults from the Cumberland River and a number of young -from the headwaters of the Tennessee River. Boulenger (1889:245, -footnote 2) suggested that the status of _A. nuchalis_ required -further investigation. The species was not generally recognized after -the turn of the century. Barbour and Loveridge (1929:226) listed MCZ -1908 (one of the juveniles) and 1623-25 as cotypes. Stejneger -(1944:52) showed that _nuchalis_ was not distinguishable from _T. s. -spinifer_, and (_op. cit._:49) listed MCZ 1623-25 as cotypes. Schmidt -(1953:110) restricted the type locality to the Cumberland River, near -Nashville, Tennessee. - -Agassiz (_loc. cit._) mentioned that _nuchalis_ "differs strikingly -from Asp. spinifer in the much more elongated form of the male, and in -the great development of the marginal spines and of the tubercles upon -the carapace, ... But the most prominent specific character consists -in the marked depressions on either side of the blunt median keel, and -also in the triangular dilation of that keel behind the front margin -of the carapace." These characters seem to be of no taxonomic worth. I -have seen three syntypes (MCZ 1623-25) that undoubtedly correspond to -the three adult specimens mentioned by Agassiz. All are females, -measuring 19.5, 22.0, and 19.0 centimeters, respectively, in plastral -length, and lack a contrasting mottled pattern on the carapace; the -juvenal pattern is obscured, except for blackish spots at the edge of -the carapace on MCZ 1625, and parts of an ocellus on MCZ 1624. The -dorsal surfaces of the limbs are boldly marked. MCZ 1623, showing the -diagnostic feature mentioned by Agassiz, is photographed by Stejneger -(_op. cit._:Pls. 14, 15), and may be regarded as the lectotype of -_Aspidonectes nuchalis_ Agassiz. MCZ 1908 is one of the young syntypes -mentioned by Agassiz, and is referable to _spinifer_. The juvenal -pattern consists of spots and ocelli; the plastron measures 3.1 -centimeters in length, and the carapace 4.2 centimeters. - -Wied-Neuwied (1865:55-57, Pl. 5) described the species _?G_[_ymnopus_] -_olivaceus_, but was uncertain whether his interpretation was based on -a species, a variety or a secondary sexual difference. Wied-Neuwied -mentioned that Lesueur had already named this soft-shelled turtle as -_Trionyx ocellatus_, and agreed with Lesueur that those turtles having -occulated spots on the carapace were distinguishable from _T. -spiniferus_ and _T. muticus_. But because Duméril and Bibron in their -_Erpétologie Général_ failed to recognize _T. ocellatus_, Wied-Neuwied -felt obliged to bring it to the attention of his American colleagues -and he renamed it. Wied-Neuwied also stated, in the context of a -synonym, "Beschreibung einer Reise in Nord-America Bd. I., pag. 140." -This comment presumably refers to his earlier description of _T. -annulifer_ (1838:140); seemingly Wied-Neuwied considered _T. -annulifer_ and _G. olivacea_ as conspecific, although there is no -mention of _annulifer_ in the text proper. Stejneger (_op. cit._:49) -designated the type locality of _T. annulifer_ as the Ohio River at -Pittsburgh, Pennsylvania, and of _Gymnopus olivacea_ as New Harmony, -Wabash River, Illinois (_lapsus_ for Indiana). - -_Trionyx spiniferus_ was questionably considered distinct from _T. -ferox_ by Lesueur who listed "Testudo ferox Gm. Tortue de Pennant?" -and "Trionyx georgicus Geoffr.?" as synonyms. Subsequently, most -authors considered _T. spiniferus_ synonymous with _T. ferox_ until -Agassiz (1857) pointed out differences between the two species. - -The average size of the ocelli on the carapace of the subspecies -_spinifer_ decreases westward toward the Mississippi River; ocelli of -different sizes occur on different individuals from the same state and -presumably from the same population. For example, INHS 2281, plastron -9.9 centimeters in length, from Effingham County, Illinois, has some -ocelli eight millimeters in diameter, whereas a larger male from the -same locality, UI 1322, plastron 11.6 centimeters in length, has the -largest ocelli only five millimeters in diameter. For convenience, all -softshells having locality data from states east of the Mississippi -River are referred to _spinifer_, recognizing that intergradation -occurs with _hartwegi_ over a broad area paralleling the Mississippi -River. The type locality of _spinifer_ is in an area where most -turtles do not have the larger ocelli (diameter of seven to ten mm. on -adult males); however, some individuals from the Wabash River (UMMZ -63523, adult male, plastron 11.5 cm. in length, ocelli diameter seven -mm.) agree with more "typical" _spinifer_ to the east. Intergradation -with _asper_ possibly occurs in that part of the Tennessee River in -eastern Tennessee as exemplified by UMMZ 59198. - -Published reports indicate that _T. s. spinifer_ is not abundant in -some of the northeasterly parts of its geographic range. Adams and -Clark (1958:10) wrote that few softshells at Long Point on the -Canadian side of Lake Erie are "ever collected and the area's game -keepers report ... (none) ... seen in recent years. They also tell of -recurrent severe stormy winters in which the muddy bottom of the -marshland was repeatedly churned up and frozen. Such climatic -conditions could easily destroy a large part of the _Trionyx_ -population overwintering in the mud bottom." Wright (1919:8) reported -that softshells are "rarely seen" in bays on the New York side of Lake -Ontario, and Babcock (1938:53) wrote that _spinifer_ "is not common in -Lake Champlain." - -_T. s. spinifer_ probably extended its geographic range into the -Hudson River drainage of New York _via_ the Erie Canal (connected -Buffalo and Albany) after its completion in the early 1800's (DeKay, -1842:7). Now, the New York Barge Canal (essentially the Erie Canal, -but with minor changes in course and the addition of several spurs) -provides an avenue for dispersal of _spinifer_ to the Hudson River -drainage, Lake Ontario and intervening waterways in New York (Mertens, -1928:199). Netting (1944:86-87), however, suggested that _spinifer_ -occupied Lake Champlain, the Finger Lakes, Mohawk River and upper -Hudson in the late stages of the formation of the Great Lakes. - -A publication not seen by me is that of Mansueti and Wallace (1960). -Its title suggests that _Trionyx_ occurs in Maryland. - -The unsuccessful introduction of _T. s. spinifer_ in the Delaware -drainage in New Jersey has been discussed by Fowler (1907:213), who -wrote that they were found as early as the late 1860's and were -introduced when young presumably to stock aquaria. Records of -occurrence include Cooper's Creek, Camden County (Stone, 1906:168); -Woodbury, Gloucester County (Cope, 1894:889); and Paulins Kill at -Hainesburg, Warren County (Johnson, 1894:889). - -Surface (1908:122) believed that soft-shelled turtles "have doubtless -been introduced into the eastern part of Pennsylvania through the -canal from the Western and Central part of New York," and Roddy (_in_ -Neill, 1951:21) suggested that the species may be found in the -Susquehanna River. Babcock (1919:420) mentioned a young specimen of -_spinifer_ in the collection of the Boston Society of Natural History -that was obtained "in White River, Vermont," a tributary of the -Connecticut River of the Atlantic Coast drainage; seemingly this -record has not been accepted and the species is not established. To my -knowledge, populations of _T. s. spinifer_ do not occur in rivers of -the Atlantic Coast drainage, except probably the Hudson-Mohawk -drainage. - -Stockwell (1878:401) wrote that _spinifer_ was found "as high as -Athabasca." Presumably Stockwell referred to Lake Athabaska in -northern Alberta and Saskatchewan, Canada, a region where soft-shelled -turtles are unknown; see also the comments by Stejneger (1944:52). - -_Specimens examined._--Total 250 as follows: ALABAMA: _Morgan_: UMMZ -99578, "near" Decatur. - -ILLINOIS: _Adams_: INHS 2150, Quincy. _Bond_: INHS 8345, Greenville. -_Carroll_: CNHM 42116, Ordnance School Proving Ground. _Cass_: INHS -2151, Beardstown. _Champaign_: INHS 2273, 2311, 2413, 3142, "near" -Seymour; INHS 4229, Champaign; INHS 6163, Sidney. _Christian_: INHS -1560, Pana. _Coles_: INHS 1968-69, 2 mi. W Charleston. _Cumberland_: -INHS 2282, Greenup. _De Witt_: INHS 7674, Farmer City. _Effingham_: UI -1322, 2281, 19365, "near" Effingham. _Fulton_: INHS 5531, 2 mi. NE -Bluff City, Schyler County; UI 23449, Liverpool; UI 24611, Spoon -River, 18 mi. NW Canton. _Hancock_: USNM 53522, 59277, "near" -Hamilton. _Iroquois_: INHS 6869-70, 2.5 mi. N Crescent City. -_Jackson_: TU 1369 (12), Elkville. _Kane_: CNHM 42400, Aurora. -_Kankakee_: CNHM 324, Momence. _Kendall_: UI 2411, Plano. _Logan_: -INHS 7171-72, 6 mi. N Lincoln. _Madison_: USNM 60571. _Macoupin_: UI -2401-02, Beaver Dam Lake. _Mason_: CNHM 346, 470, INHS 1122, 1559, -5756-58, UI 42, 2404, Havana, Lake Chautauqua. _Mercer_: CNHM 3220, -New Boston. _Morgan_: CNHM 2067 (2), 3290, 3303-04, 3306, INHS 2152, -2154, 5132-37, USNM 54747, Meredosia. _Moultrie_: INHS 8989, 2 mi. NW -Lovington. _Peoria_: UI 2406-10, Peoria. _Pope_: INHS 5505, Lake -Glendale. _Putnam_: UMMZ 81604-14, 5 mi. N Henry, Marshall County. -_Schuyler_: UI 2405, "near" Ripley, Brown County. _Scott_: INHS 2149, -2153, Naples. _Union_: CNHM 18623, 6 mi. SW Jonesboro. _Vermilion_: -INHS 3142, Muncie; INHS (1 untagged); UI 1970, 3209, Danville; UI -2403, 1.5 mi. E Oakwood; UI 16265, Kickapoo State Park. _Wabash_: USNM -12061, Mt. Carmel. _Winnebago_: INHS 7185, Kishwaukee Forest Preserve; -INHS 7294, 1/2 mi. S Shirland. _County unknown_: USNM 7661. - -INDIANA: _Bartholomew_: UMMZ 61060, 10 mi. W Columbus. _Carroll_: USNM -42905-06, Burlington. _Clark_: UMMZ 110599, 14-mile Creek, 3 mi. NW -Charleston. _Decatur_: UMMZ 55416, 3 mi. S Westport. _Elkhart_: UMMZ -105598, Elkhart River, south of Goshen. _Gibson_: UMMZ 89744, Foot's -Pond. _Johnson_: UMMZ 108062, 2 mi. S Trafalgar. _Knox_: USNM 22711, -Vincennes. _Kosciusko_: AMNH 8379, UMMZ 84287 (5), Winona Lake; UMMZ -110235, Wawasee Lake. _Lake_: CNHM 11019, 11021-24, Crown Point. -_Marion_: UMMZ 103393, Ravenswood; UMMZ 110236, 1 mi. N Lawrence. -_Marshall_: CNHM 39299; USNM 33495, Yellow River north of Burr Oak; -USNM 33496-501, 35404, 42583-84, Lake Maxinkuckee. _Wells_: UMMZ -63523, Wabash River, Bluffton. _County unknown_ (Lagrange or -Marshall): USNM 50670, Twin Lakes. - -KENTUCKY: _Casey_: UMMZ 112252, trib. of Green River, south of -Yosemite. _Green_: UMMZ 116718, Little Barren River, 1.5 mi. E Monroe, -Hart County. _Rockcastle_: UMMZ 98767, Rockcastle River, 5 mi. above -Livingston. - -MICHIGAN: _Allegan_: UMMZ 42112, Kalamazoo River. _Barry_: UMMZ 53874, -Thornapple River, 3 mi. NW Hastings. _Bay_: UMMZ 74670. _Branch_: UMMZ -95615, 1 mi. S Kinderhook; UMMZ 70748, Hog Creek. _Calhoun_: UMMZ -89950 (3); UMMZ 79133, near Battle Creek. _Cass_: UMMZ 40866-67, -53005, Diamond Lake; UMMZ 40868, 52948, Long Lake. _Jackson_: UMMZ -72494. _Kalamazoo_: UMMZ 42130, 80534, Kalamazoo; UMMZ 90506, Gull -Lake; UMMZ 92599, Kellogg Bird Sanctuary. _Lenawee_: UMMZ 72457, -Devil's Lake; UMMZ 74662, Wolf Lake Park. _Livingston_: UMMZ 54401, -76190, Portage Lake. _Monroe_: UMMZ 44604-06, USNM 51213, "near" -Monroe. _Newaygo_: UMMZ 63469. _Oakland_: UMMZ 64363, Hay's Creek; -UMMZ 96539, Clinton River. _Ottawa_: UMMZ 81699. _St. Joseph_: UMMZ -38876, 38889, "near" White Pigeon; UMMZ 96537, Corey Lake. _Van -Buren_: UMMZ 90003, Wolf River, west of Kalamazoo, Kalamazoo County. -_Washtenaw_: SM 2035, 2038, 2105, UMMZ 39847, 96538, "near" Ann Arbor; -UMMZ 35765, 35769, 74518 (2), Portage Lake; UMMZ 54402-03, Little -Lake; UMMZ 89659, Huron River, Dexter; UMMZ 110583-85. _County -unknown_ (Washtenaw or Livingston): UMMZ 54400, Huron River near -Portage Lake. - -MISSISSIPPI: _Adams_: MCZ 46615, UMMZ 76446, "near" Natchez; MCZ -46621, 46633, USNM 01084, 01086, Washington. _Coahoma_: AMNH 5289, -5285-86, Moon Lake. _Lafayette_: MCZ 37173, Oxford; USNM 7650, -Abbeville? (reported from Abbeville, South Carolina by Pickens, -1927:113; see discussion by Stejneger, 1944:50, and my comments on -page 509 beyond). _LeFlore_: USNM 73668-69, Greenwood. _Madison_: USNM -95192, Big Black River. _Washington_: USNM 115980, Deer Creek. -_Yazoo_: UMMZ 86669, Panther Creek west of Yazoo City; UMMZ 83304, -Yazoo City. - -NEW YORK: _Monroe_: CNHM 92001-02, Genesee River, Rochester. _Wayne_: -AMNH 69931, CNHM 92004, Sodus Bay. - -OHIO: _Athens_: UMMZ 111793, east branch Shade Creek. _Franklin_: USNM -26290. _Lucas_: USNM 51214, Toledo. _Pike_: UMMZ 99309, Morgan's Fork, -Sunfish Creek. _Warren_: AMNH 4763, Little Miami River, 3 mi. below -Morrow. _County unknown_: USNM 21128-29, Cuyahoga River. - -TENNESSEE: _Benton_: UMMZ 113036, Eagle Creek, 1/2 mi. E Holliday. -_Bradley_: UMMZ 59197, west branch of Chestnee Creek, 7 mi. E -Cleveland. _Claiborne_: USNM 86677, 5 mi. SE Cumberland Gap, Powell -River. _Davidson_: MCZ 1623-25, Cumberland River near Nashville -(restricted locality); USNM 7165-67, Nashville. _Decatur_: KU 3000, -Perryville. _Hamilton_: USNM 131861, Chattanooga. _Monroe_: TU 16058, -Little Tennessee River, 10 mi. N Madisonville. _Obion_: UMMZ 53199, -USNM 102911, Reelfoot Lake. _Overton_: UMMZ 69561 (2), Wirmingham. -_Sevier_: TU 16132, UMMZ 86735, USNM 86681-82, near Sevierville; UMMZ -86734, Walden Creek "near" Gatlinburg. _County unknown_: MCZ 1908, -headwaters of Tennessee River. - -VIRGINIA: _Smythe_: USNM 101386, Holston River, Seven Mile Ford. - -WEST VIRGINIA: _McDowell_: USNM 33767, Dry Fork, Perryville (county -questionable, perhaps Randolph County). - -WISCONSIN: _Chippewa_: CNHM 8223, Lake Wissota, mouth of Yellow River, -Anson Twp. _Polk_: UMMZ 72511-12, St. Croix River "near" Never's Dam. -_County unknown_: CNHM 15971, Eau Claire River. - -_Records in the literature._--ONTARIO: _Carleton_: Ottawa -(questionable record). _Essex_: Point Pelee. _Haldimand_: Dunville. -_Kent_: Lake St. Clair. _Norfolk_: Long Point. _Oxford_: Beachville. -_Wentworth_: Hamilton Bay (Logier and Toner, 1955:51). - -QUEBEC: _Iberville_: Richelieu River at Iberville (Logier and Toner, -1955:51). - -ALABAMA: _Lawrence_: Courtland (Stejneger, 1944:53). - -ILLINOIS: _Boone_: Belvidere. _Bureau_: Bureau. _Cass_: Chandlerville. -_Clay_: Louisville (Cahn, 1937:189). _Cook_: Lake Michigan (Kennicott -_in_ Stejneger, 1944:44); Evanston (Necker, 1939:10); Chicago (Schmidt -and Necker, 1935:76). _Crawford_: Robinson. _Douglas_: northern part -of county (P. W. Smith, 1947:39). _Fayette_: Vandalia. _Fulton_: -Ellisville (Cahn, _loc. cit._). _Grundy_: Morris (Stille and Edgren, -1948:201). _Jackson_: Jacob (Cagle, 1942:158). _Jersey_: Grafton -(Cahn, _loc. cit._). _Kane_: Batavia; Dundee Game Farm (Stille and -Edgren, _loc. cit._). _Kankakee_: Kankakee River near Altort (Necker, -_loc. cit._). _Lake_: Fox Lake. _LaSalle_: Streator (Cahn, _loc. -cit._). _Lawrence_: (Hahn _in_ Stejneger, 1944:44). _Lee_: symbol on -map (Cahn, _loc. cit._). _McHenry_: McHenry (Stille and Edgren, _loc. -cit._). _Macon_: Decatur. _Macoupin_: Carlinville (Cahn, _loc. cit._). -_Ogle_: Oregon (Garman _in_ Cahn, _loc. cit._). _Randolph_: Chester, -Reily Lake. _Rock Island_: Barstow, Hillsdale, Rock Island (Cahn, -_loc. cit._). _Saline_: Horseshoe Lake (Stein, 1954:312). -_Stephenson_: Freeport (Cahn, _loc. cit._). _Union_: Bluff Lake -(Garman _in_ Cahn, _loc. cit._). _Whiteside_: Sterling, symbol on map -(Cahn, _loc. cit._). _Williamson_: Marion (Cagle, 1942:158). -_Winnebago_: Rockton; symbol in western part of county (Cahn, _loc. -cit._). _County unknown_: Fox River (Yarrow, 1882:29). - -INDIANA: _Brown_: 1 mi. below Helmsburg (Myers, 1927:339). _Clay_: Eel -River (Kirsch _in_ Stejneger, 1944:45). _Franklin_: (Hughes _in_ -Stejneger, _loc. cit._). _Jasper_: Jasper-Pulaski Game Preserve -(Swanson, 1939:690). _Jefferson_: Madison (Myers, _loc. cit._). -_Marion_: Irvington (Stejneger, _op. cit._:55). _Marshall_: 2 mi. NW -Culver (KKA). _Monroe_: Bloomington (McLain _in_ Stejneger, _op. -cit._:45). _Newton_: Lake Village (Stille and Edgren, _loc. cit._). -_Posey_: Wabash River at New Harmony (Lesueur, 1827:257). _Starke_: -Grant (Stille and Edgren, _loc. cit._). _Steuben_: Fish Creek "near" -Hamilton (Stejneger, _op. cit._:53). _County unknown_ (Knox or -Starke): USNM 72387, Knox (Stejneger, _op. cit._:55); "White Water -valley," east-central part of state (Butler, 1894:224). USNM 8359 (= -_Trionyx spinifer asper_) has been erroneously recorded from Madison, -Indiana, by Yarrow (1882:29) and Hay (1892:145); see discussion by -Cahn (1937:200) and Stejneger, (_op. cit._:73, 75). - -KENTUCKY: _Edmonson_: Green River, Mammoth Cave National Park -(Hibbard, 1936:281). _Fleming_: Fox Creek (Welter and Carr, 1939:130). -_Jefferson_: (Funkhouser, 1925:71). _Morgan_: (Stejneger, 1944:54). -_County unknown_: Ohio and Pond rivers (Funkhouser, _loc. cit._). - -MICHIGAN: _Berrien_: mouth of St. Joseph River at St. Joseph (Lagler, -1943:303). _Eaton_: Brookfield; Olivet (Clark _in_ Ruthven, Thompson -and Thompson, 1912:133). _Genesee_: (Miles _in_ Ruthven, Thompson and -Thompson, _loc. cit._). _Iosco_: (Lagler, 1943:283, symbol on map). -_Kent_: (Lagler, _loc. cit._). _Montcalm_: (Clark _in_ Ruthven, -Thompson and Thompson, _loc. cit._). _Muskegon_: Muskegon River "near" -Muskegon (Lagler, _op. cit._:303). _Van Buren_: Reynolds Lake, 2.5 mi. -E Lawrence (Edgren, 1942:180). - -MISSISSIPPI: _De Soto_: Lake Cormorant (Stejneger, 1944:55). _Holmes_: -Thornton (Cook, 1946:185). _Humphreys_: Belzoni (Stejneger, _loc. -cit._). _Sunflower_: _Warren_: Vicksburg, Eagle Lake (Cook, _loc. -cit._). _Washington_: Lake Washington (Smith and List, 1955:125); -Greenville (Stejneger, _loc. cit._). - -NEW YORK: _Albany_: Hudson River at Albany (DeKay, 1842:7); Mohawk -River at Cohoes (Eights _in_ Bishop, 1923:120). _Cattaraugus_: -Allegheny River and Red House Lake in Allegheny State Park (Eaton, -1945:115). _Chautauqua_: Lake Chautauqua (DeKay, _loc. cit._). -_Monroe_: Braddocks Bay and Long Pond on Lake Ontario (Wright, -1919:8). _Saratoga_: Hudson River near Baker's Falls (restricted -locality, Rafinesque, 1832:64). _County unknown_: Lake Cayuga; Mohawk -River (DeKay, _loc. cit._). - -OHIO (Conant, 1951:158-59, 264, except records from Allen, Geauga and -Noble counties): _Allen_: Sugar Creek, 6 mi. N Lima (Adler and Dennis, -1960:27). _Ashland_: Long Lake, Lake Twp.; Black Fork, Sec. 27, Green -Twp. _Athens_: Hocking River "near" Athens; "near" Fisher, Alexander -Twp. _Auglaize_: Pusheta Creek, west of Wapakoneta. _Brown_: White Oak -Creek, 1 mi. N Higginsport. _Butler_: Oxford. _Champaign_: Mad River, -4 mi. SW Urbana. _Coshocton_: Walhouding River, below dam. _Defiance_: -Auglaize River, Shawnee Scout Camp, Defiance Twp. _Erie_: Huron; -Sandusky. _Fairfield_: Buckeye Lake. _Franklin_: Alum Creek, -Westerville; Columbus. _Geauga_: Chardon Twp. (Wood, 1959:8). -_Greene_: Huffman Dam. _Hamilton_: Harrison; mouth of Miami River. -_Hardin_: "near" Hepburn. _Henry_: Maumee River, east of Napoleon; -Maumee River "near" Texas; Maumee River, 3 mi. W Texas. _Highland_: -Little Brush Creek, 2 mi. N Sinking Spring. _Huron_: Huron River -"near" Monroeville. _Jackson_: Canter's Cove, Jackson Twp.; Jackson -Lake. _Knox_: Brinkhaven. _Lake_: east branch Chagrin River, Kirtland; -Grand River, 4 mi. E Painesville. _Lawrence_: Pine Creek, Elizabeth -Twp. _Logan_: Miami River, "near" Indian Lake. _Lorain_: Oberlin. -_Lucas_: Lake Erie at Reno Beach, Jerusalem Twp.; Lake Erie, 1/2 mi. -offshore from mouth of Crane Creek; Maumee River at Maumee; Swan -Creek, W of Toledo; "near" Waterville; Swan Creek "near" Whitehorse. -_Madison_: London. _Medina_: Hinckley Lake. _Meigs_: Shade River, -below Darwin. _Miami_: Miami River, above Troy. _Monroe_: Cranenest -Fork, Green Twp. _Montgomery_: Mad River, Dayton; Miami River, Dayton; -Stillwater River, Dayton. _Morrow_: Kokosing River, Franklin Twp. -_Noble_: Jct. Sharon Twp. 1 and St. Rt. 78. (Adler and Dennis, -1960:27). _Ottawa_: East Harbour, Catawba Island. _Pike_: Chenoweth -Fork, Sunfish Twp.; Scioto River, Camp Creek Twp. _Ross_: Paint Creek -near Bainbridge. _Vinton_: Lake Hope; Lake Alma. _Warren_: Fort -Ancient. _Washington_: Dam No. 2, Muskingum River, "near" Marietta. -_Williams_: 1 mi. S Blakesley; St. Joseph River "near" Blakesley; West -Branch, St. Joseph River, Sec. 8, Bridgewater Twp.; Edgerton. _Wood_: -Grand Rapids; Grassy Creek, Rossford; Haskins; Maumee River opposite -Toledo. - -PENNSYLVANIA: _Allegheny_: Monongahela River above McKeesport -(Atkinson, 1901:154); Ohio River at Pittsburgh (Wied-Neuwied _in_ -Stejneger, 1944:44, 49). _Armstrong_: (Swanson, 1952:165). _Clarion_: -Clarion River "near" Clarion (Allen, 1955:228); Foxburg (= Foxbury?, -Boulenger, 1889:260). _Crawford_: _Elk_: _Erie_: Edinboro Lake. -_Forest_: (Swanson, _loc. cit._). _Indiana_: Plum Creek; Crooked Creek -(Netting _in_ Stejneger, 1944:48). _McKean_: (Swanson, _loc. cit._). -_Somerset_: Stoyestown (Surface, 1908:122). _Warren_: _Venango_: -Allegheny River south of Franklin (Swanson, _loc. cit._). - -TENNESSEE: _Chester_: South Fork, Forked Deer River just E Henderson -(Endsley, 1954:40). _Clay_: Mill Creek, 3 mi. from Butler's Landing; -Obey River above mouth of Wolf River at Lilydale; mouth of Wolf River -(Shoup, Peyton and Gentry, 1941:75); Iron Creek "near" Willow Grove -(Stejneger, 1944:56). _Fentress_: _Jackson_: (Gentry, 1941:332). -_Lake_: Reelfoot Lake (Parker, 1948:29). _Obion_: Walnut Log (Parker, -1937:85); east shore of Reelfoot Lake, Samburg (Rhoads, 1895:386). -_Overton_: Medlock Branch, tributary of West Fork Obey River north of -Allred (Shoup, Peyton and Gentry, _loc. cit._). _Roane_: 2 mi. S -Kingston (Stejneger, 1944:55). - -VERMONT: _Chittenden_: Lake Champlain, mouth of Winooski River; "near" -Burlington; Milton (= Minton) (Babcock, 1919:420). _Franklin_: Swanton -(Stejneger, 1944:55). - -WEST VIRGINIA: _Randolph_: Tygart River at Elkins (Green, 1937:116). - -WISCONSIN: _Burnett_: _Crawford_: (Pope and Dickinson, 1928:83). -_Dane_: Lake Wingra, Madison (Noland, 1951:54). _Grant_: (Pope and -Dickinson, _loc. cit._). _Green Lake_: Berlin (AMNH 6840-41, listed in -card file March 2, 1959). _Jefferson_: Lake Mills (Dickinson, -1950:75). _La Crosse_: West Salem (Pope, 1930:281). _Oneida_: _Pepin_: -(Pope and Dickinson, _loc. cit._). _Racine_: Eagle Lake (Edgren, -1944:498); Burlington; Rochester (Stille and Edgren, 1948:201). -_Sheboygan_: Sheboygan (KKA). _Trempealeau_: _Vernon_: "near" Viroqua -(Pope, _loc. cit._). _Walworth_: Lake Beulah (Dickinson, _loc. cit._). -_Washburn_: (Pope and Dickinson, _loc. cit._). _Waukesha_: Lac La -Belle (Cahn, 1929:8). _Winnebago_: Wolfe River (Dickinson, _loc. -cit._). - - -=Trionyx spinifer hartwegi= (Conant and Goin) - -Western Spiny Softshell - -Plates 35 and 36 - - _Amyda spinifera hartwegi_ Conant and Goin, Occas. Papers Mus. - Zool. Univ. Mich., No. 510:1, pl. 1, map 1, June 15, 1948. - - _T[rionyx] s[pinifer] hartwegi_ Schwartz, Charleston Mus. Leaflet, - No. 26:11, May, 1956. - -_Type._--Holotype, UMMZ 95365; alcoholic adult male; obtained at -Wichita, Sedgwick County, Kansas, in May, 1945, by Robert Young. - -_Range._--Central United States in tributaries flowing into the -Mississippi River from the west, except the Red River drainage; -eastern Montana, North Dakota, and southern Minnesota south to eastern -Colorado, northern Oklahoma and Arkansas (see map, Fig. 19). - -_Diagnosis._--Juvenal pattern of small ocelli, rarely as large as two -millimeters in diameter, or usually solid black dots that are not -much larger in center of carapace than at sides (mean OD/PL, Kansas, -.022); only one dark marginal line separating pale rim of carapace -from dorsal ground color. - -_Description._--Plastral length of smallest hatchling, 2.8 centimeters -(USNM 9928); of largest male, 13.1 centimeters (USNM 55687); of -largest female, 25.5 centimeters (KU 2283). - -Carapace olive, having small ocelli or black spots that are not much -larger in the center of the carapace than at the sides; pale rim of -carapace separated from darker ground color by one dark marginal line -and not four or five times wider posteriorly than laterally; large -females often having black dots at sides of carapace on mottled and -blotched pattern; pattern on snout of pale, dark-bordered stripes that -unite forming acute angle in front of eyes; well-defined dark markings -in subocular and postlabial region; pattern contrasting with ground -color on side of head; postlabial stripe broken, interrupted; pale -postocular stripe having blackish borders interrupted, not joining -with postlabial stripes; dorsal surface of soft parts of body having -contrasting pattern, largest blackish marks on hind limbs; elongate -tail of males having pale dorsolateral bands with well-defined, lower, -blackish borders; patterns on soft parts of body usually obscured or -absent on large females; underparts whitish, often having blackish -marks, except in center of plastral area; dark marks on webbing of -limbs, palms and soles; dark streaks often coincident with digits; -tubercles along anterior edge of carapace small and conical on adult -males, and conical or knoblike on large females; accessory, knoblike -tubercles in nuchal region and in middle of carapace posteriorly on -large females. - -Ontogenetic variation in PL/HW, mean PL/HW of specimens having -plastral lengths 7.0 centimeters or less, 4.24, and exceeding 7.0 -centimeters, 5.33; ontogenetic variation in CL/CW, mean CL/CW of -specimens having plastral lengths 8.5 centimeters or less, 1.12, and -exceeding 8.5 centimeters, 1.19; mean CL/PCW, 2.00; mean SL/HW, 1.30 -(including subspecies _spinifer_); mean CL/PL, 1.38. - -_Variation._--Variants include: CNHM 8949, UMMZ 72511 and TU 14591 -having ocelli approximately 4 millimeters in diameter that are almost -solid spots; KU 17728 having pale stripes on snout that lack black, -inner borders; TTC 719 (female, plastral length 20.7 cm.), having -distinct pattern on snout; USNM 14535, 17823, 55684, and 123446 (from -different localities) having markings confined to margins of carapace -(Stejneger, 1944:66, suggested that USNM 17823 probably came from -Texas); UMMZ 92667 (female, plastral length 6.7 cm.) lacking pattern -on carapace. - -_Comparisons._--_T. s. hartwegi_ can be distinguished from all other -subspecies of _T. spinifer_ by the presence of small dots and ocelli -on the carapace that are all of approximately the same size in -combination with only one dark marginal line. _T. s. hartwegi_ -resembles _asper_ in having small blackish ocelli or dots on the -carapace but differs from _asper_ in having only one dark marginal -line. _T. s. hartwegi_ differs from _spinifer_ only in the small size -of the ocelli. _T. s. hartwegi_ resembles _spinifer_ and _asper_, but -differs from _pallidus_, _guadalupensis_ and _emoryi_ in having -blackish spots and ocelli on the carapace and lacking small whitish -spots. _T. s. hartwegi_ resembles _spinifer_, _asper_ and _pallidus_ -but differs from _guadalupensis_ and _emoryi_ in having conical or -knoblike tubercles on the anterior edge of the carapace on large -females. - -_T. s. hartwegi_ differs from the subspecies _asper_, _guadalupensis_ -and _emoryi_ in having a narrower head, and from _emoryi_ in having a -wider carapace. _T. s. hartwegi_ resembles _spinifer_ and _asper_ but -differs from the other subspecies in having the carapace widest at a -plane approximately one-half way back on the carapace. _T. s. -hartwegi_ and _spinifer_ have longer snouts than do _pallidus_ and -_guadalupensis_ or _emoryi_. _T. s. hartwegi_ differs from _asper_ but -resembles the other subspecies in having a relatively longer plastron. - -_Remarks._--The validity of _T. s. hartwegi_ has never been -questioned. It intergrades with _spinifer_ over a broad area -paralleling the Mississippi River. For convenience, specimens -occurring west of the Mississippi River are referred to the subspecies -_hartwegi_. Figure 8 shows much variation in size of ocelli on -different individuals from the same state. For example, UMMZ 92667, -plastral length 6.7 centimeters has a uniform pale brown carapace -lacking any dark marks, whereas UMMZ 92652, plastral length 5.9 -centimeters has some ocelli three millimeters in diameter on the -carapace. Both are from Iowa. One specimen from Kansas, KU 1954 -(Doniphan County, plastral length 11.8 cm.), has ocelli four -millimeters in diameter, and USNM 7648 captured farther west at Fort -Laramie, Wyoming, an adult male having a plastral length of 11.0 -centimeters, has some ocelli five millimeters in diameter on the -carapace. TTC 1090, an adult male from the panhandle of Texas has some -ocelli so much as 5.5 millimeters in diameter. The size of the ocelli -seemingly varies in the same local population. - -Specimens of _T. spinifer_ in the lower Mississippi Valley are -intergrades. Most individuals have small black dots on the carapace; -some have small ocelli (TU 7216, 7501, 11912, 12123-24) interspersed -with black dots (TU 5863), others have black dots confined to the edge -of the carapace (TU 157, 4539, 7105), and still others have no pattern -on the carapace (TU 7506, 13698.1, 10087.6). Two large males (TU -11580, 13025) have large ocelli (approximately five mm. in diameter) -that have nearly black centers. In general, there is more dark -pigmentation than farther north; some specimens have extensive -pigmentation on the ventral surface of the carapace and soft parts of -the body (TU 156, 5648). The dorsal surface of the limbs, especially -the hind limbs, have a bold, black marbling and may be almost -completely black (TU 5484, 5597). Many females, not exceeding plastral -lengths of 7.0 centimeters, have a pale blotched pattern of lichenlike -figures or have ill-defined black dots on the carapace (TU 10087, -13698.13, 13753.15). - -Localities of specimens of _T. spinifer_ occurring in the Mississippi -River drainage in Mississippi are arbitrarily listed under the account -of the subspecies _spinifer_, whereas those in Louisiana (excluding -_pallidus_) are listed under the account of _hartwegi_. - -Neither Over (1943) nor Wheeler (1947:169) record _T. s. hartwegi_, -respectively, from South Dakota or North Dakota; records from the -Missouri River drainage in Montana suggest the occurrence of the -species in that drainage in North and South Dakota. - -_Specimens examined._--Total, 392 as follows: ARKANSAS: _Clay_: UMMZ -70735 (2), 7 mi. S St. Francis. _Crawford_: USNM 95352, Lee Creek, 7 -mi. NW Natural Dam. _Drew_: CNHM 40785. _Lafayette_: KU 2225-29, 2944 -(one of three specimens bearing last catalog number), 2963 (one of -three specimens bearing this catalog number), 2964 (one of two -specimens bearing this catalog number), Lewisville (see remarks under -the account of the subspecies _pallidus_). _Lawrence_: CNHM 8949; -CNHM 12598-600, 12602-04, TU 5855, UI 2413, Imboden; UI 2412, Black -River at Powhatan. _Marion_: TU 14591 (6), White River at Cotter. -_Prairie_: KU 1867, 1869, 1879, 1949-51, 2280-83, 2285-91 (2 specimens -bear catalog number 2287), 2307, 2761-62, 2666, 2826, 2842, 3346-47, -White River at DeValls Bluff. _Pulaski_: UMMZ 96540, Little Rock. -_Saline_: USNM 17823, Saline River at Benton. _Searcy_: UMMZ 92755, -Little Red River, 1.5 mi. SE Leslie. _Yell_: TU 14565, Petit Jean -Creek, 10 mi. N Casa. _County unknown_: CNHM 28566-67, Ouachita River. - -IOWA: _Allamakee_: UMMZ 72556-58, 92642-49, Mississippi River "near" -Lansing. _Appanoose_: UMMZ 92667, Chariton River, 4.3 mi. N. -Centerville. _Decatur_: UMMZ 92651, Grand River, 3.5 mi. WSW Decatur. -_Dickinson_: UMMZ 55249, Milford; UMMZ 92655, Spirit Lake Twp. -_Hamilton_: USNM 9928, Webster City. _Hardin_: UMMZ 92650, Eldora. -_Louisa_: UMMZ 92654, Muscatine Slough, 12 mi. SW Muscatine, Muscatine -County. _Muscatine_: INHS 7675, 5.5 mi. SE Muscatine; USNM 54730-32, -Fairport. _Scott_: CNHM 433, Davenport; UMMZ 92656, Steamboat Slough, -2 mi. N Princeton. _Story_: UMMZ 92653, Squaw Creek at Ames. -_Washington_: UMMZ 92652, English River, 2 mi. E Riverside. - -KANSAS: _Anderson_: KU 52286-87, 3-1/4 mi. E, 1/2 mi. N Colony. -_Atchison_: UMMZ 66939-41, Atchison. _Barber_: KU 17728, 4.5 mi. S Sun -City; KU 41379, 41742, 6 mi. N, 3.5 mi. E Sharon; USNM 100580, -Medicine River, 1 mi. S Lake City. _Cherokee_: KU 1323, Galena. -_Comanche_: KU 18385, 3-4 mi. SE Arrington. _Cowley_: UMMZ 75963, USNM -90441-44, 91022, 100529-30, "near" Winfield. _Doniphan_: KU 1943, -1952-54, Doniphan Lake. _Douglas_: KU 1955-56, Wakarusa River; KU -40176-77, Kansas River at Lawrence. _Franklin_: KU 3290. _Hamilton_: -KU 2990, Syracuse. _Harper_: KU 18159, 1 mi. N Harper. _Kingman_: USNM -95261, 2 mi. E Calista. _Labette_: KU 3339. _Lane_: KU 3738-41, -Pendennis. _Logan_: KU 16531, Smoky Hill River, 3 mi. SW Elkader. -_Meade_: KU 40210, Crooked Creek, 12.5 mi. S, 1-1/4 mi. W Meade. -_Montgomery_: KU 3731-32, Independence; KU 50856, Cherryvale Lake. -_Neosho_: UMMZ 69294, Caneville Creek, 32 mi. N. Parsons, Labette -County. _Osage_: KU 3294-96, Appanoose Creek. _Pratt_: KU 15931-32, -15934, State Fish Hatchery "near" Pratt. _Riley_: KU 48239, McDowell -Creek, WSW Manhattan; UMMZ 64434, "near" Manhattan. _Russell_: KU -3289. _Sedgwick_: UMMZ 95363-65, Wichita. _Shawnee_: USNM 123446, -Kansas River at Topeka. _Stafford_: KU 3758, Little Salt Marsh; KU -41743, 13.5 mi. N, 6 mi. E Stafford. _Trego_: KU 2757, 3769, Smoky -Hill River, 10 mi. N (NNE) Utica, Ness County; KU 51517, Saline River, -5 mi. N, 1/2 mi. E Wakeeney. _Wilson_: KU 56744-45, Verdigris River, 1 -mi. S Altoona. _Woodson_: KU 55295, Neosho River, 1/2 mi. E, 1-1/2 mi. -S Neosho Falls. _County unknown_: USNM 51529. - -LOUISIANA: _Catahoula_: TU 12629, Ouachita River, 4 mi. N -Harrisonburg. _Claiborne_: TU 13080, Caney Lake "near" Summerfield. -_Concordia_: KU 50849, Tensas River at Clayton; TU 16524 (3), USNM -012349, Lake Concordia; USNM 99865, Red River "near" Shaw. _East -Carrol_: TU 827-30, 905, 5644-45, Lake Providence. _Grant_: TU 12735, -Big Creek at Fishville, "near" Pollock. _Jefferson_: TU 5592-98, 7184, -10741, 10171, Mahogany Pond. _Lafourche_: TU 7105, 7132, 7216, 7501, -7505-07, 10087 (14), 11828-29, 11912, 11983 (2), 12123-28, 13502, -13679 (8), 13753 (22), 13766.2, Bayou Lafourche at Raceland. -_Morehouse_: USNM 11631 (2), Mer Rouge. _Natchitoches_: USNM 100420, -Cane River "near" Natchitoches. _Orleans_: TU 16169 (3), Audubon Park, -New Orleans; USNM 029310, "near" New Orleans. _Ouachita_: TU 12916, -12954, 12970-71, 13019, 13025, Bartholomew Bayou at Sterlington; TU -5988, Monroe. _Pointe Coupee_: TU 153, 156-59, 165, 5484, 5513, -5518-19, 5646, 5648, 5651, USNM 100202-12, False River at New Roads. -_Rapides_: TU 14040, Red River at Rapides. _Richland_: OU 25082. _St. -Bernard_: TU 16170, Delacroix Island. _St. Charles_: TU 4539, 4579, -5224, 5990, 11928 (12), 13698 (16), Bayou Gauche between Paradis and -Des Allemands; TU 5863, 11580, Bonnet Carre Spillway at Norco. -_Tensas_: TU 5762, Lake St. Joseph near Newellton. _Union_: USNM -138946, Meridian Creek, 1 mi. E Conway; USNM 138947, Ouachita River, -Alabama Landing. _Parish unknown_: MCZ 1622, Lake St. John (Concordia -or Tensas Parish); USNM 029266, Louisiana? - -MINNESOTA: _Hennepin_: AMNH 4759-60, Fort Snelling. _Lesueur_: KU -46742-43, Waterville, Lake Tetonka. _Winona_: USNM 59263-66, Homer. - -MISSOURI: _Carter_: UMMZ 70737, "near" Van Buren. _Chariton_: UI -17509, Triplett. _Franklin_: USNM 55689. _Gasconade_: UMMZ 95900, -Bourbeuse Creek, 8 mi. S Owensville. _Jefferson_: USNM 95405, Glaize -Creek. _Lewis_: USNM 59279-80, Canton. _Miller_: UMMZ 91929, Barren -Fork Tavern Creek, 5 mi. NW Iowna. _Newton_: UMMZ 82822, Shoal Creek, -12 mi. W Momit. _Phelps_: UMMZ 91930, Bourbeuse River, 10 mi. N St. -James. _Reynolds_: CNHM 35392, Black River at Warner Bay Spring; USNM -55688. _Ripley_: UMMZ 90435. _Shannon_: INHS 6223, Alley Spring State -Park. _St. Charles_: USNM 93089-94, Dardenne Creek, St. Peters. _St. -Louis_: USNM 55685-87, Mississippi River at St. Louis. _Stone_: USNM -55684. _Washington_: USNM 55690. _Wayne_: UI 16554, Sam A. Baker State -Park; UMMZ 95879, St. Francis River at Lodi. _County unknown_ (Wayne -or Butler): UMMZ 83264, Clark National Forest, St. Francis River. - -MONTANA: _Big Horn_: USNM 54421, Crow Agency. _Roosevelt_: USNM 58, -Fort Union (locality reads "Yellowstone, Fort Union"; probably the -Yellowstone River near Fort Union). _Wheatland_: UMMZ 92005, -Musselshell River near Shawmut. _Yellowstone_: USNM 14535, Custer. - -OKLAHOMA: _Alfalfa_: OU 9316, 2 mi. S Cherokee. _Cleveland_: OU 22973, -Norman. _Delaware_: UMMZ 81476, Spavinaw. _LeFlore_: OU 16802, 1.5 mi. -E Zoe. _Osage_: UMMZ 89628, Big Hominy Creek. _Pottawatomie_: OU -25175, 5 mi. SW Shawnee. _Rogers_: OU 7317, Verdigris River, 5 mi. W -Claremore; UMMZ 81473-74, near Garnett, Tulsa County; UMMZ 81475, 4 -mi. NE Inola. _Sequoyah_: OU 9008, 2 mi. NE Gore; TU 13885, Little -Vian Creek, 1 mi. E Vian. _Texas_: OU 5005, 5 mi. SE Guymon. _Tulsa_: -TU 17061, Bird Creek "near" Skiatook, Osage County. _Woods_: CHNM -11809, Waynoka; OU 9432, 2.5 mi. W Waynoka; OU 9579, 9581-82, 1 mi. S -Waynoka. - -TEXAS: _Hansford_: TTC 719, 10 mi. S, 2 mi. W Gruver. _Hutchinson_: -TTC 1090, Carson Creek, Turkey Track Ranch. - -WYOMING: _Goshen_: USNM 7648, Fort Laramie. _Weston_: UMMZ 78080, -Beaver Creek. - -NO DATA: CNHM 21687-88, 22925. SM 142 (locality of Waco, McLennan -County, Texas, believed in error). USNM 7649, 11625, 19622-23, 36412 -(Illinois River). - -_Records in the literature._--ARKANSAS: _Benton_: (Dowling, 1957:37). -_Chicot_: Lake Chicot. _Clark_: Terre Noir Creek, 13 mi. W -Arkadelphia. _Garland_: Ouachita River, Mountain Pine (Conant and -Goin, 1948:7). _Hempstead_: _Jefferson_: (Dowling, _loc. cit._). -_Lawrence_: Black Rock (Dellinger and Black, 1938:46). _Madison_: -_Scott_: _St. Francis_: (Dowling, _loc. cit._). _Washington_: near -Greenland (Dellinger and Black, _loc. cit._). - -COLORADO: _Boulder_: Boulder Creek, E Boulder; Boulder Creek, 6 mi. S -and 1 mi. E Longmont. _Larimer_: Cache la Poudre River. _Logan_: 8 mi. -NE Sterling. _Morgan_: Platte River "near" Fort Morgan. _Otero_: -Purgatoire River at Higbee. _Prowers_: Arkansas River at Lamar. -_Weld_: Poudre River "near" Greeley; Evans. _Yuma_: Bonny Dam, -Republican River (Maslin, 1959:24-25). - -IOWA: _Dickinson_: Little Sioux River, Okoboji Twp. (Blanchard, -1923:24). _Story_: Skunk River, 5 mi. NNE Ames (Conant and Goin, -1948:9). - -KANSAS: _Allen_: Petrolia (KKA). _Barber_: 7 mi. S Sun City. _Butler_: -3 mi. SE Augusta (Burt and Hoyle, 1934:198). _Chase_: 10 mi. SW Olpe; -7 mi. SW Saffordville (Breukelman and Smith, 1946:112). _Cherokee_: -tributary of Spring River, 1 mi. N Riverton (Hall and Smith, -1947:451). _Coffey_: (Smith, 1956:160, symbol on map). _Cowley_: 11 -mi. SE Winfield (Stejneger, 1944:55). _Crawford_: Pittsburg (Hall and -Smith, _loc. cit._). _Doniphan_: "near" Geary (Linsdale, 1927:81). -_Elk_: (Smith, _loc. cit._). _Ellis_: Big Creek (Brennan, 1934:190); -Ellis (Conant and Goin, 1948:2). _Franklin_: Middle Creek, SE part of -county (Gloyd, 1928:135). _Greenwood_: (Stejneger, _op. cit._:54). -_Leavenworth_: Missouri River "near" Fort Leavenworth (Brumwell, -1951:208). _Lyon_: 5 mi. E Emporia (Breukelman and Smith, _loc. -cit._). _Marion_: (Smith, _loc. cit._). _Meade_: Meade County State -Park, _ca._ 13 mi. SW Meade (Tihen and Sprague, 1939:505). _Ness_: -5.5 mi. NW Ness (Breukelman and Smith, _loc. cit._). _Osage_: Marais -des Cygnes River; Long and Jordan Creeks (Clarke, 1958:21). _Reno_: 6 -mi. E Turon. _Sedgwick_: 2 mi. NE Cheney (Burt, 1935:321). _Sheridan_: -State Lake 7 mi. NE Quinter, Gove County (Breukelman and Smith, _loc. -cit._). _Wabaunsee_: Dragoon Creek at Harveyville (Clarke, 1956:215). -_Wallace_: (Burt, 1933:208). _Wilson_: Fall River, 1/2 mi. S Neodesha -(Clarke, _loc. cit._). - -MINNESOTA: _Anoka_: _Benton_: _Chisago_: (Breckenridge, 1944:184, -symbols on map). _Crow Wing_: (Breckenridge, _op. cit._:185). -_Dakota_: (Hedrick and Holmes, 1956:126). _Goodhue_: (Breckenridge, -_op. cit._:184, symbol on map). _Hennepin_: Minneapolis; Lake -Minnetonka (Breckenridge, _op. cit._:187); 5 mi. N. Minneapolis -(Breckenridge, 1955:5). _Houston_: Root River near Hokah. _Lesueur_: -Lake Washington (Hedrick and Holmes, _loc. cit._). _Meeker_: Swan Lake -(Breckenridge, 1957:232). _Pine_: (Breckenridge, 1944:185). _Ramsey_: -_Rice_: _Sherburne_: _Stearns_: (Breckenridge, _op. cit._:184, symbols -on map). _Washington_: just north of Stillwater (Hedrick and Holmes, -_loc. cit._). _Winona_: Winona (Breckenridge, _op. cit._:187). _Yellow -Medicine_: (Breckenridge, _op. cit._:185). _County unknown_ (Goodhue -or Wabasha): Lake Pepin (Breckenridge, _op. cit._:184). - -MISSOURI: _Boone_: east of Ashland (Henning, 1938:92). _Jackson_: -Missouri River "near" Atherton (Anderson, 1942:219). _Jefferson_: -Mississippi River "near" mouth Glaize Creek at Sulphur Springs; Glaize -Creek at Barnhart (Boyer and Heinze, 1934:199). _St. Clair_: Osage -River "near" Osceola. _Vernon_: Marmaton River, 7 mi. N Moundville -(Conant and Goin, 1948:9). - -MONTANA: Yellowstone River (Conant and Goin, 1948:9). - -NEBRASKA: _Adams_: 1 mi. N Ayr (Hudson, 1942:101). _Dawson_: 2 mi. SE -Gothenburg (Gehlbach and Collette, 1959:142). _Franklin_: 2 mi. SW -Naponee. _Gage_: 1 mi. W Barnston. _Hitchcock_: 3 mi. E Stratton. -_Holt_: Elkhorn River "near" Atkinson. _Lancaster_: Lincoln (Hudson, -_loc. cit._). _Lincoln_: 1 mi. S Sutherland (Gehlbach and Collette, -_loc. cit._). _Red Willow_: 14 mi. NW McCook. _Richardson_: 2 mi. S -Rulo. _Wheeler_: 2 mi. W Ericson (Hudson, _loc. cit._). - -OKLAHOMA: _LeFlore_: Wister (Conant and Goin, 1948:9); Shady Pointe -(KKA); Poteau River, 6.5 mi. W Heavener (Trowbridge, 1937:301). -_Tulsa_: Arkansas River "near" Tulsa (Force, 1930:38). - -WYOMING: _Goshen_: Platte River (Conant and Goin, 1948:10). - - -=Trionyx spinifer asper= (Agassiz) - -Gulf Coast Spiny Softshell - -Plates 37 and 38 - - _Aspidonectes asper_ Agassiz, Contr. Nat. Hist. United States, - 1(Pt. 2):405; 2(Pt. 3):pl. 6, fig. 3, 1857. - - _Trionyx spinifer asper_ Schwartz, Charleston Mus. Leaflet, - No. 26:17, pls. 1-3, map 2, May, 1956. - - _Platypeltis agassizii_ Baur, Amer. Nat., 22:1121, 1888. - -_Type._--Lectotype, MCZ 1597; alcoholic female; locality designated as -Pearl River, Columbus, Marion County, Mississippi; received from Mr. -Winthrop Sargent of Natchez, Mississippi. - -_Range._--Southeastern United States except peninsular Florida from -the Florida Parishes of Louisiana east to southern North Carolina; -Gulf Coast drainage including that of Lake Pontchartrain, Louisiana, -eastward to the Apalachicola River system, and Atlantic Coast drainage -including that of the Altamaha River in Georgia northward to the Pee -Dee River drainage in South Carolina (see map, Fig 19). - -_Diagnosis._--Juvenal pattern of black ocelli and spots, and two or -more black, interrupted, lines paralleling rear margin of carapace; -pale postocular and postlabial stripes often united on side of head; -length of plastron short. - -_Description._--Plastral length of smallest hatchling, 2.9 centimeters -(USNM 134244); of largest male, 13.2 centimeters (TU 17117); of -largest female, 27.0 centimeters (TU 13474). - -Blackish marginal rings on carapace number two, three or four -posteriorly, but decrease in number anteriorly; segments of marginal -rings may extend to nuchal region; marginal rings increasingly -interrupted inwardly; pattern of hatchlings having well-defined -marginal rings that are not extensively interrupted (often males), or -having marginal rings broken into small segments or series of dots, -and pale outer margin of carapace marked by ill-defined, hazy, inner -border (often females); conspicuous marginal rings often lacking on -hatchling females; pale rim of carapace not four or five times wider -posteriorly than laterally; carapace having blackish dots, spots, -small ocelli or a combination thereof; marks on carapace of slightly -varying sizes, some occasionally barlike (usually males); some -hatchling females showing pale, irregular blotching on carapace, often -characterized by small lichenlike figures superimposed on blackish -dots. - -Striping on snout variable; pale, dark-bordered stripes usually unite -in front of eyes and form right or acute angle; medial dark borders of -pale stripes on snout not joined anteriorly, broken into segments or -dots, reduced to single median line, united to form straight line -connecting anterior margins of orbits (usually with slight medial -indentation), or absent; pale postocular and postlabial stripes often -joined, relationship variable and on either side of head; side of head -with or without dark markings, sometimes a pale subocular blotch -bordered below by a dark line; pattern on dorsal portions of soft -parts of body contrasting, less so on limbs of hatchlings; pattern of -irregular dark marks, dark streaks usually coincident with digits; -longitudinal streaks often occur on neck; elongate tail of adult males -usually having well-defined, dorsolateral, pale bands with dark lower -border more diffuse than upper border. - -Underparts whitish often with dusky markings on rear of carapace or in -region of bridge; blackish marks often on webbing and portions of -soles and palms, and chin and throat. - -Small conical tubercles along anterior edge of carapace on adult -males; remnants of juvenal pattern usually present on carapace of -large females; conical or knoblike tubercles on anterior edge of -carapace of large females; accessory knoblike tubercles in nuchal -region (a paravertebral pair usually most prominent), and posteriorly -in middle of carapace on large females. - -Ontogenetic variation in PL/HW, mean PL/HW of specimens having -plastral lengths 7.0 centimeters or less, 3.87, and exceeding 7.0 -centimeters, 4.94; ontogenetic variation in CL/CW, mean CL/CW of -specimens having plastral lengths 8.5 centimeters or less, 1.11, and -exceeding 8.5 centimeters, 1.16; mean CL/PCW, 1.71; mean CL/PL, 1.45. - -_Variation._--The sex of some hatchlings can be distinguished by the -pattern on the carapace (see Plate 37 for different patterns), but the -sex of many hatchlings cannot be distinguished on the basis of -pattern. - -In the early stages of this study, I thought that the pattern on the -carapace differed in eastern and western populations, and that the -zone of intergradation was in Alabama. Adult males from the -Tombigbee-Alabama river drainage and westward were noted to have -blackish spots (some slightly ocellate) intermixed with few, if any, -smaller blackish dots, whereas the adult males from east of the -Tombigbee-Alabama river drainage had many small, black dots intermixed -with slightly larger, mostly ocellate marks (see Plate 38, left, top -and bottom, for contrast); also, hatchlings from western populations -were never observed to have four marginal rings. On the basis of -pattern, I would have thought that the individual having many ocelli, -that lacks correct locality data and that is photographed by Stejneger -(1944:Pl. 26), came from Georgia or South Carolina; but, the pattern -(_op. cit._:Pl. 27) of a specimen, probably an adult male, from South -Carolina, resembles the pattern on adult males from Louisiana. The -differences noted above are probably due to individual variation -rather than geographic variation. - -Color notes taken from life of a freshly-killed adult male (TU 16071, -Louisiana) are: carapace olive, spots blackish, outer rim buff; top of -head olive, postocular and postlabial stripes yellow with blackish -borders, stripes on snout buff with blackish borders; dorsal ground -color of soft parts of body pale olive-green, larger marks blackish, -ground color laterally toward juncture of pattern and immaculate -undersurface, and toward insertions of neck and limbs becoming -yellowish; webbing on hind limbs having reddish tinge; dorsolateral -bands on tail yellow with blackish borders; undersurface whitish; chin -and throat olive-green with blackish marks; becoming buff then whitish -posteriorly. - - [Illustration: FIG. 20. Basicranial length and ratio of greatest - diameter of internal choanae to least width of maxillary - bridge (IC/MB) on 30 skulls of _T. ferox_ (open circles), - 26 of _T. spinifer_ (crosses), and 12 of the _agassizi_-form - (solid circles; half shaded circle represents holotype of - _agassizi_). Skulls of the _agassizi_-form tend to have - slightly smaller internal choanae than those of _spinifer_ - or _ferox_.] - -Occasional specimens have only one definite dark line paralleling the -rear margin of the carapace. Schwartz (1956:16) reported that -Charleston Museum No. 55.159.26 has only one solid line at the margin -of the carapace, and I received an adult male (KU 47120) reported to -have come from the Pearl River that is aberrant in not having more -than one dark marginal line. USNM 95191, a large stuffed female from -the Pearl River is mentioned by Stejneger (1944:59, Pl. 17) as having -marks that "assume the form of short lines parallel with the -submarginal ring"; I examined this specimen and noted that it had only -one dark marginal line. Stejneger (_op. cit._:64) mentioned another -from the Pearl River drainage, and Crenshaw and Hopkins (1955:20) -wrote that some individuals from Georgia have only one dark marginal -line. Presumably MCZ 1606 (now in the Albany Museum) recorded by -Stejneger (_op. cit._:52) as _Amyda s. spinifer_ from Columbus, -Georgia, is another specimen. - - [Illustration: FIG. 21. Basicranial length and greatest width of - alveolar surface of maxilla on 52 skulls of _T. spinifer_ (open - circles) and 11 of the _agassizi_-form (solid circles; half shaded - circle represents holotype of _agassizi_). Most skulls of the - _agassizi_-form that exceed 43 mm. in basicranial length have a - more expanded, alveolar surface of the maxilla than skulls of - _spinifer_ of approximately the same size. All skulls exceeding - 50 mm. are those of females.] - -Some skulls of soft-shelled turtles from streams of the Atlantic Coast -drainage, including the skull of the holotype of _Platypeltis_ (= -_Trionyx_) _agassizi_ Baur (MCZ 37172, Pl. 54), show at least two -differences from other skulls of _asper_ and from those of other -subspecies of _T. spinifer_. Figure 20 shows that skulls of _agassizi_ -tend to have slightly smaller internal choanae (ratio IC/MB) than -those of _T. spinifer_ and _T. ferox_; there is seemingly little -difference between skulls of _ferox_ and _spinifer_, and little, if -any, ontogenetic variation. Figure 21 shows that most skulls of the -_agassizi_-form that exceed 43.0 millimeters have a more expanded, -alveolar surface of the maxilla than skulls of _spinifer_ of -approximately the same size; most skulls exceeding a basicranial -length of 43.0 millimeters, and certainly all skulls exceeding 50.0 -millimeters are those of females. Stejneger (1944:Pl. 30) also has -provided photographs of a skull of the _agassizi_-form. It is of -interest that of the 12 _agassizi_-form skulls (MCZ 37172; USNM 8708, -029034, 51981, 66859, 71681, 91282, 91310-11, 92521, 92583-84) that I -examined some resemble _ferox_ (Neill, 1951:9) in having the alveolar -surfaces of the jaws broadened, and the greatest width at the level of -the quadratojugal (Table 3, Plate 54); also, the localities of all 12 -skulls are within the geographic range of _ferox_. Skulls of _ferox_, -however, have conspicuously broadened alveolar surfaces of the jaws -only when they exceed in length the largest skulls of _agassizi_. The -differences of skulls of the _agassizi_-form possibly reflect -isolation in the Atlantic Coast drainage, and an adaptation in feeding -habits. So far as I can ascertain, individuals occurring in rivers of -the Atlantic Coast drainage in Georgia and South Carolina (referable -to _agassizi_) do not differ consistently in external characters from -individuals of _T. s. asper_ that occur westward in the Apalachicola -drainage. - -_Comparisons._--_Trionyx s. asper_ can be distinguished from all other -subspecies of _T. spinifer_ by usually having more than one black line -paralleling the rear margin of the carapace. This character and the -frequent fusion of the postlabial and postocular stripes on the side of -the head distinguish _asper_ from _spinifer_ and _hartwegi_. _T. s. -asper_ differs from _pallidus_, _guadalupensis_ and _emoryi_ in having -blackish spots and ocelli on the carapace, and lacking whitish dots or -tubercles. _T. s. asper_ resembles _spinifer_, _hartwegi_ and _pallidus_ -but differs from _guadalupensis_ and _emoryi_ in having conical -tubercles along the anterior edge of the carapace in large females. For -additional differences see accounts of other subspecies. - -Of the subspecies of _T. spinifer_, _asper_ has a proportionately wide -head that is closely approached in the subspecies _guadalupensis_ and -_emoryi_; _T. s. asper_ differs from _guadalupensis_ and _emoryi_ in -having a wider carapace, and resembles _hartwegi_ and _spinifer_, but -differs from the other subspecies in having the carapace widest at a -plane approximately one-half way back on the carapace. _T. s. asper_ -differs from the other subspecies in having the shortest plastron. - -_Remarks._--Stejneger (1944:72-74) has discussed the history of Baur's -_Platypeltis agassizi_. Briefly, Agassiz's description of _Platypeltis -ferox_ wherein he (1857:402) states that "The young ferox [Pl. 6, fig. -3] has two or three concentric black lines separating the pale margin -...," was applicable to _T. s. asper_. Agassiz mentioned also that the -young of his _Aspidonectes asper_ (_op. cit._:406) "as in Platypeltis -ferox, ... has ... two or three black lines separating the pale rim of -the posterior margin, ..."; however, _A. asper_ was distinguished -chiefly by the "... prominent warts of the bony plates (_loc. cit._)." -Because the description of the pattern of _ferox_ resembled that of -_asper_, the validity of _asper_ was not agreed upon by all workers. -Boulenger (1889:245, footnote 1) referred to _asper_ as a species that -required "... further investigation." - -Baur (1888:1121) realized that Agassiz's description of _ferox_ was not -that of _Testudo ferox_ Schneider, and regarded the description of -Agassiz as applying to a new species, which he named _Platypeltis -agassizii_; Baur (_op. cit._:1122) also recognized _asper_, referring it -to the genus _Aspidonectes_. Baur designated a specimen from Georgia -(the only individual seen by him) as the type of _agassizi_ (Stejneger, -_op. cit._:73, footnote); this specimen is now MCZ 37172. Five years -later (1893:218), Baur discussed generic relationships of trionychids, -seemingly only on the basis of skulls (holotype of _agassizi_ not -mentioned), and referred _agassizi_ to the resurrected genus -_Pelodiscus_ Fitzinger, 1835, which was distinguished from the other two -American genera that Baur recognized (_Platypeltis_ and _Amyda_) by -having the "Posterior nares reduced in size by the inner and posterior -extension of the maxillaries." Baur also transferred _asper_ to the -genus _Platypeltis_, and restricted the type locality of that species to -"Lake Concordia, La." (_op. cit._:220); the type locality of _agassizi_ -was restricted to "Western Georgia" (_loc. cit._). - -The name-combination, _Pelodiscus agassizi_, was not generally accepted. -Hay (1892:144) and Siebenrock (1924:188) referred _agassizi_ to the -genus _Trionyx_. Hay regarded _agassizi_ as a full species (see -discussion by Stejneger, 1944:73), whereas Siebenrock considered it a -subspecies of _spiniferus_; both authors regarded _asper_ as a synonym -of _agassizi_. Neither _asper_ nor _agassizi_ was mentioned in the first -three editions of the Check List of North American Amphibians and -Reptiles (Stejneger and Barbour, 1917, 1923, 1933); the same authors in -the fourth (1939:171, 172) and fifth editions (1943:212, 213) listed -_agassizi_ as a full species, and _asper_ as a subspecies of -_spinifera_. Stejneger (1944) used the same arrangement as set forth in -the fourth and fifth editions of the Check List, and distinguished -_agassizi_ on the basis of cranial characters, namely, the small size of -the internal choanae, the greater width of the alveolar surface of the -lower jaw, and the position of the suture between the palatine and -basisphenoid relative to the posterior edge of the temporal fossa. Neill -(1951:9) regarded the peculiarities of the _agassizi_-type skull as -inconstant, but recognized _agassizi_ (and _asper_) as a subspecies of -_ferox_. Crenshaw and Hopkins (1955) showed that _asper_ did not -intergrade with _ferox_. Schwartz showed that _agassizi_ did not -intergrade with _ferox_, and regarded _agassizi_ as a synonym of _T. s. -asper_ (1956:17), but stated that _agassizi_ possessed "wider crushing -surfaces on the maxillae than does _T. s. asper_, even when skulls of -the same size and sex are compared" (_op. cit._:9). - -The holotype of _Platypeltis agassizi_ (MCZ 37172) is a dried adult -female consisting of shell, skull and limb bones; the carapace is -approximately 300 millimeters long (Schwartz, _loc. cit._). I have -examined only the skull of MCZ 37172 (Plate 54), and it is the largest -of 12 _agassizi_-type skulls I have seen. The basicranial length is 72.5 -millimeters, and the greatest width, which occurs at the level of the -quadratojugals, is 52.9 millimeters. The _agassizi_-type skulls have -been discussed under the subsection on variation. - -The type locality of _T. s. asper_, Lake Concordia, Louisiana (lower -Mississippi River drainage) as restricted by Baur (1893:220), is in an -area of intergradation of three subspecies of _Trionyx spinifer_ where -most individuals are not typical of _asper_. The syntypes, the -designation of MCZ 1597 as a lectotype, and Pearl River, Columbus, -Marion County, Mississippi, as the type locality have been discussed -elsewhere (Webb, 1960). - -The range of _T. s. asper_ overlaps that of _T. ferox_ in Georgia and -South Carolina. The two species remain distinct in the area of overlap -of their geographic ranges (Crenshaw and Hopkins, 1955:16; Schwartz, -_op. cit._:5). _Trionyx s. asper_ intergrades with _T. s. hartwegi_ and -_T. s. spinifer_ in the lower Mississippi Valley (Conant and Goin, -1948:11). - -However, there are few specimens available that indicate intergradation -of _asper_ with the _spinifer-hartwegi_ complex in the lower Mississippi -River drainage; this may be due to the fact that _asper_ inhabits -waterways that do not drain into the Mississippi River. Perhaps -intergradation is more prevalent than the morphological basis that I -have relied upon indicates; in any event, there are few specimens that -have more than one dark marginal line (which is the only character that -is unique for _asper_) from the lower Mississippi drainage. A young male -(TU 11928.9) from Bayou Gauche between Paradis and Des Allemands, St. -Charles Parish, Louisiana, has a pattern on the carapace resembling that -of _asper_; several other small softshells (TU) are available from the -same locality but none shows more than one dark marginal line. Another -specimen (USNM 95192), a young female from a barrow pit of the Big Black -River (Mississippi River drainage), Madison County, Mississippi, -resembles _asper_ in having more than one marginal ring. Of three large -females from Moon Lake, an ox-bow of the Mississippi River in Coatopa -County, Mississippi (AMNH 5285-86, 5289), only 5289 shows evidence of -two marginal lines. USNM 73669 (Greenwood, LeFlore County, Mississippi) -also indicates intergradation in that the spots tend to be linear just -inside the dark marginal line, but the specimen more closely resembles -the _hartwegi-spinifer_ complex rather than _asper_. - -There seems to be little adumbration of the dark marginal lines of -_asper_ in populations from the lower Mississippi River drainage. -Blackish spots and ocelli vary in size and there are many kinds of -pattern on the carapace. Soft-shelled turtles inhabiting the Mississippi -River and its tributaries in Louisiana and Mississippi certainly -represent an intergrading population of _spinifer_ and _hartwegi_, and, -to a lesser extent, of _asper_. Soft-shelled turtles inhabiting the -Pearl River drainage and rivers that drain into Lake Pontchartrain -immediately adjacent to the east are predominantly _asper_. - -Specimens having localities from the Pearl River and Lake Pontchartrain -drainages are listed under the account of _asper_ and are referred to -that subspecies on the distribution map; specimens from the Mississippi -drainage in Mississippi are referred to _spinifer_. - -One specimen (UMMZ 59198, Bradley County, Tennessee), from the Tennessee -River drainage where _T. s. spinifer_ occurs, deviates markedly from -_spinifer_ and suggests intergradation. UMMZ 59198, plastral length 4.8 -centimeters, has ocelli in the center of the carapace only two -millimeters in diameter, a distinct but interrupted, second marginal -ring consisting of spots, and the pale postlabial and postocular stripes -in contact on both sides of the head. - -_Specimens examined._--Total 110, as follows: ALABAMA: _Barbour_: UMMZ -113038, Chattahoochee River, Eufala. _Cherokee_: ANSP 24592, "near" -center of Terrapin Creek. _Conecuh_: UMMZ 70736, Murder Creek, -Castleberry. _Escambia_: TU 15823, Escambia River, 1 mi. N Sardine; UMMZ -70734, Escambia River at Flomaton. _Henry_: TU 15630, 3 mi. NW jct. Echo -Farm Rd. and Rt. 136 on Echo Farm Rd. _Lowndes_: UMMZ 67759, Pintlalla -Creek. _Mobile_: MCZ 1608 (2), 1608A, Mobile. _Sumpter_: USNM 83996, 3 -mi. SE Coatopa. _Tuscaloosa_: TU 14673 (5), Black Warrior River, 17.5 -mi. SSW Tuscaloosa; UA 52-1085, Cottondale. _Walker_: KU 50843, 50851, -TU 17137, Mulberry Fork, Black Warrior River, 9 mi. E Jasper. - -FLORIDA: _Calhoun_: KU 50837-38, Chipola River, 4 mi. N Scott's Ferry; -TU 16689 (4), Chipola River "near" Blountstown. _Escambia_: TU 13474, -15869 (3), 16584, Escambia River, 1.2 mi. E Century. _Okaloosa_: TU -15661, Blackwater River, 4.3 mi. NW Baker on Route 4. _Santa Rosa_: AMNH -44621, Blackwater River, Milton. _Walton_: UMMZ 110421, Pond Creek, 4 -mi. SW Florala, Covington County, Alabama. - -GEORGIA: _Baker_: TU 15889 (3), USNM 134243-48, Flint River "near" -Newton; USNM 30822. _Baldwin_: USNM 8708, Milledgeville. _Bryan_: TU -15090, Canouche River, 2.3 mi. W Groveland. _Chatham_: USNM 51981, -92583-84, Savannah. _Chattooga_: UMMZ 113037, tributary of Chattooga -River, Lyerly. _Decatur_: KU 50839-42, Flint River, 1.5 mi. S -Bainbridge. _Fulton_: UMMZ 53037, Roswell. _Lincoln_: USNM 91282-83, -above Price Island, Savannah River. _Murray_: UMMZ 59196, 9 mi. N Spring -Place. _Pulaski_: TU 14882, Ocmulgee River, 4.3 mi. SE Hawkinsville. -_Richmond_: USNM 66859, Augusta. _Whitfield_: UMMZ 74209, Cohulla Creek, -Prater's Mill "near" Dalton. _County unknown_: MCZ 37172; UMMZ 109864, -Flint River at mouth of Dry Creek; USNM 029034. - -LOUISIANA: _East Baton Rouge_: LSU 11, 1643-44, City Park Lake in Baton -Rouge; TU 17237, Amite River "near" Baton Rouge. _St. Tammany_: TU 6356, -headwater creek of Bayou Lacombe; TU 16071, USNM 66147, mouth of -Tchefuncta Creek in Lake Pontchartrain. _Tangipahoa_: TU 13623, 3.1 mi. -W Hammond; USNM 68054, Robert. _Washington_: KU 50840, 50846, TU 17117, -Pearl River at Varnado. _Parish unknown_ (East Baton Rouge or -Tangipahoa): UMMZ 95614, Manchac. - -MISSISSIPPI: _Chickasaw_: USNM 115981, Chookatonkchie Creek. _Clarke_: -USNM 79350-51, 1 mi. W Melvin, Choctaw County, Alabama; USNM 100805, -Enterprise. _Forrest_: WEB 55-586, 1 mi. S Hattiesburg. _Hancock_: AMNH -46780; WEB 54-651, Hickory Creek "near" Kiln. _Lauderdale_: UMMZ 74681, -9 mi. W Meridian; UMMZ 90130, Lake Juanita, 15 mi. W Meridian. -_Lawrence_: KU 47120, TU 17307.1, Pearl River, 9 mi. S Monticello; USNM -7653-54, Pearl River at Monticello. _Lee_: CM 31904, Verona; USNM -115979, Cower's Area near Guntown. _Madison_: USNM 95191, 95193-94, -Pearl River. _Marion_: MCZ 1597, Pearl River at Columbus (designated -type locality). _Pearl River_: CM 21100, Pearl River, 20 mi. W -Poplarville; TU 14362, Hobolochito Creek, 1 mi. N Picayune. _Perry_: WEB -55-580, Beaver Dam Creek, 1 mi. N Richton. _Walthall_: KU 50844, Bogue -Chitto River, Dillon. - -SOUTH CAROLINA: _Abbeville_: USNM 7650, Abbeville? (reported by Pickens, -1927:113; locality considered in error by Stejneger, 1944:50; USNM 7650 -having only one dark marginal line paralleling rear margin of carapace -is possibly an aberrant specimen--see page 495 of present account). -_Greenwood_: USNM 71681, 73668, Greenwood. _McCormick_: USNM 91310-12, -Savannah River, 5 mi. W Plum Branch; USNM 92521, near Parksville. -_Richland_: AMNH 70724-25, Broad River, Columbia. - -NO DATA: USNM 8359 (erroneously reported from Madison, Indiana by -Yarrow, 1882:29 and Hay, 1892:145; see discussion by Cahn, 1937:200, and -Stejneger, 1944:73-75); USNM 131859. - -_Records in the literature._--ALABAMA: _Coffee_: Elba (KKA). _Marengo_: -Tombigbee River near Demopolis. _Mobile_: Fig Island (Löding, 1922:47). - -FLORIDA: _Jackson_: Chattahoochee River, 8 mi. SE Butler. _Leon_: -Ochlocknee River, NW of Tallahassee (Goin, 1948:304). - -GEORGIA: _Bartow_: Etowah River below Allatoona Dam, _ca._ 4 mi. ESE -Cartersville (Crenshaw and Hopkins, 1955:15). _Berrien_: (Knepton, -1956:324). _Emanuel_: Ogeeche River (Schwartz, 1956:19). _Fulton_: Nancy -Creek, Atlanta (Dunston, 1960:278). _Gwinnett_: _Irwin_: (Knepton, _loc. -cit._). _Jenkins_: Ogeeche River near Buckland Creek jct., 2.5 mi. S -Millen. _Liberty_: Camp Stewart, 4 mi. N Hinesville. _Morgan_: Lake -Rutledge (Schwartz, _loc. cit._). _Muscogee_: Columbus (Stejneger, -1944:52). _Wayne_: Altamaha River, 5 mi. N Mt. Pleasant (Schwartz, _loc. -cit._). _Wilcox_: Ocmulgee River, 3-4 mi. SSE Abbeville (Crenshaw and -Hopkins, _op cit._:16, footnote; Schwartz, _loc. cit._). - -MISSISSIPPI: _George_: Whiskey Creek (Cook, 1946:185). _Harrison_: near -Biloxi. _Jackson_: Pascagoula Swamp, _ca._ 40 mi. E. Biloxi (Corrington, -1927:101). _Jones_: Eastabuchie. _Lee_: Cain Creek Bottom. _Lincoln_: -Old Brook Creek. _Lowndes_: Tombigbee River, Camp Henry Pratt and -Columbus; Lake Park, Columbus. _Pearl River_: 21 mi. SW Poplarville; 10 -mi. W Poplarville; 4 mi. W Poplarville. _Wayne_: Trigg Area (Cook, _loc. -cit._). - -NORTH CAROLINA: _Mecklenburg_: Catawba River near Charlotte (Schwartz, -1956:20). - -SOUTH CAROLINA: _Aiken_: Savannah River, 10 mi. SW Jackson. _Allendale_: -Savannah River, Fennell Hill, 2 mi. S US 301. _Anderson_: Pendleton. -_Bamberg_: South Edisto River, Cannon's Bridge, 5 mi. from Bamberg. -_Berkeley_: 2.5 mi. W Pinopolis. _Charleston_: Charleston. _Clarendon_: -Upper Lake Marion at US 301; Lake Marion, 13 mi. SW Manning; 3.3 mi. S -Jordan; 6.3 mi. S Jordan; Wyboo Creek, 8.5 mi. from Manning. _Colleton_: -Edisto River (Schwartz, 1956:19-20). _Darlington_: Pee Dee River, -Society Hill (Stejneger, 1944:72). _Dorchester_: Edisto River, 17 mi. -from Summerville; Edisto River, 14 mi. W Summerville; Edisto River, 2.5 -mi. S Hart's Bluff. _Fairfield_: 1 mi. N Peak, Newberry County. -_Georgetown_: North Santee River, 1 mi. above US 17. _McCormick_: Little -River near McCormick; Little River, 3 mi. NE Mt. Carmel. _Laurens_: -Enoree River, 3 mi. S Cashville, Spartanburg County; Enoree River, 9.4 -mi. N Clinton. _Orangeburg_: Edisto River, Orangeburg. _Saluda_: -Batesburg; Lake Murray; Little Saluda River; 5 mi. from Saluda. _County -unknown_: Upper Lake Santee (Schwartz, _loc. cit._). - - - -=Trionyx spinifer emoryi= (Agassiz) - -Texas Spiny Softshell - -Plates 43, 44 - - _Aspidonectes emoryi_ Agassiz (in part), Contr. Nat. Hist. United - States, Vol. 1, Pt. 2, p. 407; Vol. 2, Pt. 3, pl. 6, figs. 4-5, - 1857. - - _T[rionyx] s[pinifer] emoryi_ Schwartz, Charleston Mus. Leaflet, - No. 26, p. 11, 1956. - -_Type._--Lectotype, USNM 7855; alcoholic (sex undetermined); obtained -from the Río Grande near Brownsville, Texas, in the course of the -Mexican Boundary Survey under the command of Colonel Wm. H. Emory. - -_Range._--Southwestern United States and northern México; the Río -Grande drainage in Texas, New Mexico and northern México; the Río San -Fernando and Río Purificación drainages in northeastern México; the -Colorado River drainage in Arizona, New Mexico, and southern Nevada -(see map, Fig. 19). - -_Diagnosis._--Juvenal pattern of white dots, not encircled with dusky -or blackish ocelli, confined to posterior third of carapace; pale rim -of carapace conspicuously widened, four to five times wider -posteriorly than laterally; a dark triangle in front of eyes, base -line connecting anterior margins of orbits; pale postocular stripe -interrupted leaving conspicuous pale, usually dark-bordered, blotch -just behind eye. - -_Description._--Plastral length of smallest hatchling, 2.5 centimeters -(USNM 7632); of largest male, 13.0 centimeters (KU 2914, 3125, 3150); -of largest female, 22.0 centimeters (TNHC 8023, 8104). - -Carapace pale brownish or tan, lacking whitish dots on anterior half; -whitish dots confined to posterior third of carapace, sometimes -lacking posteriorly, especially on juveniles; small, blackish dots -rarely occurring on surface of carapace, usually confined to margins -when present; pale rim of carapace four to five times wider -posteriorly than laterally. - -Pattern on snout rarely variable, consisting of pale stripes extending -forward from eyes that have only their outer borders darkened and a -straight or slightly curved, dark line that connects anterior margins -of orbits; few, if any, dark markings in subocular and postlabial -region; pattern on side of head having few contrasting marks, often of -nearly uniform coloration; postocular stripe usually interrupted; -anterior segment of postocular stripe just behind eye usually -dark-bordered; posterior segment usually not dark-bordered or sharply -distinguished from background; pattern on dorsal parts of soft parts -of body contrasting, of relatively small dark marks; dark streaks -often coincident with digits. - -Underparts whitish, occasionally having blackish dots or smudges on -posterior part of carapace, in region of bridge, or on lateral parts -of chin and throat; few dark marks often on webbing of limbs and on -palms and soles. - -Small, flattened or wartlike, tubercles that occasionally have sharp -tips along anterior edge of carapace on adult males; tubercles -flattened, scarcely elevated, never conical along anterior edge of -carapace on large females; whitish, knoblike tubercles often present -posteriorly in middle of carapace and in nuchal region on large -females; mottled and blotched pattern sometimes contrasting on -carapace of large females; whitish dots of juvenal pattern often -visible through overlying blotched pattern of large females. - -Ontogenetic variation in PL/HW, mean PL/HW of specimens having -plastral lengths 7.0 centimeters or less, 3.68, and exceeding 7.0 -centimeters, 5.19; ontogenetic variation in CL/CW, mean CL/CW of -specimens having plastral lengths 8.5 centimeters or less, 1.17, and -exceeding 8.5 centimeters, 1.27; mean CL/PCW, 2.18; mean HW/SL, 1.43; -mean CL/PL, 1.37. - -_Variation._--Ten topotypes (six males, three females, one juvenile) -from Brownsville, Texas (BCB 7465-73, 7564), have the following -characteristics: pale rim widened posteriorly as described above; -females (plastral lengths 9.8, 10.2 and 11.7 cm.) having blackish -marks in pale rim, which are absent in males of corresponding size; -interrupted postocular stripe with pale blotch behind eye; postocular -pale blotch having blackish borders or not; dark triangular mark on -snout in front of eyes; white dots present only on posterior third of -carapace; carapace of females grayish, blotched pattern not -contrasting; carapace of males paler, greenish-gray; undersurface -immaculate except 7468 and 7472 that have blackish flecks at bridge -and, on 7472, blackish marks that extend posteriorly onto ventral -surface of carapace; tubercles along anterior edge of carapace -flattened and rounded in adult males, more knoblike in females; -largest specimen, BCB 7472, female, plastron 11.7 centimeters long. - -_T. s. emoryi_ varies more than any other subspecies of _Trionyx -spinifer_. A large series of males and females (KU) from the Salt -River (Colorado River drainage), near Phoenix, Arizona, is -characterized by many adult males having indistinct white dots on -posterior half of carapace; blotching on carapace of females of -contrasting lichenlike figures, but usually non-contrasting and pale -brownish or tan; pale rim of carapace distinct from ground color of -carapace in largest female (KU 2905, plastron 21.5 cm. in length), but -having dark or dusky markings: dark interorbital stripe often lacking. -AMNH 58370 (Nevada) and UMMZ 92006 (Arizona) also have the dark line -connecting the anterior margins of the orbits interrupted; seemingly -the dark interorbital line is most often interrupted in those -softshells inhabiting the Colorado River system of Nevada and Arizona. - -Other variant individuals are: TU 14453.2, 14462 and 3696 having the -plastron extending slightly farther forward than the carapace, thus -resembling _T. ferox_; UMMZ 54021 and CNHM 39999, hatchlings, lacking -distinct whitish dots on posterior half of carapace; UI 43509 and KU -39991 having stained (brown or blackish) claws; and, CNHM 6810, an -adult male, lacking a spinose (sandpapery) carapace. I am unable to -discern geographic variation in these or other characters. - -The ground color of the carapace on some individuals from the Pecos -River (TU, Terrell County, Texas) is grayish and in contrast with the -pale rim (Pl. 44). UI 43509 from the Río Florida, La Cruz, Chihuahua, -a female, has a dark brownish carapace with little evidence of a -blotched pattern except on the pale rim of the carapace. A female and -adult male from the Río Sabinas, Coahuila (MSU 905-06), also show -considerable darkening on the dorsal surfaces; the pale rim is evident -but not in sharp contrast to the coloration of the carapace. Notes -taken on the freshly-killed Sabinas individuals are: male--carapace -olive-gray; dorsal surface of soft parts of body olive-green to -grayish, a bright yellow suffusion on limbs and neck; female--carapace -and soft parts of body dark olive, laterally pale yellow; the plastron -extends slightly farther forward than the carapace in both sexes. - -Notes on coloration (judged to be the most common or "normal" type) -of living _emoryi_ from the Río Mesquites, central Coahuila, are: -Adult male (KU 53753)--pale rim butterscotch yellow; marginal line -blackish; whitish dots on pale brown or tan carapace; soft parts of -body olive or olive-green, slightly darker on head and paler -(yellowish) on hind limbs; pale areas on side of head pale yellow, -having tint of orange on neck; ventral surface white, yellow laterally -on neck. Adult female (KU 53754)--carapace having contrasting blotched -and mottled pattern of pale browns and tans; soft parts of body olive -brown, darker brown blotching on head; dorsal surface of limbs -olive-green having pale areas lemon yellow and webbing butterscotch -yellow; side of neck and head, chin and throat pale lemon yellow; -ventral surface white having slight red tinge to groin and soft parts -posteriorly; underside of carapace near edge pale yellow. - -Softshells from the Río Grande in the Big Bend region of Texas, and -the Río Conchos in Chihuahua differ from other specimens of _emoryi_. -Fifteen adult males, KU 51187-201 (no females in sample), were taken -from the mouth of the Río San Pedro at Meoquí, Chihuahua (see KU -51194, Pl. 44). They are noteworthy because of a conspicuous orange or -orange-yellow on the side of the head. Another relatively consistent -character is the blackish tip of snout (excepting 51199), although the -degree (palest on 51190) and extent of pigmentation posteriorly on the -snout is variable. Eleven males, KU 51175-85, from approximately 100 -miles northeastward in the Río Conchos near Ojinaga, Chihuahua, also -have the bright orange on the side of the head; the tip of the snout -is not blackish, although in some it is slightly darkened. Three -females, KU 51174, 51186 (from Ojinaga) and 51173 (from 8 mi. S, 16 -mi. W Ojinaga), lack the orange on the side of the head; KU 51186 has -a plastral length of 8.0 centimeters, whereas the other two females -have the same plastral length of 16.5 centimeters (larger than any -male). Nineteen adult males, KU 51965-72, 51980-90, from the Río -Grande near Lajitas also have the orangish coloration on the side of -the head, whereas twenty females, KU 51954-64, 51973-79, 51991-92 -(three smaller than largest male) lack the coloration. The tip of the -snout is not blackish on any turtle in the series from Lajitas. The -smallest female, from Lajitas, having a plastral length of 6.9 -centimeters, has a mottled carapace. - -The orange of males is most conspicuous in the pale postocular and -postlabial areas; the stripes of the snout (distally) and the color of -the neck at its juncture with the immaculate ventral surface are -orange-yellow. The orange coloration is confined to males (all -examined were sexually mature) and is probably not of seasonal -occurrence (see comments under secondary sexual variation). I have not -noticed this coloration in other males of the subspecies _emoryi_; -however, long-preserved males might be expected to lack the orange -color; the specimens mentioned above were initially preserved in -alcohol. KU 51179 (plastral length 8.2 cm., from Ojinaga) is the -smallest sexually mature male of the species _spinifer_ that I have -seen. Another character of note is the generally greater development -of the plastral callosities (resembling _muticus_) than in other -subspecies of _spinifer_ or specimens of _emoryi_; three small adult -males (KU 51177, 51990, 51987, plastral length 9.3, 9.9 and 9.1 cm., -respectively) have large hyoplastral and hypoplastral callosities that -appear to touch medially, and callosities on the epiplastron and both -preplastra. - -On July 8, 1953, an adult male of _T. spinifer_ was removed from a -hoop-net set in the Río Purificación at Padilla, Tamaulipas, México. I -was particularly impressed by the lack of whitish dots on the dark -carapace; the following notes were taken from the freshly-killed -specimen: carapace a uniform dark olive, lacking white dots and having -a yellowish rim widest posteriorly; tubercles on anterior edge of -carapace only slightly raised, inconspicuous; top of head olive with -few dots and streaks; a well-defined yellowish postocular stripe not -conspicuously interrupted; sharp contrast between dark olive on side -of head and pale ventral coloration; yellowish-orange ventrolaterally -on head; an uninterrupted slightly-curved line connecting the anterior -margins of the orbits; carapace pear-shaped; underparts whitish, -lacking markings. This specimen has since been destroyed. The only -other specimen I have seen from this locality is a hatchling (UMMZ -69412, Pl. 43), which has a pale brownish or tan carapace that lacks -whitish dots; it resembles _emoryi_ in other characters. Although the -absence of whitish dots is not distinctive, its combination with the -uniform dark olive carapace in adult males and the fact that the Río -Purificación is an isolated drainage system, suggests that -soft-shelled turtles from that river system may warrant further -taxonomic study. - -_Comparisons._--From all other subspecies of _spinifer_, _T. s. -emoryi_ can be distinguished by having a pale rim on the carapace that -is four to five times wider posteriorly than it is laterally. This -character, unique for _emoryi_, combined with patterns on the snout, -side of head and carapace that are subject to little variation, permit -ready identification of the subspecies _emoryi_. _T. s. emoryi_ -resembles _pallidus_, and _guadalupensis_ and differs from _spinifer_, -_hartwegi_ and _asper_ in having whitish tubercles or dots on the -carapace. _T. s. emoryi_ resembles _guadalupensis_ but differs from -_pallidus_, _spinifer_, _hartwegi_ and _asper_ in lacking conical -tubercles along the anterior edge of the carapace on large females. -For additional differences see accounts of other subspecies. - -Some populations of _T. s. emoryi_ resemble _T. muticus_ in the size -at which sexual maturity is attained and in the development of the -plastral callosities. _T. s. emoryi_ has a wide head that resembles -that of _T. ferox_, _T. ater_, _T. s. asper_ and _T. s. -guadalupensis_; _T. s. emoryi_ also resembles _T. ferox_ and _T. ater_ -but differs from the other subspecies of _T. spinifer_ and _T. -muticus_ in having a narrower carapace. _T. s. emoryi_ resembles _T. -s. guadalupensis_, _T. s. pallidus_ and _T. ater_, and differs from -the other subspecies of _spinifer_ and _T. muticus_, in having the -carapace widest farther posteriorly than one-half way back on the -carapace. _T. s. emoryi_ resembles _T. ferox_ in having the shortest -length of snout of the subspecies of _spinifer_. The plastron is -shorter than in _T. ferox_, longer than in _T. s. asper_, and about -the same length as in _T. muticus_ and the other subspecies of _T. -spinifer_. - -_Remarks._--Agassiz (1857, 1:407-08) did not designate a holotype in -the original description of _Aspidonectes emoryi_; specimens are -mentioned from the lower Río Grande of Texas, near Brownsville, and a -stream of the Río Brazos drainage in Williamson County, Texas. The -description is applicable to _T. s. emoryi_ as herein restricted, -except for the statement that the white tubercles of young specimens -are "encircled by faint black lines"; that statement is presumably -based on the juveniles from Williamson County. _T. s. emoryi_ does not -occur in Williamson County, Texas. Barbour and Loveridge (1929:225) -listed MCZ 1909-10 and 1627 as cotypes. Stejneger (1944:65) mentioned -MCZ 1909, 1913 and USNM 7855 as cotypes; the legend for Plate 20 (_op. -cit._) refers to a drawing that "corresponds fairly closely with the -type (MCZ 1910) collected at Brownsville, Texas, by Col. Emory." - -The syntypic series consists of seven specimens--MCZ 1627 (two -specimens) from Williamson County, Texas; MCZ 1909 (three specimens) -and 1910 from Brownsville, Texas; and USNM 7855 from Brownsville, -Texas. The listing of number 1913 by Stejneger is considered a -_lapsus_ for 1910 as MCZ 1913 is catalogued as a _Graptemys -geographica_ (in letter dated November 17, 1959 from Dr. Ernest E. -Williams). Stejneger's reference to MCZ 1910 as the type is considered -unintentional and an inadequate designation of a lectotype. - -In the "remarks" column of the USNM museum catalog, number 7855 is -referred to as "Ag. Type." USNM 7855 is here designated as lectotype -of _Trionyx spinifer emoryi_. The lectotype is a young specimen -(female?) that is not easily sexed by external characters; the -plastron measures (in centimeters) 6.3 in length, the carapace 8.2 in -length and 7.0 in width, and the head 1.4 in width. The carapace is -pale brown having inconspicuous whitish dots posteriorly and a pale -rim that is approximately 6.8 times wider posteriorly (4.1 mm.) than -it is laterally (0.6 mm.). The slightly curved dark line connecting -the anterior margins of the orbits is dimmer than the dark lines that -extend forward from the eyes. The pale postocular stripes having -blackish, dotted borders are interrupted; there are no other markings -on the side of the head. The ventral surface is immaculate except for -a few dark dots on the right side of the carapace; the ground color is -pale brown or tan, but the upper layer of skin can be scraped away -revealing an underlying pale lavender-cream ground color. The -tubercles along the anterior edge of the carapace resemble small -rounded warts. - -MCZ 1910 is an adult male _T. s. emoryi_ having a plastron 10.7 -centimeters in length. The carapace is pale brown having a relatively -smooth anterior edge, inconspicuous whitish tubercles posteriorly, and -a pale rim five times wider posteriorly than laterally; the pattern on -the head resembles that of _emoryi_. - -Each of three hatchlings of _T. s. emoryi_, 3.4, 3.5 and 3.9 -centimeters in plastral length, bears an MCZ catalogue number of 1909. -The carapaces are dark tan or gray having pale rims 3.7, 5.2 and 5.2 -times wider posteriorly than laterally, and white dots absent or -obscure posteriorly; two specimens have small blackish dots -paralleling the pale rim posteriorly. The patterns on the heads are -referable to _emoryi_. - -The two juvenal syntypes (5.2 and 6.1 cm. in plastral length) from -Williamson County, Texas, are both catalogued as MCZ 1627, but only -one of these bears a catalogue number. The two softshells are not -_emoryi_, and are more nearly like _T. s. guadalupensis_ than _T. s. -pallidus_. Actually, they are from an area of intergradation between -those subspecies (see comments concerning intergradation under the -accounts of the subspecies _pallidus_ and _guadalupensis_). White -spots occur on the carapaces anteriorly and posteriorly, the larger -(more posterior) of which are encircled with dusky ocelli. The -carapace of the small specimen (bearing no number) is brown having a -few, small black specks intermixed with the white spots. The carapace -of the large specimen is pale lavender and has a more obscure pattern -than the other specimen. - -After Agassiz's description, _emoryi_ was accepted as a distinct -species. Neill (1951:15) suggested that _emoryi_ was subspecifically -related to _T. ferox_. Crenshaw and Hopkins (1955) and Schwartz -(1956), however, demonstrated that _ferox_ was a distinct species; -_emoryi_ has since been considered a subspecies of _T. spinifer_. - -Two specimens having blackish dots on the carapace, indicate -relationship with _T. s. guadalupensis_. USNM 7638, a hatchling, has -large whitish dots surrounded by blackish dots confined to the -posterior half of the carapace, and the locality for this specimen is -merely Río Bravo (= Río Grande). CNHM 47366, a hatchling from Sierra -de las Palmas (Sierra de Santa Rosa, La Palma), Coahuila, has a few, -small, blackish dots, irregularly spaced, on the anterior half of the -carapace, but other dots more evenly distributed on the posterior half -where they are intermixed with whitish dots. The drawing of the dorsal -view of a hatchling _emoryi_ (Agassiz, 1857:Pl. 6, Fig. 4) shows a -sprinkling of blackish dots on the anterior half of the carapace. A -hatchling from Eagle Pass (USNM 116578) does not have a noticeably -widened pale rim posteriorly on the carapace, and is not -distinguishable from _pallidus_. See account of _T. s. guadalupensis_ -for further comments on intergradation. - -A soft-shelled turtle that was obtained in the Sacramento River by -three fishermen, near Sacramento, California, was named _Aspidonectes -californiana_ by Rivers (1889:233). A comparison (with _Aspidonectes -spinifer_ and _A. emoryi_) of certain features of the skull was -largely prepared by Baur and included in the description (_op. -cit._:234-35); seemingly, the most trenchant character of the skull of -_californiana_ was the enlarged alveolar surfaces of the jaws. This -feature prompted Baur (1893:220) to refer _californiana_ to the genus -_Pelodiscus_, which also included _agassizi_ (skulls also having jaws -with enlarged alveolar surfaces) and several Old World species. Van -Denburgh (1917) discussed the origin of the specimen that formed the -basis of River's description and concluded that it was brought over -from China. Siebenrock (1924:192) and Mertens and Wermuth (1955:389) -listed _Aspidonectes californiana_ as a synonym of _emoryi_. River's -description is not that of _emoryi_; the enlarged alveolar surfaces of -the jaws, and the dark carapace having tubercular ridges suggest a -resemblance to _T. ferox_. The papillae on the neck are not found in -any American species. Miller (1946:46, footnote 2) believed that "it -obviously was introduced, apparently from China," and cited Pope -(1935:61), who declared the specimen to represent _Trionyx sinensis_. - -Schmidt (1924:64) first reported the occurrence of _T. s. emoryi_ west -of the continental divide in Arizona and suggested that it was highly -probable that the species had been introduced near Phoenix in recent -years. Cowles and Bogert (1936:42) mentioned a species of softshell -occurring in the Boulder Dam region and presumed the species to be -native to Asia and introduced by the Chinese. Linsdale and Gressitt -(1937:222) determined the status of the species in the Colorado River -drainage as _T. s. emoryi_. The discussions by Dill (1944:179-81) and -Miller (1946:46) indicate that _emoryi_ was introduced into the Gila -River (Colorado River drainage) in western New Mexico near the turn of -the century. - -_T. s. emoryi_ and _T. ater_ are the only kinds of softshells -occurring in México. The colloquial name for soft-shelled turtles in -México is "tortuga blanca." This name is also used in reference to the -Central American river turtle, _Dermatemys mawei_, which occurs on the -east coast of México as far north as Veracruz. - -_Specimens examined._--Total 275, as follows: ARIZONA: _Maricopa_: -CNHM 4768, KU 2214-19, 2803, 2824, 2837, 2903-07, 2909-16 (2914, 2 -specimens), 2918-29, 3118-27, 3129, 3147-56, USNM 71627, Salt River, -Phoenix. _Pinal_: UI 37713, Gila River, 6 mi. E Winkleman; UMMZ -92006-07, Gila River, 1/2 mi. below Coolidge Dam; UMMZ 105824, San -Pedro River about 1 mi. above confluence with Gila River. - -NEVADA: _Clark_: AMNH 58370, Boulder City boat landing, Lake Mead; TU -15802, Virgin River, Mesquite. - -NEW MEXICO: _Eddy_: KU 15938, Carlsbad; KU 48217-18, Black River -Village. _Grant_: AMNH 79911, Gila River, 8 mi. NE Cliff. - -TEXAS: _Brewster_: CNHM 39999, Tornillo Creek near jct. with Río -Grande; KU 51954-92, Lajitas; TCWC 4291, UMMZ 66471, USNM 45545, -103678, Boquillas; INHS 7975, UMMZ 114360, Hot Springs. _Cameron_: BCB -7564-73, CNHM 5339-40, 6810, MCZ 1909 (3), 1910, TU 11479-80, -11561-62, UMMZ 54021, 105209-13 (Brownsville Lake), USNM 7642, 7644, -7855, Brownsville; BCB 5121, 3 mi. S Harlington. _El Paso_: UMMZ -85085, El Paso; USNM 7641, 7701, El Paso del Norte. _Hudspeth_: USNM -20846, Fort Hancock on Río Grande. _Kinney_: CNHM 26090, Río Pinto W -of Bracketville; USNM 26426-36, Fort Clark. _Loving_: TTC 1143, Red -Bluff Lake just below dam on Pecos River. _Maverick_: TU 3696-97, UMMZ -116578, Eagle Pass. _Presidio_: TTC 628 (2), 632 (2), 3 mi. WNW -Lajitas, Brewster County. _Terrell_: TNHC 7997, 8022-23, Chandler -Ranch, 30 mi. S Sheffield, Pecos County; TNHC 8104, Dunlap Ranch, 25 -mi. SE Sheffield, Pecos County; TU 14453 (7), 14462 (2), 15415, 15423, -15586, Pecos River near jct. with Independence Creek; USNM 104240, -Pecos River "near" Dryden. _Val Verde_: TTC 113, Pecos River. _Webb_: -TNHC 19788, 42 mi. NW Laredo; USNM 109078-79, Laredo. _Zapata_: UI -19332, "near" Zapata. _County unknown_: MCZ 1628, USNM 7635-36, 7854; -USNM 7637-38, Río Bravo (= Río Grande). - -CHIHUAHUA: KU 51173, 8 mi. S, 16 mi. W Ojinaga; KU 51174-86, 1 mi. NW -Ojinaga; KU 51187-201, Río Conchos at mouth of Río San Pedro near -Meoquí; UI 43508-09, Río Florida, La Cruz. - -COAHUILA: CNHM 26054, Sta. Helena Canyon of Río Grande; CNHM 28846, -"near" Músquis; CNHM 55657, Río Alamos, Rcho. de la Gacha; CNHM 47366, -Sierra de Santa Rosa, La Palma; CNHM 47367, 55661, Cuatro Ciénegas; -CNHM 55658-60, Rcho. de los Borregos near Juarez; KU 33523, La Presa -Don Martín; KU 39991, 39993, 8 mi. N, 2 mi. W Piedras Negras; KU -39992, 2 mi. W Jiménez; KU 46907, 16 km. S Cuatro Ciénegas; KU -46913-16, 10 km. S Cuatro Ciénegas; KU 53752-54, Río Mesquites, 8 mi. -W Nadadores; KU 53757, 8.5 mi. SW Cuatro Ciénegas; MSU 905-06, Río -Sabinas, 1 mi. E Sabinas. - -NUEVO LEON: CNHM 1874, 2191, Rodriguez; UMMZ 69411, Río Conchos, 9 mi. -N Linares. - -TAMAULIPAS: CM 3037, Nuevo Laredo. UMMZ 7614-20, 7622-25, 7628, 7630, -7632-33, Matamoros; UMMZ 69412, Río Purificación, N of Ciudad -Victoria. - -NO DATA: MCZ 1629 (2), NHB 1032. - -_Records in the literature._--ARIZONA: _Greenlee_: Gila River, Duncan -(Miller, 1946:46); "near" Sheldon (Dill, 1944:180). _Mohave_: Pierce's -Ferry just below lower end of Grand Canyon (Cowles and Bogert, -1936:42); 1.5 mi. upstream (Virgin River) from Mesquite, Clarke -County, Nevada (Hardy and Lamoreaux, 1945:168); Lake Havasu on -Colorado River (Dill, 1944:180). _Yuma_: Colorado River at Headgate -Rock Dam (Dill, _op. cit._:179). - -CALIFORNIA: _Imperial_: California Lakes (Cowles and Bogert, 1936:42); -Palo Verde; Colorado River at Laguna Dam (Dill, 1944:180). - -NEVADA: _Clark_: observed just north of Black Canyon (Cowles and -Bogert, _loc. cit._); Colorado River, 6 mi. N California line -(Linsdale, 1940:255). - -NEW MEXICO: _Chaves_: Bitter Lakes Wildlife Refuge, 12 mi. NE Roswell -(Bundy, 1951:314). _Dona Ana_: Río Grande near Mesilla Dam (Little and -Keller, 1937:221). - -TEXAS: _Brewster_: Río Grande at Castolon (Minton, 1959:38). _Val -Verde_: mouth of Devil's River (Brown, 1950:250). - -BAJA CALIFORNIA: Colorado River delta, 7 mi. E Cerro Prieto; Imperial -Irrigation District, Alamo Canal, 15 mi. S Internat'l Boundary and -Salfatana Canal, 1 mi. N Black Butte (Linsdale and Gressitt, -1937:222). - -COAHUILA: San Juan (Schmidt and Owens, 1944:103). - -Hitherto, soft-shelled turtles of the species _Trionyx spinifer_ from -the southern and southwestern United States having a pattern of white -dots on the carapace have been relegated to the subspecies _emoryi_, -but my examination of soft-shelled turtles from Texas has indicated -that _T. s. emoryi_ as previously conceived, is a composite of three -subspecies. It is necessary, therefore, to recognize two new -subspecies. - - -=Trionyx spinifer guadalupensis= new subspecies - -Guadalupe Spiny Softshell - -Plates 41 and 42 - -_Holotype._--UMMZ 89926, alcoholic adult male; obtained 15 miles -northeast Tilden, McMullen County, Texas (Pl. 41, bottom, left). - -_Paratypes._--Forty-two specimens: ANSP 16717 (hatchling), no data; -USNM 78515-16 (hatchlings), Colleto Creek, Victoria County, Texas; TU -10143-45, 10148, 10150-59, 10161-65 (adult males), TU 10176, 10833 -(immature males), TU 10147, 10149, 10155 (immature females), TU 10160 -(adult female), Guadalupe River, 9 miles southeast Kerrville, Kerr -County, Texas; UMMZ 89915-21, 89924-27 (adult males), UMMZ 89922-23 -(immature females), same locality as holotype; UMMZ 92752 (immature -female), San Antonio River, 3 miles west-northwest Goliad, Victoria -County, Texas. - -_Description of holotype._--Carapace nearly circular, widest at level -of posterior border of hypoplastra; margin entire; dorsal surface -"sandpapery" to touch; pale rim separated from ground color of -carapace by well-defined, blackish line that is wavy and narrowly -interrupted posteriorly and anteriorly; pale rim approximately 1.8 -times wider posteriorly (5.4 mm.) than laterally (3.0 mm.); pale rim -increasingly narrower anteriorly, absent in nuchal region; tubercles -in nuchal region low, scarcely elevated, lacking sharp tips; ground -color of carapace olive having pattern of whitish spots and small -tubercles; most whitish tubercles inconspicuous pinpoints; other small -tubercles in center of whitish spots, mostly approximately 2 -millimeters in diameter; largest white spot 3.4 millimeters in -diameter; most white spots surrounded by blackish ocelli or parts -thereof; whitish spots distributed over entire surface of carapace; -certain features of bony carapace evident through overlying skin; -carapace highest in region of second and third neurals, forming -obtuse, gently sloping, vertebral, keel; undersurface of carapace -butterscotch yellow, lacking markings; maximum length, 16.5 -centimeters; greatest width, 13.5 centimeters. - -Plastral surface butterscotch yellow, lacking markings, extending -slightly farther forward than carapace; anterior and posterior lobes -rounded; anterior lobe slightly truncate; certain features of bony -elements of plastron visible through overlying skin; maximum length of -plastron, 12.0 centimeters. - -Head, extended to posterior level of eyes, terminating in flexible -snout; septal ridges projecting into each rounded nostril; jaws -closed, each covered by fleshy lips except anteriorly where horny -portions exposed; dark triangular mark in front of eyes, base line -connecting anterior margins of orbits forming series of dots; pale -stripes extending forward from eyes having faint inner, blackish -borders; eyelids partly open having blackish dots; pale subocular -blotch on right side of head having border of black dots. - -Forefeet and hind feet well-webbed having five digits each; each limb -having nails on first three digits; each forelimb with four -antebrachial scales, three of these having free edge; each hind limb -with two horny scales, one smooth on posterodorsal surface and other -with free edge on posteroventral surface; pattern toward insertion of -forelimbs indistinct. - -Tail terminating in flexible point; penis exposed; cloacal opening -extending beyond posterior edge of carapace; tail olive above bordered -by blackish marks; few black dots laterally on left side. - -Undersurface of soft parts of body buff, lacking markings; few dark -marks posteriorly on webbing of limbs, encroaching on soles and palms. - -_Range._--Southcentral Texas in the drainage systems of the Nueces and -Guadalupe-San Antonio rivers; the Colorado River drainage in Texas is -inhabited by a population that more closely resembles _guadalupensis_ -than _pallidus_. See comments under subsection entitled "Remarks" and -Fig. 19. - -_Diagnosis._--Juvenal pattern of white dots that are conspicuous on -anterior half of carapace, and usually as large as those on posterior -half; white dots, sometimes 3 millimeters in diameter, encircled with -blackish ocelli in adult males. - -_Description._--Plastral length of smallest hatchling, 3.3 centimeters -(ANSP 16717); of largest male, 13.5 centimeters (TU 10162); of largest -female, 22.0 centimeters (TU 10160). - -Hatchlings having white dots on anterior half of carapace; white dots -anteriorly nearly as large as those posteriorly, encircled with -blackish ocelli, and conspicuous on dark background (ANSP 16717, Pl. -41; USNM 78515-16; Stebbins, 1954:181, Pl. 26B), or smaller than those -posteriorly, not encircled with dusky ocelli, and inconspicuous on -pale background (TNHC 1446); pale rim of carapace less than four times -as wide posteriorly as laterally. - -Adult males resembling holotype; size of white tubercles on carapace -variable; most, if not all, tubercles surrounded by narrow blackish -ocelli, or parts thereof; largest white tubercles or dots in most -specimens exceeding one millimeter and in some specimens three -millimeters in diameter (TU 10163); white dots often slightly elongate -(UMMZ 89917, 89920, 89926; TU 10152, 10145); juvenal pattern of white -dots seemingly more contrasting in _guadalupensis_, owing to dark -ground color of carapace, than in _pallidus_ or _emoryi_ that have -pale brown or tan carapaces; small tubercles along anterior edge of -carapace rounded, obtuse, wartlike, never conical; sharp tips often -lacking (TU 10153). - -Large females often having whitish spots on anterior half of carapace -(TU 10160, Pl. 42, upper, right; 10142); carapace dark having -ill-defined mottled and blotched pattern; tubercles along anterior -edge of carapace low, rounded, rarely equilateral, never conical; -small blackish dots rarely on surface of carapace (UMMZ 89923). - -Pattern on side of head and snout of little diagnostic value; -postocular stripe usually interrupted, but configuration variable, -consisting of pale anterior, dark-bordered segment (just behind eye); -posterior segment of postocular stripe usually less well-defined and -generally blending with adjacent ground color; pale postocular stripe -sometimes uninterrupted and dark-bordered throughout its length (TU -10157, 10159, 10176); pattern on dorsal surface of snout variable; -pattern usually consisting of uninterrupted dark line (slightly curved -anteriorly) connecting anterior margins of orbits (TU 10161, 10164, -10159, 10143), or dark line interrupted (TU 10153, 10154, 10176), -absent (TU 10163), or present in addition to dark inner borders of -pale stripes that extend anteriorly from eyes (TU 10149, 10162); -small, often fine, dark markings, on dorsal surface of limbs, -especially forelimbs; ventral surface of plastron and soft parts of -body usually whitish, lacking markings; small blackish spots -occasionally in region of bridge (TU 10149); dark marks occurring on -webbing of limbs and often encroaching on soles and palms. - -Ontogenetic variation in PL/HW, mean PL/HW of specimens having -plastral lengths 7.0 centimeters or less, 3.83, and exceeding 7.0 -centimeters, 5.18; ontogenetic variation in CL/CW, mean CL/CW of -specimens having plastron lengths 8.5 centimeters or less, 1.14, and -exceeding 8.5 centimeters, 1.22; mean CL/PCW, 2.11; mean HW/SL, 1.38 -(including subspecies _pallidus_); mean CL/PL, 1.37. - -_Variation._--Two hatchlings (ANSP 13447, Bexar County; TNHC 1446, -McMullen County) more closely resemble _pallidus_ than -_guadalupensis_. - -Some individuals from the Colorado River drainage have features -suggesting those that are characteristic of _pallidus_. Large females -have obtuse, knoblike somewhat triangular-shaped tubercles along the -anterior edge of the carapace, which are never conelike (TU 14439-40, -10187, 16036.1; BCB 6010). The tubercles along the anterior edge of -the carapace are more elevated than in turtles from drainage systems -west of the Colorado. Whitish spots are usually absent anteriorly on -the carapace, but may be evident through the mottled pattern of large -females (BCB 6010, plastral length, 19.7 cm.). The pale postocular -stripe is usually interrupted, whereas the dark line connecting the -anterior margins of the orbits is usually not interrupted; the two -characters last mentioned show alliance with _guadalupensis_. - -The carapace of hatchlings from the Colorado River is pale having -whitish dots, smaller anteriorly than posteriorly, which may be -encircled with dusky ocelli (TNHC 20257) or not (ANSP 11889, BCB 5055, -SM 3282). Many hatchlings are not distinguishable from _pallidus_ -(TCWC 7262, TNHC 4975, SM 4924, 6106). I have not seen hatchlings from -the Colorado River that resemble ANSP 16717. - -The pattern on the carapace of adult males from the Colorado River -drainage resembles that of _guadalupensis_ (Pl. 41, bottom, right) but -the whitish dots are usually smaller and may not be encircled with -blackish ocelli (BCB 4066, TU 14485). An adult male (TU 14476) from -the South Fork of the Llano River has whitish dots three millimeters -in diameter and encircled with blackish ocelli (_guadalupensis_), -whereas another adult male (USNM 83690) from a tributary of the -Colorado, the South Concho River, resembles _pallidus_. - -Eight specimens from the San Saba River (TU 14419 [6 specimens], -14439-40), that range in plastral length from 6.8 to 17.0 centimeters -are impressive because of the dark brownish coloration on the -carapace. The smallest individual, which is also the only male in the -series, is paler. The mottled and blotched pattern on the females is -therefore not contrasting; the largest females have elevated whitish -prominences in the center of the carapace posteriorly. An immature -male (UMMZ 70348) from the South Concho River also has a dark brown -carapace, and lacks white dots. The dark coloration of the carapace of -these specimens recalls the TU series of _T. s. emoryi_ from the Pecos -River, Terrell County, Texas. - -Color notes taken from a freshly-killed adult female from the Llano -River, two miles west Llano (TU 16036.1, Pl. 42), are: pattern on -carapace of dark olive or blackish marks that form an irregular -reticulum or marbling on a paler background that varies from brownish -to buff and has an orange or reddish tinge in some areas; small -whitish spots posteriorly; pale rim yellowish, evident only at sides -of carapace; dorsal surface of soft parts of body olive-green, -becoming paler with yellowish tinge toward insertions of limbs and -neck; no contrasting pattern on limbs or neck and head; yellowish on -sides of body; ventral surface whitish lacking dark marks, yellowish -at region of bridge, axillary region and on neck; chin olive-yellow. - -_Comparisons._--_T. s. guadalupensis_ can be distinguished from all -other subspecies of _T. spinifer_ in having: (1) large white dots, -sometimes three millimeters in diameter, on a dark background usually -surrounded with blackish ocelli and conspicuous on the anterior half -of the carapace (some as large as those on posterior half) in adult -males, and (2) whitish dots on the anterior half of the carapace, in -hatchlings, that are often encircled with dark ocelli. _T. s. -guadalupensis_ resembles _pallidus_ and _emoryi_ in having white -tubercles or dots on the carapace and therein differs from _spinifer_, -_hartwegi_ and _asper_. _T. s. guadalupensis_ resembles _pallidus_ but -differs from _emoryi_ in having a pale rim that is less than four -times wider posteriorly than laterally. _T. s. guadalupensis_ -resembles _emoryi_ but differs from _pallidus_, _spinifer_, _hartwegi_ -and _asper_ in having along the anterior edge of the carapace -tubercles that are flattened or wartlike prominences often lacking -sharp tips in adult males; these tubercles are never conical in large -females. - -_T. s. guadalupensis_ has a wide head, a feature shared with the -subspecies _asper_ and _emoryi_, but differs from _emoryi_ in having a -wider carapace. _T. s. guadalupensis_ resembles _emoryi_ and -_pallidus_ but differs from the other subspecies in having the -carapace widest farther posterior than one-half the length of the -carapace. The length of snout in _pallidus_ and _guadalupensis_ is -shorter than in _spinifer_ and _hartwegi_ but is longer than in -_emoryi_. _T. s. guadalupensis_ differs from _asper_ but resembles the -other subspecies in having a relatively long plastron. - -_Remarks._--Some individuals of _guadalupensis_ have characteristics -that are applicable to _emoryi_. TNHC 12352 (Llano River) a hatchling, -has conspicuous white dots confined to the posterior third of the -carapace; the pale rim, however, is not widened posteriorly. TU 10156 -(Guadalupe River) has a conspicuously widened pale rim on the carapace -that is approximately 3.4 times wider posteriorly (8.5 mm.) than -laterally (2.5 mm.). - -_T. s. guadalupensis_ more closely resembles _pallidus_ than _emoryi_. -Turtles living in rivers that drain into the Gulf of Mexico east of -the Guadalupe-San Antonio river system successively show increasing -resemblance to _pallidus_ from west to east. - -The expression of intergradation between _guadalupensis_ and -_pallidus_ is of a clinal nature that involves parallel changes in the -pattern on the snout, side of head, limbs (to a lesser degree), -tuberculation along the anterior edge of the carapace, size of whitish -tubercles or dots, and the distinctness of the blackish ocelli that -surround the whitish dots on the carapace. These characters form a -well-marked gradation or cline that extends over a considerable area. -There is, however, no continuous environmental gradient because the -populations are relatively isolated by occupying adjacent drainage -systems. The sharpest break in the gradation of characters mentioned -above occurs between the Colorado River and Brazos River drainages. -The population of softshells in the Colorado River drainage is -actually an intergradient one, but more closely resembles -_guadalupensis_, whereas the population in the Brazos River drainage -more closely resembles _pallidus_. For convenience the turtles -inhabiting the Colorado River drainage are referred to _guadalupensis_ -and those in the Brazos River drainage to _pallidus_. Some individuals -from farther west than the Colorado River drainage will resemble -_pallidus_, and a few individuals from father east than the Brazos -River drainage will resemble _guadalupensis_. - -The gradation of some of the characters mentioned above terminates in -the subspecies _emoryi_. It, however, has characters not found in -_pallidus_ or _guadalupensis_, and is more distinct from either of -those subspecies than either is from each other; the difference in -characters as well as the break in the gradient of characters between -_guadalupensis_ in the Nueces River drainage and _emoryi_ in the Río -Grande drainage is greater than that between _guadalupensis_ in the -Colorado and _pallidus_ in the Brazos River drainages. - -I have refrained from designating individuals between these three -subspecies (_emoryi_, _guadalupensis_ and _pallidus_) as "intergrades" -on the distribution maps, and only mention (in text) those individuals -whose characters show a decided tendency toward the adjacent -subspecies. For further comments on intergradation see the account of -_T. s. pallidus_. - -_Specimens examined._--Total 97, as follows: TEXAS: _Bandera_: KU -50834, Hondo Creek, 4 mi. W Bandera; TNHC 797-98, 7 mi. SW Medina. -_Bexar_: ANSP 13447, Helotes; MCZ 4587; USNM 10789, 71009, San -Antonio. _Borden_: BCB 4066, 7 mi. N Vincent. _Brown_: TNHC 7262, 1 -mi. E Brownwood. _Comal_: USNM 7700, New Braunfels. _Dawson_: TNHC -21594-95, 10 mi. E Lamesa. _Frio_: USNM 7747, Río Seco. _Gillespie_: -TU 10185, 10187, 10205, Beaver Creek, "near" Doss. _Hays_: AMNH -29950-52, San Marcos. _Kerr_: SM 2553, headwaters Turtle Creek; TU -10142-45, 10147-65, 10176, 10833, Guadalupe River, 9 mi. SE Kerrville. -_Kimble_: BCB 5052-55, 6010, 3 mi. SE Telegraph; TU 14476, South Fork -Llano River, 1.5 mi. SE Telegraph; TU 14485, Llano River, 10 mi. W -Junction. _Lavaca_: SM 2554-55, 2559, 3 mi. NNE Hope. _Llano_: TNHC -12352, TU 16036 (2), Llano River, 2 mi. W Llano. _McMullen_: TNHC -1446, 10 mi. W Simmons, Live Oak County; UMMZ 89915-27, 15 mi. NE -Tilden. _Matagorda_: ANSP 11889, Matagorda. _San Saba_: SM 6106; TU -14419 (6), 14439-40, San Saba River, 11 mi. NNW San Saba. _Tom Green_: -SM 3282, UMMZ 70348, USNM 83690, South Concho River at Christoval. -_Travis_: SM 659-60, 8.5 mi. from mouth of Onion Creek in Colorado -River near Austin; SM 4924, Onion Creek; TNHC 4975, Upper Bull Creek; -TNHC 20257, Marshall Ford Dam. _Victoria_: CM 3118, Black Bayou; UMMZ -92752, San Antonio River, 3 mi. WSW Goliad; USNM 78515-17, Colleto -Creek, Guadalupe River. _County unknown_: ANSP 16717; TNHC 1404. - -_Records in the literature._--TEXAS: _Bandera_: 24 mi. WNW Medina -(Brown, 1950:250). _Burnet_: Colorado River (Strecker, 1909:8). -_Gillespie_: 20 mi. N Harper (Brown, _loc. cit._). _Kendall_: Cibolo -Creek at Boerne (Strecker, 1926:8). _Kerr_: Guadalupe River, 3 mi. -above Kerrville (TCWC 474, listed in card file). _Mason_: 12 mi. NE -Mason (TCWC 3303, listed in card file). _Matagorda_: Bay City (Brown, -_loc. cit._). _Real_: (Stejneger, 1944:66). _Wilson_: Cibolo River, 30 -or 40 mi. N Sutherland Springs (Strecker, 1935:23). - - -=Trionyx spinifer pallidus= new subspecies - -Pallid Spiny Softshell - -Plates 39 and 40 - -_Holotype._--TU 484, alcoholic adult male; obtained from Lake Caddo, -Caddo Parish, Louisiana on June 27, 1947, by Fred R. Cagle and party -(Pl. 39, lower, left). - -_Paratypes._--Forty-two specimens: TU 481, 490, 678 (hatchlings), TU -381, 472, 488 (immature males), TU 475, 478, 486, 1232, 1291, 10170 -(adult males), TU 399, 487 (immature females), TU 469 (adult female), -Caddo Lake, Caddo Parish, Louisiana; TU 15818 (immature male), TU -15819 (adult male), Cross Lake, Caddo Parish, Louisiana; TU 1253, -13211 (adult males), TU 13266 (immature female), Sabine River, 8 miles -southwest Merryville, Beauregard Parish, Louisiana; TU 13281-82 (adult -males), TU 13280, 13265 (immature females), TU 13303-04, 13306 (adult -females), Sabine River, 8 miles southwest Negreet, Sabine Parish, -Louisiana; SM 2375 (adult male), Wallace Bayou, De Soto Parish, -Louisiana; TU 1122 (adult male), Lacassine Refuge, Louisiana; UMMZ -92754 (adult male), 5 miles west Iowa, Calcasieu Parish, Louisiana; KU -40174-76, OU 27297 (adult males), OU 27290 (immature female), Lake -Texoma, 2 mi. E Willis, Marshall County, Oklahoma; KU 50832 -(hatchling), mouth of Caney Creek, 4 miles southwest Kingston, -Marshall County, Oklahoma; CNHM 15474 (immature female), Kiowa County, -Oklahoma; KU 2966-67 (immature females), KU 2934, 2947 (adult males), -KU 2973 (adult female) Lewisville, Lafayette County, Arkansas. - -_Description of holotype._--Carapace circular, widest at level of -posterior edge of hyoplastra; margin entire; dorsal surface -"sandpapery" to touch; pale rim separated from ground color of -carapace by well-defined, slightly ragged, blackish line; pale rim -approximately 2.1 times wider posteriorly (4.7 mm.) than it is -laterally (2.2 mm.); pale rim increasingly narrower anteriorly, absent -in nuchal region; tubercles along anterior edge of carapace triangular -with sharp tips becoming flattened and inconspicuous at level of -insertions of arms; ground color of carapace brownish having pattern -of small whitish tubercles; most whitish tubercles inconspicuous, of -pinpoint size, giving surface of carapace "sandpapery" effect; largest -white tubercles posteriorly, approximately 1.2 millimeters in -diameter; whitish tubercles smaller anteriorly, largest approximately -0.6 millimeters in diameter; whitish tubercles tend to form two -parallel lines coincident with longitudinal sutures of neurals -posteriorly in center of carapace; certain features of bony carapace -evident through overlying skin; carapace highest in region of third -and fourth neurals, forming obtuse, gently sloping, vertebral keel; -undersurface of rear margin of carapace whitish having pinkish tinge -and no markings; maximum length, 16.8 centimeters; greatest width, -14.3 centimeters. - -Plastral surface extending slightly farther forward than carapace, -whitish having pinkish tinge and no dark markings; anterior and -posterior lobes rounded, posterior lobe more acutely; certain features -of bony elements of plastron visible through overlying skin; maximum -length, 12.2 centimeters. - -Head extended, terminating in flexible snout; septal ridges projecting -into each rounded nostril; tip of snout darkened; jaws open, each -covered by fleshy lips except anteriorly where horny portions exposed; -dark triangular mark in front of eyes, base line uninterrupted, -slightly curved anteriorly, connecting anterior margins of orbits; -eyelids having blackish dots, especially upper, closing eyes; small -blackish dots on dorsal surface of head; pale postocular stripe -dark-bordered, interrupted; pale portion of stripe traversed by black -line; pale subocular blotch margined by broken blackish border; side -of head having contrasting blackish marks on pale background; -postlabial stripe having lower blackish border on right side of head; -chin with ill-defined marks, not contrasting on grayish background; -well-defined, ragged black line on side of neck separating dorsal -coloration from immaculate ventral coloration; small dark dots on -dorsal surface of neck; dorsal surface of head and neck olive or -brownish, becoming paler laterally and toward insertion of neck; -maximum width of head, 2.1 centimeters. - -Forefeet and hind feet well-webbed each having five digits; each limb -having nails on first three digits; each forelimb with four -antebrachial scales, three of which have free edge; each hind limb -with two horny scales, one smooth on posterodorsal surface and other -with free edge on posteroventral surface; contrasting pattern of -blackish marks, mostly roundish, on pale background of grayish-white. - -Tail terminating in flexible point; penis partly exposed; cloacal -opening extending beyond posterior edge of carapace; tail having -dorsal grayish band flanked by interrupted blackish lines; dark marks -encroaching ventrally at tip of tail. - -Undersurface of soft parts of body whitish, with pinkish tinge; dark -marks lacking on soles, present on webbing and palms; dark marks -arranged in linear fashion coincident with digits. - -_Range._--Southern Oklahoma, eastern Texas, extreme southwestern -Arkansas, and the western half of Louisiana; Red River drainage and -rivers that drain into the Gulf of Mexico east of the Brazos River -drainage in Texas and west of the Atchafalaya River drainage in -Louisiana. The Brazos River drainage is inhabited by a population that -more closely resembles _pallidus_ than _guadalupensis_ (see comments -under subsection entitled "Remarks"; see map, Fig. 19). - -_Diagnosis._--Juvenal pattern of white dots that are usually absent or -inconspicuous, but sometimes distinct and small, on anterior third of -carapace, and not surrounded with dark ocelli; white dots often absent -on posterior half of carapace of hatchlings; white spots, rarely as -large as two millimeters in diameter, not encircled with black ocelli -on adult males; pale rim of carapace less than four times wider -posteriorly than laterally. - -_Description._--Plastral length of smallest hatchling, 3.3 centimeters -(KU 50832); of largest male, 16.0 centimeters (SM 2375); of largest -female, 30.5 centimeters (TU 13213). - -Surface of carapace in hatchlings uniform pale brown or tan; small -white tubercles absent or inconspicuous on anterior half of carapace, -but evident on posterior half of carapace, sometimes well-defined (TU -481), but usually inconspicuous (TU 678, 490); pale rim of carapace -less than four times wider posteriorly than laterally. - -Adult males resembling description of holotype; small whitish -tubercles or dots rarely two millimeters in diameter on posterior half -of carapace, smaller and usually inconspicuous on anterior half of -carapace (TU 13281, 486); well-defined whitish tubercles occasionally -on anterior half of carapace (KU 40174); white tubercles not -surrounded with black ocelli; pattern of white dots seemingly less -contrasting in _pallidus_ than in _guadalupensis_, owing to pale brown -or tan carapace; small tubercles along anterior edge of carapace -equilateral or conical having sharp tips. - -Large females usually having pale brown carapaces with slightly -contrasting, brownish, mottled and blotched, patterns; white -prominences often evident posteriorly and anteriorly in middle of -carapace and in nuchal region; tubercles along anterior edge of -carapace equilateral or conical in shape. - -Pattern on side of head and snout variable and of no diagnostic value; -postocular stripe uninterrupted having dark borders (UMMZ 92754), or -interrupted having pale segment behind eye (TU 13282); other -variations in pattern shown on TU 10170 and 15818; pale stripes on -snout having dark inner borders that join and form acute angle (TU -381), or lacking dark inner borders and having uninterrupted dark line -connecting anterior margins of orbits (TU 13280); other variations in -pattern on snout shown on TU 1232, 1291 and 15819; specimens -representing illustrations of variation in pattern on snout (Fig. 5 d, -e, f) all from same locality, Lewisville, Lafayette County, Arkansas; -contrasting pattern on side of head of dark marks on pale background; -contrasting pattern of dark marks on dorsal surface of limbs; markings -on hind limbs generally larger than those on forelimbs; small or fine -markings of some specimens reducing contrast in pattern (TU 478, 488); -carapace sometimes having few small blackish dots confined to margin -(CNHM 15474, TU 487, 1253, 13266); ventral surface of plastron and -soft parts of body whitish and usually lacking dark markings; small -blackish marks often occurring on flap of carapace, in region of -bridge, or on chin and throat (TU 399, 469, 475, 472, 13281). - -Ontogenetic variation in PL/HW, mean PL/HW of specimens having -plastral lengths 7.0 centimeters or less, 4.15, and exceeding 7.0 -centimeters, 5.32; ontogenetic variation in CL/CW, mean CL/CW of -specimens having plastral lengths 8.5 centimeters or less, 1.10, and -exceeding 8.5 centimeters, 1.14; mean CL/PCW, 2.12; mean HW/SL, 1.38 -(including subspecies _guadalupensis_); mean CL/PL, 1.36. - -_Variation._--In 1953, I casually glanced at a hatchling softshell -from the Calcasieu River drainage in the private collection of Mr. -Wilfred T. Neill; the specimen was considered by Neill (1951:15) as -"... an intergradient one (with the _hartwegi-spinifer_ population in -the lower Mississippi drainage)." The hatchling does deviate from -"typical" _pallidus_ in having darkish flecks posteriorly on the -carapace. - -I have seen only one adult male (USNM 94457) from the Sabine River -drainage (Orange County, Texas) that shows characteristics of -_guadalupensis_ (white dots on carapace encircled with small black -ocelli); another adult male (USNM 94456) from the same locality -resembles _pallidus_. Those two USNM specimens were mentioned by Neill -(1951:13) as indicating intergradation with "... the mixed -_spinifera-hartwegi-asper_ populations of Louisiana." - -Two adult males (SM 2889, Pl. 40, bottom, left, and TCWC 471, Trinity -River drainage) have blackish ocelli surrounding the white dots on the -posterior part of the carapace; two large females (TU 14402, Pl. 40, -bottom, right, plastral length, 17.5 cm., and TU 14417 plastral -length, 21.3 cm., both from the Trinity River) have contrasting -mottled and blotched patterns with white dots visible on the carapace. -These turtles show alliance with _guadalupensis_. - -Some individuals from the Brazos River drainage have features -suggesting those that are characteristic of _guadalupensis_. -Hatchlings may have large white dots on the anterior half of the -carapace (USNM 55601). Adult males may have dusky ocelli surrounding -the white dots on the carapace (TU 14169, 14559.1, 14559.2). The -whitish dots, rarely as large as two millimeters, are never so large -as in _guadalupensis_ (three mm. in diameter), and are usually smaller -anteriorly than posteriorly; TU 14169 has white dots approximately the -same size (1.2 mm.) on the anterior half as on the posterior half of -the carapace. The tubercles on adult males are equilateral or -subconical, usually having sharp tips (TU 14348, 14559.1, 14559.2); -the tubercles on large females are subconical, resembling the end of a -bullet, and, in both sexes the tubercles are less conical than those -on specimens of _pallidus_ from farther east. - -Three specimens from the Brazos River drainage are particularly -impressive in their alliance with _guadalupensis_. SM 2556, an adult -male, has large white dots that are encircled with black ocelli on the -posterior half of the carapace, but lacks white dots on the anterior -half. TNHC 14068, a hatchling, has small black dots interspersed with -the larger white dots posteriorly. CNHM 46289 has large white spots on -the carapace that are surrounded with two to four black dots; -scattered black dots also intermix with white spots on the surface of -the carapace (less extensive anteriorly). - -Color notes taken from a freshly-killed adult male (KU 47121) from the -Brazos River, seven miles below Whitney Dam, Bosque-Hill county line, -Texas, are: Carapace pale brown or tan bordered by black line, having -pale lemon yellow rim; yellowish-cream spots on carapace faintly -surrounded with black stippling; dorsal surface of soft parts of body -olive having black marks and patches of grayish; webbing on limbs -having golden or yellowish hue, brighter distally; interorbital region -brown; black-bordered, postocular stripe orange-cream; snout and side -of head olive having pale areas of orange-cream; iris cream having -black stripe; yellowish at juncture of dark dorsal and pale ventral -coloration with orangish tinge on forelimbs and head; tail pale brown -or tan, flanked by black borders that suffuse laterally into -lemon-yellow; undersurface whitish, pale yellow on neck, bluish-gray -on throat. - -_Comparisons._--_T. s. pallidus_ most closely resembles _T. s. -guadalupensis_, but can be distinguished from that subspecies in -having small white tubercles, rarely two millimeters in diameter, on a -pale background, that are not surrounded by blackish ocelli, and are -usually absent, or not conspicuous on the anterior third of the -carapace in adult males; also there are usually no conspicuous white -tubercles or dots on the anterior third of the carapace in hatchlings. -Many adult males of _pallidus_ from the Brazos and some from the -Trinity River drainages often have dusky or black ocelli surrounding -the white dots posteriorly on the carapace; males from these river -systems may be distinguished from _guadalupensis_ in having most, if -not all, white dots on the anterior half of the carapace smaller than -those posteriorly, and a pale brown carapace (in life, usually darker -in _guadalupensis_). _T. s. pallidus_ (and _guadalupensis_) is -distinguished from _emoryi_ in lacking a widened pale rim posteriorly, -and in having small white spots on the anterior half of the carapace. -_T. s. pallidus_ resembles _guadalupensis_ and _emoryi_ in having -white spots on the carapace in adult males. _T. s. pallidus_ differs -from _spinifer_, _hartwegi_ and _asper_ in lacking blackish dots or -ocelli that occur in the center of the carapace. _T. s. pallidus_ -resembles _emoryi_ but differs from _guadalupensis_ in lacking black -ocelli surrounding the white spots. _T. s. pallidus_ resembles -_spinifer_, _hartwegi_ and _asper_ but differs from _guadalupensis_ -and _emoryi_ in having tubercles along the anterior edge of the -carapace that are conical having sharp tips in males, and conical in -large females. - -_T. s. pallidus_ resembles _spinifer_ and _hartwegi_ but differs from -the other subspecies in having a narrow head. _T. s. pallidus_ differs -from _emoryi_ but resembles the other subspecies in having a wider -carapace. _T. s. pallidus_ resembles _emoryi_ and _guadalupensis_, and -differs from the other subspecies in having the carapace widest -farther posterior than one-half the length of the carapace. The snout -of _pallidus_ and _guadalupensis_ is shorter than in _spinifer_ and -_hartwegi_, but longer than in _emoryi_. _T. s. pallidus_ differs from -_asper_ but resembles the other subspecies in having a relatively long -plastron. - -_Remarks._--Intergradation of the subspecies _pallidus_ and -_guadalupensis_ is of a clinal nature in which populations -successively show a gradual resemblance to _guadalupensis_ from -western Louisiana and eastern Texas westward to central Texas. Because -the sharpest break in this cline of characters occurs between the -Colorado and Brazos River drainages, the turtles living in the Brazos -River drainage and eastward are referred to _pallidus_, whereas those -in the Colorado River drainage and westward are referred to -_guadalupensis_. For further comments on intergradation between these -two subspecies, see the account of _T. s. guadalupensis_. - -Taylor (1935:217-18) reported on some specimens of _Amyda spinifera_ -that were obtained by Mr. R. E. McEntyre in "... the spring and summer -of 1926, chiefly about Lewisville, Lafayette County (Arkansas)." Of -the catalog numbers listed by Taylor from Lewisville, 58 (KU, -alcoholic) represent _pallidus_. Three, having the same locality data, -have features that are characteristic of _hartwegi_. KU 2944 (one of -three specimens having this catalog number) is a female having a pale, -mottled and blotched carapace approximately one foot in length; there -are remnants of two dark ocelli, and many widely-scattered, -well-defined dark spots near the periphery of the carapace. KU 2963 -(one of three specimens having this catalog number) is an adult male -that has solid, blackish dots on the entire surface of the carapace. -KU 2964 (one of two specimens with this catalog number) is an adult -male that has ocelli approximately five millimeters in diameter on the -carapace (indistinct in center of carapace). - -Lewisville is situated in the drainage basin of the Red River and is -approximately eight miles east of the Red River and 30 miles west of -the westernmost tributary of the Ouachita River drainage. _T. s. -pallidus_ occurs in the Red River drainage; _hartwegi_ occurs in the -Ouachita River drainage. Perhaps there is intergradation between -_pallidus_ and _hartwegi_ in the intervening streams. There is no data -to indicate from which river or stream each specimen obtained by -McEntyre came; one would presume that all specimens came from the Red -River drainage. But this is not certain. Certainly the 47 specimens -designated herein as _pallidus_ came from the Red River drainage. I -suspect that KU 2944, 2963 and 2964 were obtained from tributaries of -the Ouachita River drainage. - -_T. s. pallidus_ intergrades with the _spinifer-hartwegi_ population -where the Red River joins the Mississippi River in the lower -Mississippi Valley in Louisiana. The majority of 13 juvenal specimens -from the Red River near Shaw, Concordia Parish, Louisiana (USNM -99862-69, 99871-75), resemble _pallidus_ in having inconspicuous white -tubercles on a pale brown carapace. The white tubercles are -conspicuous in USNM 99871. Some specimens have a few small dark dots -confined to the margin of the carapace, as do some "variant" -individuals from well within the geographic range of _pallidus_. USNM -99865 is referred to _hartwegi_ because the carapace is covered with -dark ocelli approximately one millimeter in diameter. Some specimens -from farther west in the Red River drainage are referred to -_hartwegi_. One (USNM 100420) of three from Natchitoches Parish, -Louisiana (TU 5763, USNM 100420-21), having blackish dots on the -carapace, is applicable to _hartwegi_. Of two turtles from Grant -Parish, Louisiana (TU 5647, 12735), only 12735 has dark dots and -ocelli (_hartwegi_). One specimen from Rapides Parish, Louisiana (TU -14040), having dark dots on the entire surface of the carapace, is -referred to _hartwegi_. - -Most specimens from the lower Atchafalaya River drainage are referable -to _pallidus_. Eastward, intergradation occurs with the -_spinifer-hartwegi_ population; USNM 100089-90 from Assumption Parish, -near Napoleonville, Louisiana, are referred to _pallidus_. TU 11983, -from Bayou Lafourche, Raceland, La Fourche Parish, and TU 13698.11, -from Bayou Gauche in St. Charles Parish, Louisiana, are juvenal males -that combine the characteristics of _pallidus_ and _hartwegi_; the -carapaces are covered with blackish spots and posteriorly have -distinct whitish dots. The population in the Atchafalaya River more -closely resembles _pallidus_ than it does _hartwegi_ or _spinifer_. In -former times the Atchafalaya River was presumably continuous solely -with the Red River (inhabited by _pallidus_). Now, these two rivers -and the Mississippi River are interconnected in east-central -Louisiana. A large volume of water of the Mississippi drainage is -conveyed to the Gulf of Mexico by the Atchafalaya, and someone has -said that by approximately 1975, unless man interferes, two-thirds to -three-fourths of the total volume of water of the Mississippi River -will be drained by the Atchafalaya. One can expect, therefore, an -increase in the influence of the _hartwegi-spinifer_ population in the -Atchafalaya River drainage. - -_Specimens examined._--Total 270, as follows: ARKANSAS: _Lafayette_: -KU 2930-37, 2939-40, 2942, 2944 (two of three specimens bear this -catalog number), 2945-57, 2958 (2), 2959-61, 2963 (two of three -specimens bear this catalog number), 2964 (one of two specimens bears -this catalog number), 2965-73, 2987-89, 3056, Lewisville. - -LOUISIANA: _Acadia_: USNM 100151-59, Mermentau River. _Assumption_: -USNM 100089-90, Bayou Lafourche, "near" Napoleonville. _Beauregard_: -TU 1231-32, 1253-55, 1291, 13211, 13266, Sabine River, 8 mi. SW -Merryville. _Bienville_: TU 5649-50, Lake Bistineau. _Caddo_: TU 381, -397-99, 469-72, 474-90, 678, 10170, Caddo Lake: TU 15818-19, Cross -Lake. _Calcasieu_: UMMZ 92754, 5 mi. W Iowa. _Cameron_: TU 1122, -Lacassine Wildlife Refuge. _Concordia_: USNM 99862-64, 99866-69, -99871-75, Red River, "near" Shaw. _De Soto_: SM 2374-75, Wallace -Bayou. _Grant_: TU 5647, Lake Iatt. _Iberville_: USNM 83985, 2 mi. E -Mounds; USNM 100239-41, Grand Lake west of White Castle; USNM 100380, -Plaquemine; USNM 100412, 100414-15, 100419, Spanish Lake, "near" St. -Gabriel. _Jefferson Davis_: Calcasieu River drainage, WTN (no number, -see page 524). _Natchitoches_: TU 5763, Bermuda; USNM 100421, "near" -Natchitoches. _Sabine_: TU 13210, 13212-13, 13265, 13280-82, 13303-06, -Sabine River, 8 mi. SW Negreet. _St. Martin_: USNM 100160, Bayou -Chene; USNM 100650, Atchafalaya. _St. Mary_: USNM 100395-97, 100404, -100409-10, Berwick Bay near Morgan City. - -OKLAHOMA: _Atoka_: OU 8966, Rock Creek, 10 mi. E Atoka; OU 8978, McGee -Creek, 7 mi. SW Daisy. _Caddo_: ANSP 100, Washita River, Fort Cobb. -_Choctaw_: OU 27126, Mayhew Creek, 2 mi. NW Boswell. _Comanche_: OU -4130, 4266, 5390, 8333, 12953, 19986, Wichita Mountains Wildlife -Refuge. _Jackson_: OU 13012, 6 mi. E El Dorado. _Kiowa_: CNHM 15474. -_Le Flore_: OU 6791, Kiamichi River, 8 mi. W Arkansas State Line. -_McCurtain_: OU 2149-50, 2152, 2155, 17126-28, 17185, 2 mi. SW -Smithville; USNM 70397, Red River. _Marshall_: KU 40175-76, 50830-31, -50847, OU 27290, 27297, 27562-63, TU 16076 (5), 16175 (6), 16662 (5), -Lake Texoma, 2 mi. E Willis; KU 50832, mouth of Caney Creek, 4 mi. SW -Kingston. _Pushmataha_: OU 2151, 2157; OU 11365, Buffalo Creek, 5 mi. -NW Tuskahoma. - -TEXAS: _Archer_: TU 16174, 16668-69, Lake Diversion. _Bell_: SM -5667-69, Nolan Creek. _Bosque_: KU 47121, 7 mi. below Whitney Dam, -Brazos River. _Brazos_: BCB 4436, 10 mi. E College Station; BCB 4437, -17 mi. S College Station; BCB 4438, 4 mi. N Bryan; KU 50833, 4 mi. W -College Station; SM 2556, TCWC 472, Wickson Lake; TCWC 539, Little -Brazos River; TCWC 4692, 8 mi. NE Bryan; TCWC 5121, 2 mi. S College -Station; TCWC no number. _Clay_: TCWC 7258, 8 mi. NW Ringgold, -Montague County; TU 16667.1, 3 mi. W Byers. _Dallas_: MCZ 3987, "near" -Dallas; ANSP 13243, Dallas. _Donley_: ANSP 13440, S of Clarendon. -_Eastland_: KU 3132, Cisco. _Galveston_: TCWC 7251, Alta Loma. -_Harris_: UMMZ 92753, Little Cypress Creek, 1 mi. N Westfield; USNM -94335-36, "near" Houston. _Harrison_: USNM 95386, 16.5 mi. SE Caddo -Lake. _Hill_: TU 14169, Richland Creek, 0.7 mi. W Mertens. _Leon_: -CNHM 46290, 5 mi. W Marquez; TCWC 8994, 8996, 6 mi. NW Normangee. -_Liberty_: TU 14402, 14417, Trinity River, "near" jct. with Big Creek. -_McLennan_: BCB 4665-66, 6 mi. NNE McGregor; SM no number, 2037, 2452, -2552, 2558, 2560, 2640, 5263, 6533, Lake Waco; SM 0185, Middle Bosque -River; SM 2104, 6732, Upper Bosque River; SM 5072, Bull Hide Creek; UI -2399, 1.5 mi. W China Springs; UMMZ 64063, Waco; USNM 55601. -_Madison_: TCWC 471, 517, Twin Lakes. _Montgomery_: TCWC 540, 3 mi. S -Conroe. _Nacogdoches_: TNHC 14112, Legg Creek, 5 mi. S Douglass. -_Orange_: UMMZ 117060, 3 mi. S Orange; USNM 94456-57, Orange. -_Randall_: TTC 576, Palo Duro Canyon, 15 mi. SE Canyon. _Shackelford_: -TU 14547, Clear Fork Brazos River, Fort Griffin State Park. -_Somervell_: TCWC 8995, TU 14559 (4), Brazos River, 5-6 mi. E Glen -Rose. _Trinity_: SM 2889, Groveton. _Walker_: TNHC 20829, 5 mi. E New -Waverly. _Waller_: TNHC 14068, 2.7 mi. E Brazos River on US 90. -_Williamson_: MCZ 1627 (2); TU 14348, San Gabriel River, 6.5 mi. E -Georgetown. _County unknown_: ANSP 13448, Wichita River; USNM 7640, -Brazos River. - -_Records in the literature._--LOUISIANA: _Cameron_: Sabine Refuge -(Cagle and Chaney, 1950:386). - -OKLAHOMA: _Le Flore_: 6 mi. W Page. _McCurtain_: 14 mi. SE Broken Bow -(Trowbridge, 1937:301). - -TEXAS: _Bosque_: Bosque River, "near" Valley Mills (Strecker, 1928:6). -_Harris_: Addicks (Brown, 1950:250). _Henderson_: Cedar Creek -(Strecker, 1926a:7). _Jefferson_: 12 mi. SW Port Arthur (Guidry, -1953:56). _Liberty_: Daisetta (Brown, _loc. cit._); San Jacinto River -(Strecker, 1915:15). _McLennan_: "near" Crawford (Brown, _loc. cit._). -_Orange_: 1 mi. N Bridge City (Guidry, _loc. cit._). _Tarrant_: -Trinity River, Fort Worth (Stejneger, 1944:66). _Taylor_: Abilene -(KKA). _Tyler_: Colmisneil (Siebenrock, 1909:603). _Walker_: 6 mi. E -Huntsville (TCWC 329, listed in card file). _Wheeler_: 5 mi. N Wheeler -(Brown, _loc cit._). - - -=Trionyx ater= Webb and Legler - -Black Softshell - - _Trionyx ater_ Webb and Legler, Univ. Kansas Sci. Bull., 40:21, - pls. 1 and 2, 1960, April 20. - -_Type._--Holotype, KU 46903, alcoholic female; obtained 16 km. S -Cuatro Ciénegas, Coahuila, México, by John M. Legler (and party), -September 6, 1958. - -_Range._--Basin of Cuatro Ciénegas, central Coahuila, Mexico (see map, -Fig. 22). - -_Diagnosis._--Posterior margin of carapace of some females having fine -corrugations, edge often ragged, and no pale outer margin; septal -ridges reduced in adult males; over-all dorsal coloration (in -preservative) dark, lacking contrasting patterns. - -_Description._--Plastral length of adult male, 9.6 centimeters (KU -46911); of largest female, 18.4 centimeters (KU 46903). - -Adult male: anterior edge of carapace smooth; septal ridges reduced; -pale outer rim, and small, whitish, dots posteriorly on carapace; -surface of carapace slightly gritty or sandpapery posteriorly; snout -broadened; over-all dorsal coloration dark gray or slate; contrasting -pattern on soft parts of body lacking; ventral surface whitish having -few blackish marks posteriorly on undersurface of carapace. - -Females: posterior margin of carapace usually having fine -corrugations; edge of carapace posteriorly often ragged; pale rim of -carapace absent; mottled and blotched pattern not contrasting on -blackish carapace; dorsal surface of soft parts of body dark gray or -slate, lacking contrasting pattern; ventral surface of carapace and -posterior part of plastron usually having many blackish flecks and -markings; tubercles lacking on anterior edge and in center of carapace -posteriorly; septal ridges well developed. - -Medial angle of epiplastron (as observed through overlying skin) bent -at angle of approximately 90 degrees. Other osteological characters -presumably as in _spinifer_. - -Range in length of plastron (cm.) of 11 females (mean follows -extremes); 10.8-18.4, 15.0; proportional measurements of 12 specimens -(including adult male, mean follows extremes): PL/HW, 4.70-5.43, 4.93; -CL/CW, 1.28-1.43, 1.32; CL/PCW, 1.98-2.42, 2.15; HW/SL, 1.22-1.58, -1.37; CL/PL, 1.29-1.44, 1.36; some females (especially KU 46908) have -noticeably elongate carapaces. - -_Variation._--Corrugations best developed on two largest females (KU -46903, 46906), even present on ventral surface of carapace posteriorly -and on dorsal surface of tail; development of corrugations not -ontogenetic phenomenon as posterior margin relatively smooth on KU -46908 (plastral length, 16.0 cm.) but relatively rugose on KU 46909, -which is smaller (plastral length, 13.9 cm.); smallest female (KU -46904) and adult male having posterior margin smooth; smallest female -having indication of pale outer rim and small whitish dots posteriorly -on carapace, and dark, obtusely-angular line, connecting anterior -margins of orbits; blackish marks on ventral surface reduced on KU -46904, 46910, 46912, and UI 43510; UI 43510 (plastral length, 16.3 -cm.) resembles _T. s. emoryi_ in having more contrasting mottled -pattern on carapace and limbs, indication of pale outer rim on -carapace, and dark line connecting anterior margins of orbits; ventral -surface of tail and hind limbs often tinged with red. - -Color notes from life of young female, topotype (KU 53755) are: -mottled carapace dark brown, pale areas buff; dorsal surface of head -mottled, olive-brown, pale areas buff; iris orange-buff; upper and -lower lips yellow-orange; dorsal surface of limbs olive-brown having -yellow to buff suffusion and small blackish marks; pale areas on -webbing yellow; ventral surface whitish having yellow at margin of -carapace, on neck and limbs. - -_Comparisons._--_T. ater_ most closely resembles _T. spinifer_ -(especially the subspecies _emoryi_) in having a gritty or -"sandpapery" carapace (reduced, tubercles more scattered), whitish -dots on posterior third of carapace (small females and adult male) and -a dark line connecting anterior margins of orbits (smallest female). -Prior to acquiring the characteristic darkened, dorsal ground color, -the pattern on the head and limbs seems to be that of _T. s. emoryi_. - -_T. ater_ resembles _T. muticus_ in having reduced septal ridges in -males, a smooth anterior edge of carapace (especially males), and no -enlarged prominences on the anterior edge of the carapace or -posteriorly in the center of the carapace on large females. _T. ater_ -resembles _T. ferox_ in having an over-all dark coloration dorsally -with no contrasting patterns on adults. - -_T. ater_ probably is a small species resembling _T. muticus_ and _T. -spinifer emoryi_. The head is wide in _T. ater_, resembling that of -_T. ferox_, and closely approaching that of _T. spinifer emoryi_ and -_T. s. guadalupensis_. _T. ater_ resembles _T. ferox_ and _T. s. -emoryi_ in having a narrow carapace. _T. ater_ resembles _T. s. -emoryi_, _T. s. guadalupensis_ and _T. s. pallidus_, but differs from -_T. muticus_, _T. ferox_ and the other subspecies of _T. spinifer_ in -having the carapace widest farther posterior than one-half the length -of the carapace. _T. ater_ resembles _T. ferox_ and _T. s. emoryi_ in -shortness of snout. The plastron is short in _T. ater_ and most -closely resembles that of _T. s. pallidus_, _T. s. guadalupensis_, and -_T. s. emoryi_. - -_Remarks._--_T. ater_ is confined to permanent, clear-water ponds in -the basin of Cuatro Ciénegas. The male and 11 females (KU) were taken -at the type locality (a pond known locally as Tío Candido); the other -female (UI 43510) was taken from a pond approximately seven miles -northward (known locally as Anteojo). _T. spinifer emoryi_ also occurs -in the basin of Cuatro Ciénegas. Males and females of _emoryi_ were -collected in the Río Mesquites (Río Salado drainage) that drains the -basin; two adult males of _emoryi_ were taken from the clear-water -ponds--one from the type locality of _ater_ (KU 46907), and the other -(KU 53757) from a pond (known locally as El Mojarral) from which no -_ater_ were obtained. This demonstrated sympatry indicates that the -two kinds are not conspecific. - -However, the nature and frequency of occurrence of characters of _T. -ater_, suggest that it is subspecifically related to _T. spinifer_--in -effect, a darkened race of _T. s. emoryi_. The diagnostic characters -of fine corrugations on the posterior margin of the carapace and -blackish marks on the ventral surface do not occur on every female of -_ater_. Too, the dorsal coloration of living females (dark brown-buff) -is paler than that of preserved specimens (dark gray-slate). -Furthermore, a hatchling (CNHM 47367) recorded from Cuatro Ciénegas, -Anteojo, is not distinguishable from _emoryi_. - -The mention of absence of septal ridges in males of _T. ater_ in the -original description (Webb and Legler, 1960:22) should be amended. The -septal ridges in the only known adult male are reduced; a small, -whitish ridge is present on the medial surface of each nostril, but is -not conspicuous in anterior view. The one adult male of _ater_ is -distinguished from _T. s. emoryi_ principally on the over-all dark, -dorsal coloration with concomitant loss of pattern, the noticeably -broadened snout, and the reduced septal ridges. The last character -mentioned possibly is variable in _ater_ (and in _emoryi_ in this -region) in view of the variation in development of the ridge on four -male _emoryi_ from the basin: well-developed on KU 53757 (Mojarral) -and KU 46907 (Tío Candido); reduced on KU 53752 (Río Mesquites), -resembling development in _ater_; and, reduced on right side only on -KU 53753 (Río Mesquites). - -Presumably, the continued erosive action at the headwaters of the Río -Salado has permitted the invasion of this drainage into the formerly -isolated basin of Cuatro Ciénegas. In the basin, however, I know of no -evidence of a direct aquatic contact between the headwater streams and -the isolated, clear-water, ponds. How _emoryi_ entered the ponds is -unknown. Some of the ponds are tapped by small, man-made, irrigation -canals, but, so far as I know, these are not connected to the river. -The ponds have permanent water and are often separated by several -miles of arid environment. Overland dispersal between waterways is -possible in time of flooding. Local residents tell of the infrequent -sale of softshells in Cuatro Ciénegas, which hints at their dispersal -via the agency of man. The underlying gypsum substrate of the valley -has been subjected to considerable erosion; the ponds observed have -deep holes, and small caverns and grottos. There are conflicting -reports concerning subterranean connections between ponds. Possibly -there are underwater connections between some ponds and the headwater -streams of the Río Mesquites. Whatever the dispersal route for -_emoryi_ into the ponds has been, it is strange that the same route -has not been traversed by _ater_, permitting its occurrence in the Río -Mesquites. - -On the basis of morphological criteria, I suspect that _ater_ and -_emoryi_ are genetically compatible. Possibly there is only sporadic -entrance of _emoryi_ into the ponds inhabited by _ater_, or the -accessible dispersal routes for _emoryi_ have been relatively recent -and there has been insufficient time for genetic adaptation. _T. ater_ -is maintained as a full species because of the occurrence of two -distinct males (KU 46907, _emoryi_, and KU 46911, _ater_) in the same -pond (Tío Candido, the type locality). These two specimens are -contrasted in a photograph accompanying the type description (Webb and -Legler, 1960: Pl. II). The restricted distribution of _ater_, and its -characteristics suggest a relict population derived from a -_ferox_-like ancestor that may be in the process of becoming extinct. - -There are two specimens in the CNHM recorded from Cuatro Ciénegas. One -is a female (CNHM 55661) having a plastral length of 19.0 centimeters, -and no specific locality other than Cuatro Ciénegas. I examined this -specimen before I knew of the existence of _ater_, and noted no -unusual features; I have not re-examined the specimen. It is -considered representative of _emoryi_. The second is a hatchling (CNHM -47367) having a plastral length of 3.2 centimeters, recorded from -Cuatro Ciénegas, Anteojo. The carapace is dark tan having small -whitish dots intermixed with a few indistinct, small, blackish specks -posteriorly. The specimen is indistinguishable from _emoryi_. - -_Specimens examined._--Total 12, as follows: COAHUILA: KU 46903-06, -46908-12, 53755-56, 16 km. S Cuatro Ciénegas; UI 73510, 5.7 mi. W -Cuatro Ciénegas. - -_Records in the literature._--Schmidt and Owens (1944:103) record -_emoryi_ from Cuatro Ciénegas (no museum numbers listed); presumably -their reference is to CNHM 55661. - - -=Trionyx muticus= Lesueur - -Smooth Softshell - -_Range._--United States from extreme western Pennsylvania, southern -Minnesota and South Dakota south to the Gulf of Mexico in Alabama, the -western end of the panhandle of Florida, and the eastern half of Texas -(see map, Fig. 22.) - - [Illustration: FIG. 22. Geographic distribution of _Trionyx ater_ - and _Trionyx muticus_. 1. _T. muticus muticus_. 2. _T. muticus - calvatus_. 3. _T. ater_.] - -_Diagnosis._--Septal ridges absent; anterior edge of carapace smooth, -lacking prominences; juvenal pattern of large dusky spots (sometimes -ocellate), or small dusky (not black), dots and short lines; side of -head usually devoid of markings except for pale, usually -uninterrupted, postocular stripe. - -Size small; head narrow; snout long; ventral surface of supraoccipital -spine broad proximally, lacking median ridge; foramen magnum evenly -rounded, ovoid; opisthotic-exoccipital spur absent; distal part of -opisthotic wing truncate; lateral condyle of articular surface of -quadrate tapered posteriorly, smaller than medial articular surface; -angle of epiplastron obtuse, approximately 100 degrees; callosity on -epiplastron sometimes covering entire surface; bony bridge wide in -relation to length. - -_Description._--Septal ridges absent; external characteristics -variable (see accounts of subspecies); range in length, in -centimeters, of plastron of ten largest specimens of each sex, (mean -follows extremes), males, 11.8-14.0, 12.3; females, 17.7-21.5, 18.9; -ontogenetic variation in PL/HW, mean PL/HW of specimens having -plastral lengths 7.0 centimeters or less, 4.16, ranging from 7.1 to -13.0 centimeters, 5.82, and, exceeding 13.0 centimeters, 7.04; little -ontogenetic variation in CL/CW, mean CL/CW of specimens having -plastral lengths 8.0 centimeters or less, 1.15, and exceeding 8.0 -centimeters, 1.16; mean CL/PCW, 1.97; mean HW/SL, 1.22; mean CL/PL, -1.39. - -Greatest width of skull usually at level of squamosal (79%); foramen -magnum ovoid; opisthotic-exoccipital spur usually absent (97%); distal -part of opisthotic wing truncate, sometimes visible in dorsal view; -lateral condyle of articular surface of quadrate tapered posteriorly, -smaller than medial articular surface; maxillaries not in contact -above premaxillaries; combination of seven neurals, seven pairs of -pleurals, and contact of seventh pair of pleurals (38%), or eight -neurals, seven pairs of pleurals, and separation of seventh pair of -pleurals (41%); angle of epiplastron obtuse, greater than 90 degrees; -callosities well-developed, frequently on preplastra and epiplastron -of adults. - -_Comparisons._--The absence of septal ridges distinguishes _muticus_ -from _ferox_, all subspecies of _spinifer_, and _ater_ (ridges are -reduced in males of _ater_). The smooth anterior edge of the carapace -distinguishes _muticus_ from all other American kinds except _ater_ -and some individuals of _T. s. emoryi_. _T. muticus_ resembles only -_ater_ and _ferox_ in usually lacking a well-defined, contrasting -pattern of blackish marks on the dorsal surface of the limbs. _T. -muticus_ resembles _ferox_ and differs from _spinifer_ and _ater_ in -lacking a gritty or "sandpapery" carapace on adult males. Adult males -of _T. muticus calvatus_ and some individuals of _T. m. muticus_ from -the Colorado River in Texas further resemble _ferox_ in having -postocular stripes with thick black borders. - -_T. muticus_ is the smallest species in North America; the maximum -size of the plastron in adult males is approximately 14.0 centimeters -(16.0 cm. in _spinifer_) and of adult females 21.5 centimeters (31.0 -cm. in _spinifer_). Males and females of _muticus_ are sexually mature -at approximately the same size as some _T. s. emoryi_; also, the great -development of the plastral callosities in _muticus_ corresponds to -that in some _emoryi_. The head is narrower in _muticus_ than in -_ferox_ or _spinifer_. The carapaces of specimens of _muticus_ -exceeding plastral lengths of 8.0 centimeters are wider than those of -_ferox_, _ater_, _T. s. emoryi_ and _T. s. guadalupensis_ of -corresponding size. _T. muticus_ differs from _ater_ and three -subspecies of _spinifer_ (_pallidus_, _guadalupensis_, _emoryi_) in -having the carapace widest at a plane approximately one-half the -length of the carapace. The snout is longer in _muticus_ than in -_ferox_ and _spinifer_. _T. muticus_ differs from _ferox_ but -resembles _spinifer_ in having a relatively short plastron. - -The skulls of _muticus_ differ from those of _ferox_ but resemble -those of _spinifer_ in usually having the skull widest at the level of -the squamosals. Skulls of _muticus_ resemble those of _ferox_ but -differ from those of _spinifer_ in usually lacking a well-developed -opisthotic-exoccipital spur. Skulls of _muticus_ are different from -those of _ferox_ and _spinifer_ in having the 1) ventral surface of -the supraoccipital spine widest proximally, lacking a medial ridge, 2) -foramen magnum ovoid, 3) distal part of opisthotic wing truncate, 4) -lateral condyle of articular surface of quadrate tapered posteriorly, -smaller than medial articular surface, and 5) maxillaries not in -contact above premaxillaries. - -Plastrons of _muticus_ differ from those of _spinifer_ and _ferox_ in -having an obtusely-angled epiplastron, relatively large callosities -in adults, and a wide hyo-hypoplastral bridge (in relation to length). - -_Remarks._--Agassiz (1857:399) regarded Lesueur's _Trionyx muticus_ as -the type species of the genus _Amyda_ and the only species known to -belong to the genus _Amyda_. Stejneger (1944:7, 9, 12) proposed the -generic name _Euamyda_ as a new name for the North American _Amyda -mutica_ as understood by Agassiz. _Euamyda_ was proposed for use only -if Agassiz's understanding was found to be correct. Actually, -Stejneger thought that the Old World and New World kinds concerned -were congeneric, and that the type species of the genus _Amyda_ was -the Old World species _Amyda javanica_ Schweigger (= _Testudo -cartilaginea_ Boddaert). - -If _Trionyx muticus_ Lesueur is considered to be generically distinct -from other soft-shelled turtles, _Euamyda_ Stejneger, 1944, is -available as a generic name with _Trionyx muticus_ Lesueur, 1827, as -the type species (by monotypy). - -_Geographical variation._--_Trionyx muticus_ shows no obvious -character gradients; the variation is mostly discontinuous and unlike -that in _T. spinifer_. On the basis of differences in the juvenal -pattern and pattern on head, _T. muticus_ can be divided into two -subspecies. - - -=Trionyx muticus muticus= Lesueur - -Midland Smooth Softshell - -Plates 45, 46, and 53 - - _Trionyx muticus_ Lesueur, Mém. Mus. Hist. Nat. Paris, 15:263, - pl.7, December, 1827. - - _Trionyx muticus muticus_ Webb, Publ. Mus. Nat. Hist. Univ. Kansas, - 11:520, August 14, 1959. - - _Potamochelys? microcephala_ Gray, Proc. Zool. Soc. London, p. 87, - 1864. - -_Type._--Lectotype, Museum d'Histoire Naturelle, Paris, No. 8813; -dried carapace and plastron; obtained from the Wabash River, New -Harmony, Posey County, Indiana, by C. A. Lesueur in August, 1827 (Pl. -53). - -_Range._--Central United States; in the Mississippi River drainage -from extreme western Pennsylvania, southern Minnesota and South Dakota -south to Tennessee, Louisiana and Oklahoma; streams of the Gulf Coast -drainage from the Mississippi River in Louisiana westward into Texas -including the Colorado River drainage (see map, Fig. 22). - -_Diagnosis._--Juvenal pattern of dusky dots and usually short lines or -bacilliform marks; ill-defined pale stripes on snout usually evident -just in front of eyes; pale postocular stripe lacking thick, black -borders that are approximately one-half width of pale stripe (except -some in the Colorado River drainage of Texas). - -_Description._--Plastral length of smallest hatchling, 2.1 centimeters -(INHS 3458); of largest male, 14.0 centimeters (CNHM 92003); of -largest female, 21.5 centimeters (KU 2308). - -Juvenal pattern of dusky, grayish marks lacking sharp margins, and -usually consisting of both small spots and short streaks or dashes, -the former predominating; short streaks or dashes occasionally lacking -(TU 14375, Pl. 45, bottom, left; UMMZ 92751); markings variable in -number, few and widely spaced, or several and closely approximated -(Pl. 45, top, topotypes); pale rim separated from ground color by -ill-defined, dusky margin; pattern on adult males well-defined -resembling that of hatchlings (TU 16172.1, 16173), scarcely -discernable (TU 13294), or absent (TU 1242); mottled and blotched -pattern on carapace usually contrasting in large females. - -Pale stripes extending forward from eyes usually not more than half -distance to tip of snout; inner borders of pale stripes on snout -usually absent or dusky and indistinct, occasionally blackish (TU -14606); outer borders of pale stripes darker than inner borders, -usually blackish; pale stripes on snout occasionally absent (CNHM -7845, UMMZ 92665, TU 5989, none of these specimens being large -females); pale postocular stripe having narrow, dusky or blackish -borders (especially UMMZ 92751, TU 14436); pale postocular stripe -usually complete, occasionally interrupted having prominent -dark-bordered anterior segment just behind eye (TU 14416); lower -border of postocular stripe usually in contact with dusky postlabial -line; no other markings on side of head; pattern on dorsal surface of -soft parts of body not contrasting, composed of closely approximated -fine markings that are little darker than background, over-all -coloration pale grayish; occasionally, few larger and more contrasting -markings on hind limbs (UMMZ 92751, TU 14436). - -Underparts white, usually lacking markings; occasional dusky markings -on plastral area (UMMZ 110502), dark spots or flecks on undersurface -of carapace (BCB 6043, UMMZ 92666), or markings on throat (UMMZ -95032). - -Surface of carapace smooth in adult males; large females lacking -prominences posteriorly in center of carapace or in nuchal region; -anterior edge of carapace smooth in both sexes, but occasionally -having regularly spaced furrows or wrinkles (Fig. 8g). - -_Variation._--Short dusky lines and streaks seem to be lacking from -the juvenal pattern on the carapace more often in southern populations -(Gulf Coast drainage of Texas) than in northern populations -(Mississippi River drainage). I have seen one female, KU 48229 (Pl. -46, bottom, left), plastral length 14.5 centimeters that retained a -well-defined juvenal pattern, and lacked a mottled and blotched -pattern. - -Color notes from life of 11 turtles, KU 55296-306, (eight adult males, -three immature females) from the Kansas River at Lawrence, Douglas -County, Kansas, are: Buff-yellow rim of carapace, sometimes having -pale orange tinge; dusky, dark brown markings on pale brown or tannish -carapace of males; dark and pale brown mottled and blotched pattern on -carapace of females (smallest specimens having plastral length, 11.0 -cm.), many having orangish or buffy hue; soft parts of body brownish -to olive-green dorsally, many having small, blackish marks on hind -limbs; webbing of limbs yellowish; pale orange, some yellow, laterally -at juncture of dark dorsum and pale ventrum (to a lesser extent on -hind limbs); pale orange in some suffusing onto dorsal surface of soft -parts of body; black-bordered postocular stripes in males having -orangish tinge (pattern somewhat obscured in females); whitish ventral -surface in some having pale orangish tinge here and there; many having -dusky, grayish flecking on plastral area and anterior ventral surface -(most intense on 55306 giving appearance of grayish suffusion). - -I have seen only three specimens from the Colorado River drainage in -Texas. Two of these (UMMZ 92751, TU 14436) are characterized by much -black pigmentation. A contrasting pattern of relatively large black -marks occurs on the dorsal surface of the soft parts of the body, -especially on the hind limbs, and the pale postocular stripes have -thick black borders. UMMZ 92751, having a plastral length of 5.5 -centimeters, has a juvenal pattern of widely-spaced dark dots that -lacks short lines. The other _muticus_ from the Colorado River (CM -3055), a large female 19.0 centimeters in plastral length, has -ill-defined postocular stripes lacking dark borders, although a small -dusky blotch occurs on the right side of the head. - -_Comparisons._--_T. m. muticus_ differs from _T. m. calvatus_ in -having pale stripes on the snout, a juvenal pattern of small dusky -spots (usually lacking ocellate spots) and short lines, and a pale -postocular stripe lacking thick, blackish borders (except in some -turtles from the Colorado River system of Texas). One unique -characteristic of _muticus_ is the short, dusky lines in the juvenal -pattern; these marks, however, are occasionally absent. - -_Remarks._--_Trionyx muticus_ generally has been considered a distinct -species since its description by Lesueur (1827:263-66, Pl. 7); -Wied-Neuwied (1865:53), at least, questioned the identity of -_muticus_, believing it to be based on a secondary sexual difference -of _T. spiniferus_. Lesueur did not designate a type in the -description, and mentioned that he had seen only three specimens (_op. -cit._:264). Stejneger (1944:17-18) discussed two mounted specimens -(Nos. 787 and 788) in the Natural History Museum at Paris, and -mentioned that No. 787 was designated "... as the type on the printed -label (although presumably not done by Lesueur)." Dr. Jean Guibé (_in -litt._ September 24, 1959) informed me that Nos. 787 and 788 are -numbers without value and correspond, respectively, to catalog numbers -8813 and 8814. In addition, the Museum possesses an alcoholic -specimen, No. 564, obtained by Lesueur from the Wabash River, that -seems to have been acquired by the museum after the publication of the -original description. No. 8813 is regarded as a lectotype. - -Gray (1864:87) described the species _microcephalus_ and questionably -included it in the genus _Potamochelys_ Fitzinger, 1843; the locality -was stated as "Sarawak (Wallace)." Gray especially noted the small -elongate head and believed that the acquisition of adult specimens -would prove that it belonged to a new genus. Later, Gray (1869:221) -proposed the generic name _Callinia_ as a new name for _Aspidonectes_ -as understood by Agassiz (1857:403). Gray referred _microcephala_ to -_Callinia_ (_op. cit._:214, 222) and recognized also _Amyda mutica_ -(_op. cit._:212). Baur (1888:1121) remarked that "_Callinia -microcephala_ Gray, of the British Museum, with the locality Sarawak, -is _Amyda mutica_ Les." The species _microcephalus_ has since been -considered a synonym of _Trionyx muticus_. Schmidt (1953:110) -designated the type locality as New Harmony, Indiana. - -Müller (1878:641) listed the species _Trionyx muticus_ from México as -follows: "*b. in Alcohol. Mexico. 1872. [2]." Smith and Taylor -(1950:18, footnote) wrote that the record required confirmation. Webb -and Legler (1960:24) questionably referred this record to the synonomy -of _T. ater_, which resembles _muticus_. _T. muticus_ is not known to -occur in México. According to Dr. Lothar Forcart (_in litt._) of the -Naturhistorische Museum in Basel, Switzerland, only one specimen on -which Müller based his record is extant. My examination of this -specimen reveals that it is a hatchling _T. s. emoryi_, plastral -length 3.5 centimeters, bearing catalog number 1032; there are no -additional data of collection. - -Strecker and Williams (1927:16) mentioned one specimen of _muticus_ -that was obtained at Christoval, Tom Green County, Texas, and I -presume this is the basis for Pope's mention of this species from Tom -Green County, Texas (1949:319). Although I do not doubt that _T. -muticus_ occurs in Tom Green County, this record possibly is based on -_T. spinifer_ because, 1) there are no specimens of _muticus_ in the -Strecker Museum from Tom Green County, but there is one specimen of -_spinifer_ (SM 3282), and in none of Strecker's publications is there -any mention of _spinifer_ from Tom Green County, and 2) Strecker had, -at least once, misidentified the two species; his record of _muticus_ -from Wallace Bayou, Louisiana (Strecker and Frierson, 1926:last page, -no numbers), represents _T. spinifer pallidus_ (SM 2374-75). - -_Specimens examined._--Total 261, as follows: ALABAMA: _County -unknown_: USNM 118167, Wheeler Reservoir, Tennessee River. - -ARKANSAS: _Franklin_: KU 19459-60, Ozark. _Lafayette_: KU 2938, 3057, -Lewisville. _Lawrence_: CNHM 92003, Imboden; CNHM 92005, Powhatan; -USNM 59214, Black River, Black Rock. _Marion_: TU 14606 (2), White -River at Cotter. _Prairie_: KU 1831, 1868, 1870, 1874-76, 1930-31, -1957-63, 2294-302, 2305-06, 2308-09, 2838-41, 3002, White River, -DeVall's Bluff. - -KANSAS: _Barber_: USNM 95185-86, 1 mi. S Lake City. _Doniphan_: KU -1872, 1878, 1964, Doniphan Lake. _Douglas_: KU 2220, 16148, 23230, -40179, 50825-26, 55296-306, Kansas River, Lawrence; KU 45065-66, 1 mi. -N, 1.5 mi. W Lakeview. _Ford_: KU 51516, Ford. _Kearny_: KU 48216, 4 -mi. S, 1.5 mi. W Deerfield. _Marshall_: KU 48228, Blue Rapids. -_Pottawatomie_: KU 48229-33, 48238, 2 mi. E Manhattan, Riley County. -_Reno_: USNM 95260, 6 mi. E Turon. _Riley_: KU 46861, 48234-35, 4 mi. -N Manhattan; KU 48236, 2 mi. NE Randolph. _Sedgwick_: UMMZ 95362, -Wichita. _Shawnee_: UMMZ 95366-67, Topeka. _Sumner_: USNM 95415, 3 mi. -SE Oxford. _Washington_: KU 48237, 8 mi. S Hanover. _Woodson_: KU -45064, 1 mi. E, 2 mi. S Neosho Falls. _County unknown_: USNM 51528. - -ILLINOIS: _Cass_: INHS 2146, Beardstown. _Coles_: INHS 1965-67, 3 mi. -S Charleston. _Jackson_: INHS 5894, 6.5 mi. N Aldridge, Union County; -UMMZ 81570, Mississippi River. _Jasper_: INHS 2412, Rose Hill. -_Jersey_: INHS 2156-58, Grafton. _Mason_: INHS 2147, Cedar Creek. -_Mercer_: INHS 3458, Keithsburg. _Monroe_: INHS 4088, 3 mi. NE -Columbia. _Morgan_: CNHM 6028, INHS 2148, Meredosia. _Pope_: CNHM 2463 -(30), Golconda. _Schuyler_: UI 40-41, Crooked Creek. _Shelby_: INHS -2283, Holliday. _Wabash_: INHS 5228, Mt. Carmel. - -INDIANA: _Daviess_: UMMZ 110234, White River, 1.5 mi. W Elnora. -_Jefferson_: USNM 8337, Madison. _Knox_: UMMZ 111880-81, "near" Decker -Chapel. _Posey_: INHS 7278-80, 7447, TTC 798, Wabash River, 2-2.5 mi. -S New Harmony; UMMZ 110598, 8 mi. NW Mt. Vernon. - -IOWA: _Allamakee_: UMMZ 92657, 1/4 mi. W Victory, Vernon County, -Wisconsin; UMMZ 92658-64, Mississippi River, "near" Lansing. _Boon_: -UMMZ 92665, Des Moines River at Ledge State Park. _Greene_: UMMZ -92666, 3.5 mi. N Scranton. _Muscatine_: USNM 53521, 54733-34, 54742, -60054-56, Fairport. - -LOUISIANA: _Beauregard_: TU 1242, Sabine River, Merryville. _Caddo_: -CNHM 7845, Gayles. _Catahoula_: USNM 113228, Jonesville. _Concordia_: -USNM 99870, Red River, "near" Shaw. _Ouachita_: TU 5989, Monroe. -_Richland_: USNM 100422, Rayville. _Sabine_: TU 13163, 13294, Sabine -River, 8 miles SW Negreet. _St. James_: TU 7543, Vacherie. _St. Mar_: -USNM 100406, Berwick Bay, "near" Morgan City. _Vernon_: KU 41380, -46777, Sabine River NW Burr Ferry. - -MINNESOTA: _Hennepin_: AMNH 4761-62, Fort Snelling. - -MISSISSIPPI: _Washington:_ USNM 92605, Greenville. _County unknown_: -USNM 115939. - -MISSOURI: _Clark_: USNM 59267, 59278, Alexandria. _Daviess_: UMMZ -95505, Grand River, 1 mi. S Jameson. _St. Louis_: SM 2052, St. Louis. -_Wayne_: UMMZ 82823, St. Francis River. - -NEBRASKA: _Webster_: UMMZ 89526, Republican River, 2 mi. E Inavale. - -OKLAHOMA: _Cleveland_: OU 5480-81, 6473, South Canadian River, 4 mi. -SE Norman. _Hughes_: KU 50845, 4 mi. N Atwood. _Kay_: OU 9741, 8 mi. E -Ponca City. _Le Flore_: OU 2148; OU 27390, Poteau River below Wister -Dam. _Love_: OU 27472, Hickory Creek, 9 mi. E Marietta. _Major_: OU -8597, 7 mi. E Orienta. _Marshall_: KU 50827-29, 50848, 50853, OU -27593-94, TU 16077 (4), Lake Texoma, 2 mi. E Willis. _McIntosh_: OU -8993, 4 mi. W Onapa. _Oklahoma_: OU 10137, Lake Oberholser. _Payne_: -UMMZ 89629, Cimarron River, 3 mi. E Ripley; UMMZ 90002, 19 mi. SE -Stillwater. _Pottawatomie_: OU 25176-83, South Canadian River, 5 mi. -SW Shawnee. _Roger Mills_: OU 12472. _Sequoyah_: OU 9006, Illinois -River, 2 mi. NE Gore. _Tulsa_: UMMZ 95032 (4), Arkansas River at -Tulsa. _Woodward_: CNHM 15472-73; OU 8599-600, 5 mi. E, 1 mi. N -Woodward. - -SOUTH DAKOTA: _Yankton_: UMMZ 110499-500, Missouri River at Fort -Randall; UMMZ 110501-02, Missouri River at Yankton. - -TENNESSEE: _Benton_: UMMZ 53198, Trotter's Landing. _Lake_: USNM -102677, Reelfoot Lake. _Obion_: USNM 102910, Reelfoot Lake. - -TEXAS: _Archer_: TU 16173, Lake Diversion. _Baylor_: TU 16172 (2), -Lake Kemp. _Brazos_: TCWC 7250, Bryan. _Clay_: TCWC 7248-49, 7259-61, -8 mi. NW Ringgold, Montague County; TU 16667, 3 mi. W Byers. -_Grayson_: UI 2419, Lake Texoma. _Gregg_: SM 6685, near Gladewater; -USNM 22629, Sabine River, 5 mi. S Longview. _Liberty_: TU 14416, -14375, Trinity River, "near" jct. with Big Creek. _McLennan_: BCB -6030, 6043, SM 2557, 2561, Lake Waco. _Matagorda_: CM 3055, Colorado -River, Bay City. _San Saba_: TU 14436, San Saba River, 11 mi. NNW San -Saba. _Tarrant_: UMMZ 92750, Worth Lake, Fort Worth. _Wharton_: UMMZ -92751, Colorado River, Wharton. - -NO DATA: MCZ 1594 (erroneously recorded from Mobile, Alabama); USNM -029261, 59982. - -_Records in the literature._--ARKANSAS: _Garland_: Hot Springs (Combs -and Hurter _in_ Strecker, 1924:47). _Jefferson_: Pine Bluff. -_Pulaski_: Little Rock. _Sebastian_: Fort Smith (Hurter and Strecker, -1909:21). - -ILLINOIS: _Adams_: Quincy (Garman _in_ Cahn, 1937:179). _Alexander_: -Horseshoe Lake (Cahn, _loc. cit._); Cairo (Garman _in_ Cahn, _loc. -cit._). _Carroll_: 5 mi. S Savanna (Stejneger, 1944:24). _Clay_: -Louisville. _Clinton_: Carlyle. _Crawford_: Robinson (Cahn, _loc. -cit._). _Cumberland_: Embarrass River (Peters, 1942:183). _Fayette_: -Vandalia. _Gallatin_: Shawneetown (Cahn, _loc. cit._). _Hancock_: -between Warsaw and Hamilton (Stejneger, _op. cit._:23). _Jackson_: -Murphysboro. _Jasper_: Newton. _Marion_: Centralia. _Mason_: Havana. -_Massac_: symbol on map. _Menard_: Petersburg. _Peoria_: Peoria. -_Randolph_: Chester (Cahn, _loc. cit._). _Richland_: Olney (Stejneger, -_loc. cit._). _Rock Island_: Rock Island. _St. Clair_: East St. Louis -(Cahn, _loc. cit._). _Union_: (Cagle, 1942a:199). _White_: Carmi. -_Whiteside_: Sterling (Cahn, _loc. cit._). _Woodford_: Mackinaw Creek -(Garman _in_ Cahn, _loc. cit._). - -INDIANA: _Carroll_: "near" Delphi (Agassiz, 1857:400). _Vigo_: Terre -Haute (Blatchley, 1891:22). - -IOWA: _Des Moines_: "near" Burlington (Agassiz, 1857:400). _Dubuque_: -Mississippi River, 8 mi. S Dubuque (Goldsmith, 1945:447). _Lee_: -Keokuk (Stejneger, 1944:23). - -KANSAS: _Barber_: 5 mi. SE Lake City; Salt River, S of Aetna (Burt, -1935:321). _Cowley_: symbols on map (Smith, 1956:157). _Gray_: -Arkansas River, 1 mi. W Cimarron (Clarke, 1956:215). _Leavenworth_: -Missouri River, Fort Leavenworth (Brumwell, 1951:207-08). _McPherson_: -Lindsborg (Breukelman and Smith, 1946:112). _Pratt_: State Fish -Hatchery, "near" Pratt (Taylor, 1933:269). _Trego_: Wakeeney -(Stejneger, 1944:24). - -KENTUCKY: _Fleming_: Fox. _Rowan_: Triplett (Welter and Carr, -1939:130). _County unknown_: Ohio River (Funkhouser, 1925:71). - -LOUISIANA: _De Soto_: Bayou Pierre (Strecker and Frierson, 1926:last -page, no numbers). - -MINNESOTA: _Houston_: Brownsville (Breckenridge, 1944:183). _Winona_: -Homer (Stejneger, 1944:23). - -MISSISSIPPI: _Warren_: Vicksburg (Cook, 1946:185). - -MISSOURI: _Jackson_: Fry's Lake (Anderson, 1942:219). _Jefferson_: -Meramec River (Boyer and Heinze, 1934:199). _County unknown_: Osage -River (Agassiz, 1857:400). - -NEBRASKA: _Franklin_: 1/2 mi. S Franklin; 1 mi. SE Naponee. _Furnas_: -4 mi. E Cambridge. _Lancaster_: Lincoln. _Nemaha_: Peru. _Thayer_: -(Hudson, 1942:102). _Thomas_: (Smith, 1958:36). - -NEW MEXICO: _San Miguel_: Conchos River above Conchos Dam (Shields and -Lindeborg, 1956:120). - -OHIO: _Brown_: mouth White Oak Creek, Higginsport. _Muskingum_: "near" -Gaysport. _Pike_: Scioto River in Camp Creek, Newton and Scioto Twps.; -Pike Lake. _Scioto_: Scioto River in Clay and Rush Twps.; Scioto -River, Portsmouth; Scioto River, 3 mi. N Rushtown. _Tuscarawas_: -Tuscarawas River, 2 mi. below Gnadenhutten; "near" Winfield. -_Washington_: Dam No. 2, Muskingum River, northern edge of Marietta; -Ohio River, 4 mi. SE Marietta (Conant, 1951:156, 264). - -OKLAHOMA: _Alfalfa_: 6.5 mi. NE Ingersoll. _Comanche_: Camp Boulder, -Wichita National Forest (Ortenburger and Freeman, 1930:188). -_McCurtain_: _Pushmataha_: (Ortenburger, 1927:100). - -PENNSYLVANIA: _Allegheny_: Neville Island, Ohio River below Pittsburgh -(Atkinson, 1901:154). _Clarion_: Allegheny River at Foxburg (Netting, -1944:85). - -?SOUTH DAKOTA: _County unknown_: Fort Mackenzie, Missouri River, 6-8 -mi. below Cedar Island (Stejneger, 1944:15). - -TENNESSEE: _Lake_: Mississippi River (Parker, 1948:29). _Pickett_: -Obey River at Eagle Creek Ford (Shoup, Peyton and Gentry, 1941:75). - -WISCONSIN: _Crawford_: _Pepin_: Mississippi River (Breckenridge, -1944:183; Pope and Dickinson, 1928:82). - - -=Trionyx muticus calvatus= Webb - -Gulf Coast Smooth Softshell - -Plate 47 - - _Trionyx muticus calvatus_ Webb, Univ. Kansas Publ. Mus. Nat. - Hist., 11:519, 1 fig., 2 pls., August 14, 1959. - -_Type._--Holotype, UI 31071, hatchling, sex undetermined, alcoholic; -obtained from Pearl River, Roses Bluff, 14 miles northeast Jackson, -Rankin County, Mississippi, by William F. Childers on August 25, 1952. - -_Range._--Southeastern United States from the Florida Parishes of -Louisiana eastward to the western end of the panhandle of Florida; -rivers of the Gulf Coast drainage from the Escambia River drainage, -Florida, westward to Louisiana and Mississippi including the Pearl -River drainage. The eastern extent of geographic range is not known -(see map, Fig. 22). - -_Diagnosis._--Juvenal pattern of large circular spots, often ocellate; -no stripes on dorsal surface of snout; pattern on dorsal surface of -limbs of fine markings, not in contrast with ground color; pale -postocular stripes having thick black borders approximately one half -width of pale stripe on adult males. - -_Description._--Plastral length of smallest hatchling, 3.0 centimeters -(TU 17301); of largest male, 11.8 centimeters (KU 47118); of largest -female, 18.0 centimeters (TU 13473). - -Juvenal pattern of dusky, circular spots, some ocellate, lacking short -lines and streaks; number of spots variable; some spots on carapace of -hatchlings may have maximum diameter of three millimeters (TU 17301); -pale rim of carapace having dusky, ragged, inner border; juvenal -pattern on adult males absent or usually evident, at least posteriorly -(TU 17306.1). - -Dorsal surface of snout lacking pale stripes just in front of eyes; -pale postocular stripe having thick, black borders on adult males, but -narrower, dusky or blackish borders on juveniles and large females; -lower border of postocular stripe usually in contact with dusky -postlabial line; no other markings on side of head; pattern on dorsal -surface of soft parts of body of closely approximated, fine markings -that are not in contrast with ground color, over-all coloration -grayish; occasionally few larger and more contrasting markings, -especially on hind limbs and anteriolateral surface of forelimbs. - -Underparts whitish, lacking markings, occasional black flecks or dusky -marks posteriorly along ventral edge of carapace (TU 17306.3). - -Surface of carapace smooth in adult males; large females lacking -prominences posteriorly in center of carapace or in nuchal region; -anterior edge of carapace smooth in both sexes, but occasionally -having regularly spaced furrows or wrinkles on hatchlings. - -_Comparisons._--_T. m. calvatus_ can be distinguished from _T. m. -muticus_ by the absence of pale stripes on the snout just in front of -the eyes, in having pale postocular stripes that have thick, black -borders on adult males, and in having a juvenal pattern of large, -circular spots that are often ocellate and three millimeters in -diameter (no short lines). - -_Remarks._--I have not seen specimens of _calvatus_ from the -Tombigbee-Alabama river drainage; presumably Cook's record (1946:185) -from Lowndes County, Mississippi, represents this subspecies. - -It is still not certain that _calvatus_ occurs in streams that drain -into Lake Pontchartrain, Louisiana; TU 17236 from the Amite River that -lacks a diagnostic character is questionably referred to _calvatus_ -(Webb, 1959:524). As mentioned previously _T. s. asper_ shows little -evidence of intergradation with _T. spinifer_ in the Mississippi River -drainage; _asper_ is present in streams of the Lake Pontchartrain -drainage. _T. m. calvatus_ presumably shows a corresponding -relationship with _T. m. muticus_ in the Mississippi River drainage. -There are no specimens that indicate intergradation between _calvatus_ -and _muticus_; _calvatus_ is expected in streams that drain into Lake -Pontchartrain, Louisiana. Probably _calvatus_ occurs eastward in the -Apalachicola drainage system. - -_Specimens examined._--Total, 38 as follows: FLORIDA: _Escambia_: KU -47116, 50852, 50854-55, 50835-36, TU 13473, 16682, 17301, 17302 (2), -Escambia River, 2 mi. E, 1 mi. N Century. - -LOUISIANA: _East Baton Rouge_: TU 17236, Amite River, "near" Baton -Rouge. _Washington_: TU 13795, Bogue Chitto River, Enon; TU 17303 (5), -TU 17304 (4), Pearl River, "near" Varnado. _No data_: TU 17305. - -MISSISSIPPI: _Lawrence_: KU 47117-19, TU 16956, USNM 7655, Pearl River -within 4 mi. of Monticello; TU 17306 (4), Pearl River, 9 mi. S -Monticello. _Marion_: USNM 95133-34, Pearl River, Columbia. _Perry_: -MSC uncatalogued (3), 3 mi. SE New Augusta. _Rankin_: UI 31071, Pearl -River, Roses Bluff, 14 mi. NE Jackson. - -_Records in the literature._--MISSISSIPPI: _Forrest_: no data. -_Jones_: Crawford Bridge. _Lowndes_: Columbus, Lake Park (Cook, -1946:185). - - - - -NATURAL HISTORY - - -Habitat - -Most writers who describe the general habitat of soft-shelled turtles -mention large rivers and streams having some current, and large -permanent, quiet bodies of water having soft mud or sand bottoms, but -note the general avoidance of temporary water. The impermanence of water -in the ponds and "charcos" of headwaters of streams may preclude the -presence of softshells from these otherwise suitable habitats. -Seemingly, soft-shelled turtles are not restricted to particular local -situations or microhabitats in a continuous aquatic environment as are -some kinds of fish, which seem to be more or less confined to riffle -areas or deep holes. Certain activities of softshells such as burying -themselves in soft sand in shallow water or seeking crawfish and other -food over a gravel-rock substrate or one that is débris-laden, are best -carried on in different habitats. Repeated observations of turtles that -are probably engaged in a specific activity in a restricted area may -lead to erroneous general conclusions regarding the over-all preference -for a specific habitat. Perhaps this accounts for Conant's statement -(1951:156) that "In the lower portion of the Scioto River [Ohio] it -appears that the present species [_muticus_] is abundant while -_spinifer_ is almost entirely absent." - -Cagle (1954:181) wrote that softshells "inhabit the extreme headwaters -and smaller tributaries." Other statements in the literature indicate -the variety in kinds of habitat. In Louisiana, Beyer (1900:44) -mentioned _spinifer_ as abundant "in all inland waters, preferring, -however, such bayous which have sloping and sandy banks upon which -they are fond of sunning themselves." Viosca (1923:41) reported -soft-shelled turtles as characteristic "of the large silt-bearing -rivers ... such as the Pearl, Amite, Mississippi and Atchafalaya." -Cagle and Chaney (1950:386) wrote that _spinifer_ in Louisiana was -found in greatest abundance in streams having some current, but that -individuals were also common in quiet areas; the habitats recorded -were: False River--a lake of clear water supporting an abundance of -submerged vegetation, the shallow ends having mats of water hyacinth; -Lakes Iatt and Bistineau--cypress swamps having clear or muddy water; -Caddo Lake--a large lake having a light oil film on the surface of the -water, and vegetation toward the shore consisting of cattails, water -lilies and water hyacinths, and along the bank of cypress and willow -trees; Caddo Lake Spillway--muddy with swift current; Sabine -River--swift current, traps set in quieter backwater areas or near -cypress logs in river; Lacassine Refuge--traps set in inlets and coves -of ship channel having vegetation of water hyacinth, alligator grass, -and along bank, saw grass, cypress knees and snags. Stejneger -(1944:59) reported _spinifer_ taken in barrow pits in Mississippi. - -In Southern Illinois, Cagle (1942:160) recorded _spinifer_ in drainage -ditches (normally having several feet of water and a lush growth of -aquatic vegetation) that connect inland swamps to the Mississippi -flood-plain but dry up periodically, and in Elkville Lake, an -artificial lake having much aquatic vegetation in shallow areas (_op. -cit._:157). Myers (1927:339) recorded a _spinifer_ from Indiana from a -"tiny brook." In east-central Illinois P. W. Smith (1947:39) recorded -_spinifer_ in mud-bottomed dredge ditches, lakes, ponds, small streams -and rivers, whereas _muticus_ was found to prefer rivers having clean, -sandy bottoms and was not taken from lakes or small streams. This -restriction in habitat preference of _muticus_ is again emphasized by -Smith and Minton (1957:346) who wrote that in Illinois and Indiana, -_muticus_ "generally avoids lakes and minor streams." Weed (1923:48), -however, recorded _muticus_ (and _spinifer_) from Meredosia Bay, -Illinois, presumably a broad, shallow, muddy ox-bow lake of the -Illinois River. - -In Minnesota, _spinifer_ has been taken from the Mississippi River, -which is described as fairly swift having a fluctuating water level, -sandy islands, mud banks, a bed of pebbles and large boulders, and -abundant crawfish (Breckenridge, 1955:5). In Michigan, Edgren -(1942:180) recorded _spinifer_ from a "very small muck-bottomed lake." -Evans and Roecker (1951:69) recorded _spinifer_ from Long Point, Lake -Ontario, which is a "broad sand spit, straight on the lakeward side -but irregular with wet flats and lagoons on the bayside." - -In Kansas, Brumwell (1951:207-08) found "mostly young [_muticus_] ... -in the old ponds left during flood stages of the Missouri River" ... -and _spinifer_ occasionally ... "in the backwaters where stagnant -ponds had been formed." In southcentral Kansas, Burt (1935:321) -reported _muticus_ from "a sandbar at junction of a small creek and -Medicine River" ... and ... a "shallow sand-bottomed, algae-filled -pasture streamlet." The same author reported _spinifer_ from a -"sand-bottomed prairie streamlet" ... and ... "an alga-filled pool -near a stream." Burt (_loc. cit._) remarked that "No ecological -differences in general habitat and field behavior of _mutica_ and -_spinifer_ are evident in Kansas." Clarke (1958:21) observed -_spinifer_ in Long Creek (Osage County, Kansas), which is a winding -stream, characterized by numerous deep holes alternating with rocky -riffles, and having high and wooded banks, and mostly mud bottom but -occasional rock bottom. - -Marr (1944:490) mentioned a _spinifer_ that was obtained on the bank -of a small, mud-bottomed stream in the Texas panhandle, and Linsdale -and Gressitt (1937:222) recorded _spinifer_ from irrigation canals in -Baja California. - -In southern Florida, _ferox_ occurs in all fresh-water habitats -(Duellman and Schwartz, 1958:272). Carr (1940:107) reported _ferox_ as -widely distributed in streams, lakes, big springs and canals. Judging -from the numbers of turtles, "the larger canals in the Everglades must -represent something like an optimum habitat" (Carr, 1952:417). Wright -and Funkhouser (1915:119) wrote that in the Okefinokee Swamp, _ferox_ -was especially abundant where the water is deep and the bottom soft, -and the species was found wherever there were alligators. Deckert -(1918:31) wrote that young _ferox_ were taken in springs and brooks -near Jacksonville, Florida. Marchand (_in_ Carr, 1952:417-19) observed -_ferox_ while water-goggling in Florida and noted that individuals -buried themselves in deep water in white sand, mud or bubbling -mud-sand springs, sometimes where there was vegetation overhead. -Neill (1951:16) collected _ferox_ in marshes, "prairies," flood-plain -lakes, lagoons, ox-bow lakes, mangrove swamps, rivers, creeks, -calcareous spring runs, man-made lakes and lime sinks. The same author -(_loc. cit._) reported taking _agassizi_ (= _asper_) in large muddy -rivers, clear "blackwater" streams, calcareous spring runs, creeks, -marshes, lagoons, ox-bow lakes, flood-plain lakes, lime sinks, -man-made lakes, and smaller ponds. Crenshaw and Hopkins (1955:16), -however, stated that in the area where _T. ferox_ and _T. spinifer -asper_ overlap, "_asper_ is nearly always an inhabitant of fluviatile -situations whereas _ferox_ is equally closely confined to -non-fluviatile lakes and ponds"; in the region of sympatry, Schwartz -(1956:8) reported _ferox_ from "a moderately fast, blackwater stream -[Combahee River, South Carolina]." - -Carr (1952:417) wrote that _ferox_ is not uncommon near the mouths of -streams in brackish waters, where the tide must occasionally take it -to sea, and cited Conant, who told of an individual found at sea in -Bahaman waters; Carr (1940:25) listed _ferox_ as occasional in the -marine-littoral, mangrove swamps, as did Neill (1951:16). Neill -(1958:26-27) mentioned his observance of _ferox_ at the mouth of the -Pithlachascotee River, Pasco County, Florida, where the water is -sufficiently saline to favor the growth of oysters, and added that -commercial fishermen had told him that these turtles are sometimes -netted with loggerhead sea turtles (_Caretta_) in the Indian River. -Neill (_op. cit._:5-6) also noted the presence of _ferox_ on Meritt -Island, which supports an extensive saltwater herpetofauna, off the -coast of Brevard County, Florida. Löding (1922:47) recorded _spinifer_ -from Fig Island, Mobile County, Alabama, which is probably a marine or -brackish water habitat. Cagle and Chaney (1950:386) obtained one -_spinifer_ in a brackish marsh of the Sabine Wildlife Refuge, -Louisiana; the poor trapping returns here (one _Trionyx_ and one -_Pseudemys_ in 408 trap-hours) suggest that fresh-water species are -not abundant in brackish habitats. Neill (1958:26-27) has summarized -the occurrence of soft-shelled turtles in marine and brackish -habitats. - -My own observations indicate a variety of habitat preferences; the -term "relatively clear" refers to waters in which visibility extends -four to six inches below the surface at night using a head-light. - -Individuals of _spinifer_ have been taken in large, deep rivers having -a moderate to swift current, relatively clear water, mostly sand and -clay bottoms, and emergent débris intermittent along the shoreline; -the banks may be steep and of mud having a sparse growth of herbs -(Black Warrior River, south of Tuscaloosa, Alabama), or of low -extensive, sandy bars and beaches (Escambia River, near Century, -Florida, Pl. 50, Fig. 1). A juvenile _spinifer_ was taken by hand -among rocks in quiet water behind a rocky shoal in the large, -deep-channeled Ocmulgee River (near Hawkinsville, Georgia). Several -individuals of _spinifer_ were seen in the Flint River (near -Bainbridge, Georgia), which had a swift current in a wide, deep -channel, sandy or sand-silt banks, few brush piles along shore and -many oölitic, submergent snags on an otherwise sandy bottom; the water -was exceedingly clear and permitted water-goggling (this habitat has -been obliterated by a dam on the Apalachicola River). A large female -_spinifer_ was taken on a set line from the bottom of one of several -deep holes (approximately seven feet) that were connected by shallow -areas or riffles (near headwaters of Escambia River--Escambia Creek, -Escambia County, Alabama). Two large females of _spinifer_ (one -escaped) were taken on a trotline set in a large, deep, isolated -barrow pit near the Escambia River (near Century, Florida); there was -no aquatic vegetation, the water was slightly turbid, and the -substrate was of a sand-silt or mud. - -In Arkansas, _spinifer_ has been taken in large deep rivers having -relatively clear water, a moderate current, steep banks four to 15 -feet high, and a substrate of mud with few rocks (one taken on -trotline, escaped; Black River, near Black Rock, Lawrence County). Two -_spinifer_ were taken (trotline and hoop-net) from a smaller -(approximately 50 feet wide) turbid river having a swift current, -débris along the shoreline, and mud-gravel banks (Petit Jean Creek, -Yell County). Several _spinifer_ and _muticus_ were taken from the -White River (Marion County) having a sand-gravel or bed rock bottom -and clear water; individuals were collected by hand in shallow water -(approximately 3-1/2 feet deep) as they lay on the bottom in the main -channel where the current was moderate to swift or in a quiet-water -side channel having submergent vegetation. - -Lake Texoma, an impoundment on the Red River, having a fluctuating -water level with no permanent stand of aquatic vegetation, a mud-rock -or sand-silt bottom, and turbid water (Pl. 49, Fig. 1) is a suitable -habitat for _spinifer_ and _muticus_. _T. spinifer_ is found in large -rivers having relatively clear water, moderate currents, emergent logs -and débris, and mud or sand banks (Little River, McCurtain County, -Oklahoma, Pl. 48, Fig. 1), or small, shallow, turbid creeks having -sand-gravel channels of pools connected by riffle areas (Mayhew Creek, -Choctaw County, Oklahoma). - -Three _spinifer_ were taken from the Llano River (near Llano, Texas) -in a period of low water level in hoop-nets set in a large quiet-water -pond about four feet deep and having patches of rushes encroaching -into the water from the shore. The river bed of sand, gravel and large -boulders consisted of narrower, swift-water channels, small pools and -riffles, and large ponds. - -Individuals of _T. s. emoryi_ have been taken in large ponds having -little or no current, turbid, deep water, and clay or sand-gravel -banks (Río Purificación, Padilla, Tamaulipas). Two _emoryi_ were -collected from a large pond (Río Sabinas, near Sabinas, Coahuila), -which was connected to an adjoining one by riffle areas and had little -or no current, relatively clear, greenish water, clay or mud banks, a -sand-gravel bottom, and was flanked by brush and large cypress trees. -A few _emoryi_ were trapped in hoop-nets that were set in the Río -Mesquites, a stream in central Coahuila approximately 20 feet wide and -six feet deep, flanked by dense stands of _Phragmites_, and having a -moderate current, relatively clear, pea-green water and a mud-sand -substrate with some gravel; the stream enlarged in some places to form -quiet-water coves (Pl. 48, Fig. 2). One adult male _emoryi_ was taken -from a crystal-clear, dendritic, pond (El Mojarral, near Cuatro -Ciénegas, Coahuila), having shallow areas averaging about two feet but -several deep holes--in one of these at the west end of the pond the -water was being emitted under pressure from an underwater cavern and -"bubbling" at the surface; the vegetation consisted of scattered -patches of water-lilies and stonewort; the bottom was a soft mud-marl, -and in some places was carpeted with shells of small gastropods. This -habitat corresponds to that of the type locality of _T. ater_ (Pl. 49, -Fig. 2); see description in Webb and Legler (1960:26). The water of -the ponds is warm; at 8 p. m. on July 31, 1959, the temperature of the -water at the type locality of _ater_ was 29° C., and the air was 27° -C. - -An immature female _spinifer_ was taken on a trotline in a swift, -clear, cold-water habitat having mud banks and an abundance of brush -piles (Little Tennessee River, Monroe County, Tennessee). _T. -spinifer_ occurs also in large ox-bow lakes having relatively clear -water, extensive mats of submerged vegetation, a soft mud bottom, and -several emergent stumps and fallen logs (Lake Concordia, Concordia -Parish, Louisiana); alligator grass and cypress trees encroached to -the shoreline. - -Locality data of some individuals of _spinifer_, _hartwegi_, _asper_, -_pallidus_ and _emoryi_ that were examined indicated that turtles were -captured in ponds, bayous, sloughs, lakes, impoundments, rivers and -creeks, indicating habitation of essentially all permanent waters. - -A juvenile of _hartwegi_ was seen by Mr. Wendell L. Minckley on a -gravel bar jutting into a small, shallow creek having a mud-gravel -bottom (Carnahan Creek, Pottawatomie County, Kansas); the impounding -of the Big Blue River by the Turtle Creek Dam will obliterate this -habitat. Mr. J. Knox Jones, Jr. reported seeing a large softshell in a -narrow, shallow, clear sandy creek in Holt County, Nebraska. - -_T. s. emoryi_ occurs in large rivers having generally turbid waters, -a moderate to swift current and mud or sand bottoms such as the Río -Grande; this habitat corresponds to that of large rivers in the -western parts of the range of _T. s. pallidus_ (Red and Washita) and -_T. s. hartwegi_ (Canadian and Cimarron). These last-named rivers, in -periods of low water level, often have shallow, clear, flowing water -in parts of the river bed. _T. s. emoryi_ has also been taken from -small creeks having bottoms of rocks and large boulders (Black River -Village, Eddy County, New Mexico; field notes of Sydney Anderson and -Kenneth Shain, June 12-14, 1958). - -I received a hatchling _T. s. guadalupensis_ that was obtained in a -clear, shallow-water stream (Hondo Creek, Bandera County, Texas, on -April 12, 1958). The larger streams and rivers known to be inhabited -by _guadalupensis_ are generally clear having greenish-tinted waters. -The geographic distribution of _guadalupensis_ indicates that that -subspecies occurs principally in those waters that drain the -limestone-mantled, Edward's Plateau off the Balcones Escarpment; the -headwaters are characterized by clear, calcareous streams having -occasional travertine deposits. It is probably this type of habitat to -which Agassiz's statement (1857:408) of "clear, bold and rocky -streams" refers. - -There are a few specimens whose locality data indicate a tolerance of -brackish-water habitats. An adult male _spinifer_ was obtained at -Delacroix Island, St. Bernard Parish, Louisiana, a locality said to -have exceedingly brackish waters (Dr. George H. Bick, St. Mary's -College, Notre Dame, Indiana); this adult male (TU 16170) is unique in -having a mottled and blotched pattern. Another adult male (_spinifer_, -TU 16071) was obtained in shallow water in Lake Pontchartrain at the -mouth of Tchefuncta Creek; the salinity at the time of capture was -recorded as 1.7 (datum from Dr. Royal D. Suttkus, Tulane University), -indicating only slightly brackish water. Two _spinifer_ (USNM -100409-10) and one _muticus_ (USNM 100406) were taken at Berwick Bay, -near Morgan City, St. Mary's Parish, Louisiana; the waters at this -locality are probably brackish. The tolerance of brackish waters -doubtless facilitates the dispersal of these turtles along coastal -marshes and swamps, and into adjacent drainage systems. The greater -number of records in the literature pertaining to _ferox_ suggest that -this species may be more tolerant of brackish and marine waters than -are _spinifer_ or _muticus_. - -In summary, _T. ferox_ occurs in all fresh-water habitats, but chiefly -in lentic habitats in the northern part of its range where it and _T. s. -asper_ are sympatric. _T. ferox_ possibly is more tolerant of brackish -and marine waters than are the subspecies of _spinifer_ and _muticus_. - -The subspecies of _T. spinifer_ occur in all fresh-water habitats. In -the southern part of the geographic range, which overlaps that of _T. -ferox_, _T. s. asper_ occurs principally in running-water habitats. _T. -s. pallidus_ and _T. s. asper_ are tolerant of brackish-water habitats. -_T. s. guadalupensis_, known at present only from rivers and streams, -occurs principally in river systems that drain the Edward's Plateau of -southcentral Texas. _T. ater_ is confined to crystal-clear ponds in -central Coahuila. - -The subspecies _muticus_ occurs in large rivers and streams throughout -its geographic range, but is known from lakes and impoundments -principally in the southern part of its range (the northernmost record -is from Reelfoot Lake, Obion County, Tennessee); there is only one -record of _muticus_ from a small, shallow, headwater creek (Reno County, -Kansas), and only one from a lentic habitat (Meredosia Bay, Illinois) in -the northern part of its range. _T. muticus calvatus_ is known at -present only from rivers and streams. - -The seemingly greater restriction of _muticus_ to running-water habitats -suggests less vagility than in _spinifer_ (Netting, 1944:86). - -Size and coloration are adaptations to habitat. Soft-shelled turtles of -large size are best adapted to mesic, essentially continuous swampy or -marshy habitats, whereas small size is an adaptation to less continuous, -semi-isolated habitats. A turtle of the maximum size attained by _ferox_ -in the habitat of _emoryi_ would, in a general way, probably be more -conspicuous and exposed to its enemies, both in the aquatic environment -and during overland excursions; perhaps the kind and amount of food -would be insufficient. In any event, small size is correlated with the -more arid habitats of the southwest, and large size with mesic ones in -the southeast. _T. ferox_, the largest species, and the smallest -population of _T. spinifer_ (resembling _muticus_) both occur in the -southernmost part of the range of the genus. This situation does not -support the corollary of Bergmann's Rule, that pertains to some groups -of terrestrial reptiles, in which those subspecies occurring farther -north, or in cooler climates during their season of activity, tend to be -smaller. - -Within the species _spinifer_, the _emoryi_ group of subspecies are -pallid having whitish dots on the carapace and lack extensive black -pigmentation; these features seem to confer protective coloration on the -inhabitants of arid, essentially sandy or muddy habitats having -sluggish, turbid waters, whereas the more contrasting patterns of the -_spinifer_ group of subspecies eastward seem more suited to existence in -clearer, swifter waters. - -The occurrence of the two clines, _spinifer-hartwegi_ and -_pallidus-guadalupensis_, in the species _spinifer_ are notable in that -the former occurs mostly in one large continuous drainage system, that -of the Mississippi, and shows no sharp break in the one character -distinguishing the two subspecies whereas populations composing the -_pallidus-guadalupensis_ cline are separated into several river -drainages, and show a relatively sharp break in several characters at -the Brazos-Colorado river divide. This situation seemingly supports the -thesis that clines are maintained by some sort of parallel gradient in -ecological or geological conditions. It is notable that streams draining -the Edward's Plateau (inhabited by _guadalupensis_) differ in quantity -(more) and quality (especially CO_{3}^{--}, Ca^{++}, and Mg^{++} ions) -of their solutes, and probably pH (higher) from those farther east -(Hubbs, 1957:102). The gross difference in habitats mentioned above -(sandy, turbid, sluggish streams in the west _vs._ clear, swift streams -in the east) may affect the differentiation recognizable in the -_spinifer-hartwegi_ cline. - - -Daily and Seasonal Activity - - -_Diurnal Habits_ - -Softshells bask on débris in the water or on banks close to the water; -basking presumably raises the bodily temperature. In general in the -southeastern and southwestern United States, I have seen softshells -basking only rarely but once saw six at one time close together on logs -in Bowie Creek, Hattiesburg, Mississippi (species undetermined). Surface -(1908:122) saw _spinifer_ in rows on rocks or logs in tributaries of the -Ohio River. Duellman and Schwartz (1958:271-72) stated that _ferox_ -basks on banks or beds of aquatic vegetation. Deckert (1918:31) -mentioned large _ferox_ "sunning in shallow water at edge of pond." -Minton (1944:447) wrote that _muticus_ and _spinifer_ sun on steep mud -banks (Wabash River). Cahn (1937:180) stated that _muticus_ (in -Illinois) basks on banks at the water's edge but seldom on logs, and -suggests that _muticus_ is less prone to leave the water than -_spinifer_. According to Carr (1952:438), _muticus_ never basks on -logs or rocks. In Ohio, Conant (1951:159) mentioned _spinifer_ as -occasionally basking upon a log or rock, or sometimes on steep clay -banks of streams. On banks, quick escape is facilitated by directing the -head toward the water, thus eliminating the time that it would take to -turn around on land (Conant, _loc. cit._; Newman, 1906:129). Evermann -and Clark (1920:593) mentioned _spinifer_ as basking on sandy or grassy -shores, and large boulders. Muller (1921:181) wrote that _muticus_ basks -four to ten feet from the water's edge on gently sloping sand and mud -shores of small islands in the Mississippi River (near Fairport, Iowa). -Muller stated that basking usually occurs in the morning, up until 2 p. -m., and that beaches with a northern exposure were preferred; he -observed 37 turtles within a 50-foot stretch of beach. In captivity, -hatchlings bask on wire-mesh supports. - -I have frequently observed softshells floating at the surface of the -water, a habit previously mentioned by Surface (1908:122) and Pope -(1949:305, 311). Individuals of _Pseudemys_ and, to a lesser extent, -_Graptemys_ also float at the surface; those kinds of turtles and -softshells at least, often appear at the surface of the water, seemingly -as a result of an inquisitiveness, following repeated disturbances that -cause submergence. - -Newman (1906:131) described the active pursuit of food: "They crawl or -swim along the bottom, thrusting their snouts under stones and into -masses of aquatic vegetation, occasionally snapping up a crayfish or -larva that they have succeeded in dislodging. They do not tear up their -food, but swallow it whole, using the forefeet to assist in forcing it -down." Surface (1908:123) suggested that softshells may feed "upon -insects which may be found floating on the water," and I have had -captives take insects from the surface of the water. Carr (1940:107) -also wrote that _ferox_ and numerous gars in the Tamiami Canal, often at -the mouths of the tributary ditches, snap at each other furiously as -floating bits of food are washed in from the Everglades. Another habit -that has been mentioned as an aid in acquiring food (Breckenridge, -1944:186; Conant, 1951:156; Hudson, 1942:101) is burrowing just below -the surface in a soft bottom in shallow water, to ambush passing fish, -or other food. Presumably all kinds of softshells do this in both -shallow and deep water of lakes or rivers having a suitable substrate; -_spinifer_ and _muticus_ have been reported to burrow in shallow waters -(no observations in deep water) by Agassiz (1857:333), Cahn (1937:180, -189), Conant (1951:159) and Weed (1923:48). Marchand (_in_ Carr, -1952:417-19) noted that _ferox_ burrows in deep water, and mentioned -that in areas of bare white sand a group of fish invariably surrounds -them, and one can locate buried softshells by observing these particular -schools of fish. No mention was made of the turtles attempting to catch -the fish. Other associations of soft-shelled turtles and fish have been -described. Kirtland (_in_ DeKay, 1842:7) observed several large bass -that closely followed large numbers of turtles floating at the surface. -Newman (1906:131) reported the observations of fishermen in Lake -Maxinkuckee that large-mouth black bass stay not far away from swimming -softshells; the same author also mentioned the observations of Jacob -Reighard, who suggested that bass may be feeding upon minnows that he -noticed following softshells. Seemingly some sort of commensalistic -relationship exists whereby fish acquire food that is dislodged by -grubbing and scurrying of softshells. Probably food is pursued on -occasion from a buried position, but this habit probably is not executed -specifically for obtaining food. Newman (_op. cit._:129) was of the -opinion that burrowing in shallow water is a habit to facilitate -"warming up." - -Marchand (_loc. cit._) also wrote of other notable underwater -observations on _ferox_ in Florida. He commented on this turtle's -inquisitiveness in deep water and unconcern upon being touched or even -upon being handled to some degree. Calf-deep in soft mud, he noted a -turtle that "emerged from the mud of the bottom, headed up toward shore, -circled, and when about three feet above the bottom dived suddenly and -completely disappeared." Marchand wrote that some areas on the bottom -(Crystal Springs), which are rooted up by the burrowing of softshells, -are bare and soft, and assume a characteristic, easily recognized, -appearance. - -Cahn (1937:180, 189) stated that the burrowing process consists of -"flipping" the loose sand or silt over the back, whereas Conant -(1951:159) described the process as a rapid lateral movement of the -body. My observations of captives agree essentially with Conant's -observations. The initial movement, directed at a slight angle, is -principally with the forelegs although complemented by lateral movements -of the body. When the turtle is approximately half buried, it makes -rapid lateral movements of the body, which completely bury the turtle -and orient its body in a horizontal position. - - -_Behavior and Adaptations_ - -Some characteristics of softshells that are often mentioned in the -literature are: extreme shyness or wariness, ferociousness as captives, -dazzling speed and agility on land and in water, and great dependence on -aquatic environment. Certainly they are wary; and this wariness may -account, in part, for the scarcity of observations of basking, and -statements attesting to their great speed on land. To my mind, their -reported ferociousness and savage disposition as captives is overrated; -of the many softshells that I have collected, only a few attempted to -bite. The extensibility of their long neck does warrant more careful -handling than needs to be employed with other species. Holbrook (_in_ -Hay, 1892:145) even wrote that they "will sometime leap up and give a -loud hiss," and Newman (1906:130) wrote that "they hiss violently and -thrust out the head." Wright and Funkhouser (1915:120) reported a -captive _ferox_ that "could jump forward practically its own length." I -have been bitten by individuals of _Kinosternon_, _Sternothaerus_, -_Pseudemys_ and _Graptemys_, and cannot support the contention that -softshells are more prone to bite than those species, a view shared by -LeConte (_in_ DeKay, 1842:7); many softshells on initial capture will -tend to withdraw the head completely for a short time. Newman (_loc. -cit._) also wrote that recently captured specimens exude a thick, -yellow, semi-fluid resembling yolk of an egg from the inguinal glands; -the substance, however, is odorless but "undoubtedly homologous with the -emission of the inguinal glands of the musk and snapping tortoises." -Perhaps there is a difference in aggressiveness associated with -geographic location, the age of the turtle or individual temperament. - -Smith (1956:159), referring to _muticus_, wrote that they are the best -swimmers of all fresh-water turtles, and perhaps of any turtles. -Corresponding statements of other authors attesting to their speed and -agility (including _spinifer_ and _ferox_) in water and on land are -based principally on the published comments of Muller (1921:181), who -observed that females disturbed while laying eggs "about fifty feet from -water ... covered the distance faster than a man can run." Cahn -(1937:180) also stated that _muticus_ on a "level, unobstructed sand -beach ... can outrun a man," and (_op. cit._:181) can "capture fish with -ease"; Cahn supported the latter statement by relating his observation -of a _muticus_ that captured a small brook trout in a large tank. Smith -(_op. cit._:162) wrote that _spinifer_ is "said to overtake bass." -Doubtless they are good swimmers and they do scurry rapidly on land. - -Published statements relating to the strictly aquatic existence of -softshells especially _muticus_, are based on recognition of "its -drastic adaptations to aquatic existence" (Carr, 1952:428); these -adaptations presumably include pharyngeal respiration and the marked -depression of body form. Pharyngeal respiration was demonstrated for -_muticus_ and _spinifer_ (Gage, 1884; Gage and Gage, 1886), and was -considered the principal type of aquatic respiration (some dermal and -some cloacal) in _Trionyx spinifer asper_ by Dunson (1960). Cloacal -bursae (anal respiration) are lacking in trionychids (Smith and James, -1955:88). Accessory pharyngeal respiration is meaningful in light of the -information furnished by Agassiz (1857:282-83), who found that _Trionyx_ -has a smaller lung capacity (weight of body in ounces/capacity of lungs -in cubic inches = 16.9) than do some other genera (_Pseudemys_, 2.8; -_Testudo_, 2.7; _Terrapene_, 1.1); corresponding values for more aquatic -species were _Chelydra_, 9.3 and _Kinosternon_, 16.0. Cahn (1937:181), -however, wrote that he has demonstrated pharyngeal respiration in -individuals of _Pseudemys_, _Chrysemys_ and _Sternothaerus_, and Allen -and Neill (1950:13) suggested that it occurs in _Macroclemys_. More -conclusive data are required to detect a positive correlation between -small lung capacity, pharyngeal respiration, and degree of restriction -to an aquatic habitat. - -The depressed, soft-margined carapace of softshells has been mentioned -as an adaptation to facilitate burrowing in soft sand or mud, and more -suited for concealment than for speed in aquatic locomotion (Carr, -1952:429; Smith, 1956:162). Nielsen (1951:264-65), commented that in -various lotic invertebrates, dorsoventral flattening of the body was no -commoner than in lentic invertebrates; he wrote that a dorsoventral -flattening is a disadvantage to an animal in a strong current and is an -adaptation "probably ... not to withstand the current directly, but to -avoid it by seeking shelter in narrow crevices." Probably another aid to -concealment, mentioned by Williams and McDowell (1952:272), is the -plastral hinge. - -Concealment of softshells is not enhanced by growths of algae on the -carapace. Proctor (1958:637-38) reported that the common, epizoöphytic -alga of chelonians, _Basicladia_, has never been reported from -_Trionyx_; the same author recorded a large amount of filamentous algae, -principally _Stigeoclonium_, but the algae could be easily wiped from -the turtle, and Vinyard (1955:64) recorded an alga, _Dermatophyton -radians_, attached to the skin of the legs of _Trionyx_. I noted a small -patch of greenish scum growing near the insertion of the neck on a -softshell (_spinifer_ from Lake Texoma); cursory examination by Dr. R. -H. Thompson, disclosed one of the colonial ciliate protozoans -(resembling _Opercularia_) with enmeshed green or blue-green algae. -Evermann and Clark (1920:592) mention a _spinifer_ from Lake -Maxinkuckee, Indiana, having a growth of _Opercularia_, covering the -plastron. - - -_Movement_ - -The reported proclivity of softshells for a strictly aquatic existence -has been over-emphasized; they are no more confined to aquatic habitats -than some chelydrids (including kinosternids). In fact, there is a -general parallel in habits between members of the two families, namely, -a tendency toward a bottom-dwelling existence, and a burrowing habit. -The alligator snapping turtle (_Macroclemys_) is probably the most -aquatic fresh-water turtle in the United States. The common snapping -turtle and some kinosternids are known to migrate overland. Kinosternids -and trionychids bask frequently, and trionychids have been observed -moving overland. Cox (1894:50) reported a _spinifer_ attempting to climb -a narrowly-stepped, 12-foot dam on Mud Creek at Ravenna, Nebraska; the -turtle failed after repeated struggles, once reaching a height four -inches shy of the brim before tumbling back into the water. Duellman and -Schwartz (1958:271) commented that adults of _ferox_ are often seen on -roads bordering canals, and informants have told me verbally of similar -observations. Conant (1930:61) reported an individual of _ferox_ that -was "... walking across the main street in Venice [Sarasota County, -Florida]." Softshells will travel overland in search for suitable -nesting sites; Newman (1906:130) wrote that _spinifer_ will climb "steep -railway embankments with considerable ease, in order to reach a sand pit -some fifty yards from the water." - -From an analysis of species-composition of large reservoirs and lakes -and their adjacent smaller ponds in southern Illinois, Cagle (1942:162) -concluded that softshells "travel overland far less often than do ..." -other species, but that they are "probably the first to move as the -water level falls." On the basis of further observations in the same -region, Cagle (1944:15) wrote that softshells rarely move overland, and -once trapped in a pool of water, they bury themselves and remain there. -He related instances of several individuals having been dug from dried -mud where the last remnants of a water pool had evaporated and he -concluded that the home range is probably confined to one body of water. -That fluctuations in water level affect the movement of softshells is -suggested by Mr. William E. Brode's comment that a commercial fisherman -trapped numerous softshells in the Pearl River, south of Monticello, -Mississippi, in unbaited hoop-nets in late May and June when the water -level was receding after heavy rains. - -The meager data available concerning the aquatic movements of softshells -indicate that individuals wander but little. Breckenridge (1955:6, -table 1) found that among 30 recaptured turtles that had been marked, -the greatest distance traveled was 600 yards over a two-year interval; -after a three-month interval one originally captured 30 miles distant, -moved only 200 yards. The statement of a professional turtle trapper -mentioned by Breckenridge (_loc. cit._) and data previously presented -(see page 436), to the effect that over-trapping results in increasingly -diminished returns, tends to support the idea that there is little -aquatic movement in soft-shelled turtles. - -Breckenridge (_loc. cit._) mentioned methods of marking softshells and -found that notching the edge of the carapace with a leather punch was -satisfactory; the notches healed but were discernible as shallow -sinuses. The same author mentioned a tattooing device (mentioned also by -Cagle, 1939:171), but no turtles so marked were ever recognized as -recovered. Tagging with a radioactive isotope and detection with -suitable instruments should prove applicable to turtles (see Karlstrom, -1957). - - -_Nocturnal Habits_ - -Anderson (1958:212) wrote that hatchlings (_muticus_) leave nests within -the first three hours after sunset, and are active on the surface of the -sand at night. Muller (1921:183) reported hatchlings (_muticus_) leaving -nests at night or early in the morning. Lagler (1954) stated that -_spinifer_ is nocturnal. To my knowledge there are no other published -statements concerning nocturnal activity of soft-shelled turtles. I have -noted them at night on only four different occasions. In two instances -(Clear Fork Brazos River, Texas, and Lake Concordia, Louisiana), the -turtles were resting immediately below the surface of the water on -submerged branches, as one would expect _Pseudemys_ and _Graptemys_ to -do. Another individual was seen swimming near the surface (Ocmulgee -River, 1-1/2 mi. S Jacksonville, Georgia); this observation possibly -represents nocturnal activity, or inquisitiveness owing to the -disturbances caused by the motor of the boat and/or our head lights. A -final observation tends to support the view of nocturnal habits. My -field notes record at least four softshells collected by hand, and a few -other seen in a shallow (approximately four feet deep), quiet, clear -water side channel of the White River (Cotter, Arkansas); the turtles -were seen resting and slowly moving on the bottom or swimming. - - -_Seasonal Occurrence_ - -The length of the season of activity increases with decrease in -latitude. Aquatic species in general have longer periods of activity -than terrestrial species at the same northern temperate latitudes. The -southernmost populations of all species of softshells may be active -throughout the year, assuming temperature to be the limiting factor. - -There are few published statements relative to the length of the annual -period of activity; all records refer to _spinifer_. In Lake -Maxinkuckee, northern Indiana, Newman (1906:128) wrote that individuals -were first seen in early April on the lake shore in a weak condition -with neck and legs extended, and were easily captured. Lesueur -(1827:262) wrote that _spinifer_ in Indiana appears toward the end of -April. Observations of Evermann and Clark (1920:592) in Lake -Maxinkuckee, and Butler (1894:224) in east central Indiana concurred in -finding that of all kinds of turtles there, softshells appeared last in -spring and disappeared first in fall. Evermann and Clark found small -softshells, benumbed or dead, along the shore as early as March 18 and -also late in fall. The earliest observation for large softshells was -April 29, and the latest was September 7; Butler found that these -turtles rarely appear before April 15 and sometimes not until May 1. -Cahn (1937:191) stated that softshells in Illinois hibernate toward the -end of October and emerge in May or the latter part of April; the same -author mentioned that in southern Illinois the species might remain -sluggishly active all winter. In Ohio, Conant (1951:160) wrote that -individuals were collected every month from March to October, and one -was even taken in December, 1929, in northwestern Ohio. Wright (1919:8) -mentioned observing softshells on April 20 and September 20 (presumably -these were the earliest and latest observations of them) in Monroe and -Wayne counties, New York. Blatchley (1891:34) listed dates of early and -late activity as March 19 and December 11 for Vigo County, Indiana. -Webster (1936:22) recorded the earliest and latest dates of collection -of _spinifer_ in central Oklahoma as June 10 and November 8. - -Moore and Rigney (1942:80) found an individual of _muticus_ under six -inches of ice in water about one foot deep on January 31, 1940 (Cimarron -River, Payne County, Oklahoma). - -The published information suggests that the length of the normal annual -period of activity of _spinifer_ in latitudes of about 40° and 43° is -approximately five months, from April into September, depending upon the -weather. There are numerous published statements to the effect that the -period of hibernation is passed under a shallow covering of mud in deep -water. Evermann and Clark (_op. cit._: 593) found a softshell -(presumably in a quiescent state) on September 6 that was "buried up to -its eyes in mud at the edge of Lost Lake." Softshells possibly hibernate -in shallow water or in soft mud flats. Conant (_loc. cit._) found that -captives would not hibernate in a pond in a zoo having a bottom of -leaves. - - -Food Habits - -Previous authors, most of whom allude to published statements preceding -their own, characterize soft-shelled turtles as carnivorous and mention -such food items as crawfish, insects, worms, snails, clams, frogs, -tadpoles, fish, and occasional vegetable matter. Stockwell (1878:403) -wrote that the relative lengths of portions of the digestive tract -indicate "a purely carnivorous diet." - -In an examination of the contents of 11 stomachs of _spinifer_ from -Michigan, Lagler (1943:304) found that crawfish (47%) and insects -(52%), principally burrowing mayfly naiads (_Hexagenia_), and -dragonfly naiads, comprised the bulk of the diet with cryptogams, -vegetable débris, snails and fish remains present in small amounts. -Breckenridge (1944:186) wrote that 18 specimens of _spinifer_ in -Minnesota contained 44 per cent crawfish, 29 per cent aquatic insects, -8 per cent fish, and 19 per cent unidentified material. Surface -(1908:123) found crawfish in the only two stomachs of specimens he -examined from Pennsylvania. Penn (1950) summarized the results of -those authors, and estimated that crawfishes comprised 58 per cent -(46% by volume) of the diet of softshells. In Indiana, three stomachs -examined by Newman (1906:131) in late June contained: 1) nine -crawfish, 2) four crawfish, 22 dragonfly naiads, 3) nine dragonfly -naiads, few plant buds. Neill (1951a:765) found crawfishes in the -stomachs of five _spinifer_ from the Savannah River, Georgia. Evermann -and Clark (1920:595) wrote that _spinifer_ in Lake Maxinkuckee feeds -principally on crawfishes. Shockley (1949:257) mentioned bottom -organisms and small fishes as food. Clark and Southall (1920:16) -stated that "Its principal food, to judge from a few specimens -examined, consists of crayfishes." - -Cahn (1937:183) wrote that the food of _muticus_ in Illinois consists -principally of crawfish, fish, frogs, tadpoles, larger insect larvae -and nymphs, and aquatic mollusks. The kinds of fish eaten were -_Notropis heterolepis_, _N. spilopterus_, _N. hudsonius_, _Lepomis -machrochirus_, _Morone chrysops_, _Perca flavescens_, _Catostomus -commersonnii_, and _Hypentelium nigricans_; Cahn (_loc. cit._) also -stated that the mollusks eaten by _muticus_ are both gastropods and -small, thin-shelled bivalves. In regard to the feeding habits of -_spinifer_ in Illinois, Cahn (_op. cit._:193) listed the following -items in decreasing order of abundance as revealed by examinations of -stomachs: crawfish, minnows, fry of larger fish, frogs, tadpoles, -earthworms, insects (often beetles), and mollusca (_Pisidium_, -_Viviparus_, planorbids). The kinds of fish mentioned were: _Notropis -heterodon_, _N. heterolepis_, _N. hudsonius_, _Catostomus -commersonnii_, _Lepomis humilis_, _L. macrochirus_, _Semotilus -atromaculatus_, _Notemigonus crysoleucas_, _Umbra limi_, and -_Micropterus salmoides_. Cahn (_loc. cit._) also found the remains of -a six-inch brook trout (_Salvelinus_) in the stomach of a 13-inch -_spinifer_ from Wisconsin. - -Agassiz (1857:399) found larvae of neuropterous insects in the stomach -of one specimen of _muticus_, and fragments of _Anodonta_ and -_Paludina_ (= _Campeloma_) in the stomach of one _ferox_. The expanded -crushing surfaces of the jaws in some large individuals of _ferox_ may -be an adaptation to mollusc-feeding (Schmidt and Inger, 1957:36). -Surface (1908:123) found _spinifer_ to have fragments of beetles in -one of two specimens examined, and large quantities of corn in another -from Ohio. Webb and Legler (1960:27) reported 23 chrysomelid beetle -larvae (_Donacia_) in one specimen of _T. ater_. Evermann and Clark -(1920:595) reported several _spinifer_ taken on hooks baited with -grasshoppers in water 14 feet deep in Lake Maxinkuckee, Indiana. Hay -(1892:144) wrote of _muticus_ that "If there are potatoes growing near -the water the turtles find their way to them and devour the stems, of -which they are very fond." Wright and Funkhouser (1915:123) stated -that young _ferox_ in the Okefinokee Swamp feed on fish and frogs, and -according to the natives, larger specimens take waterfowl, a statement -that Smith (1956:159) was probably reiterating when he mentioned that -the diet included "perhaps young birds." Parker (1939:88) wrote that -of two _spinifer_ from Reelfoot Lake, Tennessee, one contained -coleopteran remains, and the other an aquatic beetle and two large -tipulid larvae. Wied-Neuwied (1865:54) wrote that Lesueur found worms, -snails, remains of _Paludina_ (= _Campeloma_), fruits and even hard -nuts in stomachs of _muticus_. - -Holbrook (_in_ Hay, 1892:145) mentioned that _spinifer_ feeds on fish -and such reptiles as it can secure. There are no published statements -known to me that report reptiles in the diet of American softshells. -Carr (1952:425) erroneously cited Strecker (1927:9) and attributed "a -young lined snake" to the diet of _T. s. emoryi_; Strecker, however, -referred to _Kinosternon flavescens_. In conjunction with raising -softshells on turtle farms, Mitsukuri (1905:261) mentioned that first -and second year-old turtles (_Trionyx sinensis_) must be transferred -to separate ponds or they will be eaten by adults; perhaps -corresponding cannibalistic tendencies exist in confined, natural -habitats in American softshells. - -Captives eat essentially the same things that free-living individuals -do, plus scraps of meat (Strecker, 1927:9; Gloyd, 1928:135; Pope, -1949; Conant, 1951:156, 160). Lagler (1943:303) mentioned a young -_spinifer_ that fed on water fleas (_Daphnia_) and canned fish. Conant -(_op. cit._:160) wrote that no captive was observed to take vegetable -matter. - -Food, mostly in intestines, of two adult females of _T. s. emoryi_ -collected on June 12-14, 1959, from the Río Grande at Lajitas, -Brewster County, Texas, was examined. One female, KU 51961, contained -little food and mostly plant fragments; because the stomach or -intestine was not full of plant fragments, this food probably was -ingested incidentally to the few insects present. Another female, KU -51955, contained insects, which were identified by Dr. George W. -Byers, Department of Entomology, University of Kansas, as follows: 1) -Coleoptera, Dryopidae, genus _Helichus_, most numerous, 350 to 400 -individuals; 2) Coleoptera, Scarabaeidae, genus _Phyllophaga_, one -individual; 3) Odonata, Coenagrionidae, fragments, probably one -individual; 4) Hymenoptera, Sphecidae, subfamily Bembicinae, one -individual; 5) Ephemeroptera; fragments of naiad; and 6) a few plant -seeds, pieces of slender roots, weed stems and a couple of fragments -of tree bark. The scarab and wasp probably fell into the water and -were eaten. - - TABLE 6. Kinds of Insects Found in Stomachs and Intestines of 11 - Specimens of Trionyx m. muticus (Eight Adult Males and Three - Immature Females, 9.0 to 12.5 cm. in Plastral Length) From Douglas - County, Kansas. Frequency of Occurrence (Approximate Number of - Individual Insects/Number of Stomachs in Which Found) Is Given for - Each Item Listed. Fragments of Insects Represent Adults Unless - Otherwise Noted. - - ==========================================================+=========== - FOOD ITEM | Frequency - ----------------------------------------------------------+----------- - Orthoptera | - Locustidae | 1 - | - Ephemeroptera | - Unknown (naiad) | 1 - | - Odonata | - Anisoptera (naiad) | 3/3 - Zygoptera (naiad) | 4/2 - | - Plecoptera | - Unknown (naiad) | 2/1 - | - Homoptera | - Cicadellidae | 20/7 - | - Hemiptera | - Lygaeidae | 1 - | - Neuroptera | - Corydalidae (_Corydalis_ larva) | 1 - | - Trichoptera | - Hydropsychidae? (incl. 18 larvae and 4 pupae) | 23/9 - Unknown (incl. 1 larva) | 4/4 - | - Lepidoptera | - Noctuidae? (larvae) | 2/1 - Pyralidoidea (larva) | 1 - Unknown | 1 - | - Coleoptera | - Carabidae (incl. 1 larva) | 3/3 - Cerambycidae? | 1 - Chrysomelidae | 1 - Cicindelidae (larva) | 1 - Elateridae (larva) | 1 - Hydrophilidae? (larvae) | 4/2 - Scarabaeidae (incl. _Phyllophaga_) | 9/6 - | - Diptera | - Anthomyiidae | 1 - Asilidae | 1 - Bibionidae (_Bibio_) | 5/2 - Calliphoridae (puparium) | 1 - Empididae | 1 - Mycetophilidae | 1 - Tipulidae (incl. _Tipula bicornis_ and _T. triplex_?) | 9/4 - Unknown (5 muscoid, 3 acalyptrate, and 1 cyclorrhaphous | - types) | 9/4 - | - Hymenoptera | - Apoidea | 1 - Formicidae (incl. _Camponotus_) | 11/4 - Ichneumonidae (one questionable) | 4/3 - Tenthredinidae | 1 - Unknown (small wasps) | 3/2 - ----------------------------------------------------------+----------- - -Food from the digestive tracts of 11 specimens of _T. m. muticus_ from -the Kansas River at Lawrence, Douglas County, Kansas, were examined -(Table 6). The turtles (KU 55296-306, eight adult males and three -immature females, ranging in plastral length from 9.0 to 12.5 cm.) -were collected in June, 1958, by Mr. Robert R. Patterson. All turtles -were caught on hook and line in a period of about four or five hours -at dusk. Patterson frequently fished below the bridge at Lawrence and -observed that heads of softshells were often seen there about dusk and -that the turtles seemed to prefer a rather shallow, quiet-water area -of swirls and eddies for feeding. The stomachs, and to a lesser -degree, the intestines, were nearly full. Some turtles contained plant -fragments, principally elm seeds. The kinds of food in this sample -were also identified by Dr. Byers and were mostly insects, the most -frequent item being trichopterans; many of the insects eaten -undoubtedly fell into the water. The remains of spiders were found in -four stomachs and crawfish fragments in five. - -Stomachs of two adults of _muticus_ from Lake Texoma, Oklahoma, were -opened. The stomach of one (OU 27593) was full of naiads of the -burrowing mayfly _Hexagenia_; that of the other female (OU 27594) -contained exoskeletal remains of crawfish. The two specimens were -drowned in gill nets between the hours of 11 a. m. and 7 p. m., on -July 10, 1954; the intact condition of the mayfly naiads indicated -recent feeding. - -The species of American softshells are mainly carnivorous. The presence -of vegetable matter (mentioned in previous paragraphs) in the digestive -tracts of many specimens and True's statement (1893:152) that -soft-shelled turtles include a variety of vegetable matter in their food -indicates omnivorous habits. Duellman and Schwartz (1958:272) stated -that _ferox_ is omnivorous and Carr (1952:430) made a similar statement -for _spinifer_. The diet seems to be determined by the food supply -available, which may vary seasonally or with adverse conditions such as -flooding; under normal environmental conditions, however, vegetable -matter probably is ingested incidentally to other food. There is no -indication of a preference in food habits according to species and -subspecies. Most of the food seems to be obtained by active foraging -that is triggered primarily by movement of the prey; the sense of smell -is probably secondary. - - -Reproduction - - -_Size of males at Sexual Maturity_ - -Elsewhere (1956:121) I have shown that males of _spinifer_ from Lake -Texoma, Oklahoma, and scattered localities in Texas and Louisiana -are sexually mature when they reach a plastral length of 9.0-10.0 -centimeters. Adult males have distinct, convoluted, non-pigmented vasa -deferentia and elongate testes, the maximal measurements of which are -about 10 by 30 millimeters. Testes of hatchlings are approximately 4.0 -by 0.4 millimeters (TU 13698.12, plastral length 3.2 cm., measured with -ocular micrometer). I am not aware of seasonal changes in size of the -testes. - -In reading the discussion that follows, it is well to remember that -males having the cloaca extending beyond the posterior edge of the -carapace are regarded as sexually mature. As an indication of geographic -variation in _spinifer_, I have listed the measurements of the 10 -smallest males for only those subspecies of which there are numerous -records (Table 7). Corresponding data for _T. muticus muticus_ are also -listed for comparison. - - TABLE 7. Size at Sexual Maturity of the 10 Smallest Males of T. m. - muticus and Selected Subspecies of T. spinifer. The Extremes - Precede the Mean (in Parentheses). - - ========================+======================= - SPECIES AND SUBSPECIES | Plastral length (cm.) - ------------------------+----------------------- - _T. s. spinifer_ | 8.8-10.3 (9.6) - _T. s. hartwegi_ | 9.6-10.5 (10.2) - _T. s. pallidus_ | 9.1-11.2 (10.5) - _T. s. guadalupensis_ | 9.3-10.8 (10.1) - _T. s. emoryi_ | 8.2-9.0 (8.8) - _T. m. muticus_ | 8.2-9.2 (8.7) - ------------------------+----------------------- - -The data indicate that the size at which sexual maturity is attained in -_emoryi_ (about 8.0-9.0 cm.) is less than in any other subspecies of _T. -spinifer_ (about 9.0-10.0 cm.), and, more importantly, corresponds to -that of _T. m. muticus_. Although the mean for _T. s. spinifer_ is -slightly less than in the remaining subspecies, I doubt that there is -any significant difference according to subspecies in the size at which -sexual maturity is attained in the subspecies _spinifer_, _hartwegi_, -_asper_, _pallidus_ and _guadalupensis_. The corresponding size in _T. -m. muticus_ and _T. s. emoryi_ heightens the morphological resemblance -between these forms. The only sexually mature male of _T. ater_, which -morphologically resembles _emoryi_ and _muticus_, is 9.5 centimeters in -plastral length. I do not know the size at which _T. ferox_ attains -sexual maturity. The smallest sexually mature individual examined by me -was 12.0 centimeters; probably _ferox_ attains sexual maturity at a -larger size than _spinifer_ or _muticus_. The relative size of -attainment of sexual maturity in _ferox_, _spinifer_, and _muticus_ -corresponds to the maximum size of the three species; _ferox_ is the -largest species and _muticus_ is the smallest (Table 2). - - -_Size of Females at Sexual Maturity_ - -Breckenridge (1955:6) wrote that the development of the mottled pattern -"undoubtedly indicates a stage in the attainment of sexual maturity"; I -have mentioned (1956:121) that the mottled pattern is apparent on -females before sexual maturity is attained. To my knowledge females have -no external characters which appear at the time of attainment of sexual -maturity. - -Sexually mature individuals of _ferox_ have been described in various -terms: 31-1/4 pounds (Goff and Goff, 1935:156); six pounds, lengths of -carapace 10-1/2 and 13 inches (Hamilton, 1947:209); greatest width of -head 3-1/2 inches (Wright and Funkhouser, 1915:120). A 10-1/2 inch -carapace presumably represents the smallest turtle and corresponds to a -plastron approximately 22.0 centimeters in length. There is no other -information available concerning size at sexual maturity in _T. ferox_. - -There is little published information concerning the size at sexual -maturity in _T. spinifer_. Cahn (1937:193) wrote that _spinifer_ in -Illinois "must attain a carapace length of about 24 centimeters -[plastral length approximately 18.0 cm.] before the females become -sexually mature"; this statement is the basis for Smith's mentioning a -length of 9-1/2 inches (1956:162). Evermann and Clark (1920:595) -recorded the lengths of carapace of some females (presumably all adult) -from Lake Maxinkuckee, Indiana, as 11, 11-3/4, 12-1/2, and 13 inches; -the smallest measurement corresponds to a plastral length of -approximately 21.0 centimeters. - -The data concerning reproduction presented in succeeding paragraphs is -based principally upon examinations of turtles in the TU collections; I -am indebted to Dr. Fred R. Cagle for permission to dissect these -turtles. Females are regarded as sexually mature when they have oviducal -eggs or corpora lutea or ovarian follicles exceeding 15 millimeters -in diameter. Hatchlings of _spinifer_ have ovaries that measure -approximately 6.0 × 0.3 millimeters, and straight oviducts 0.2 -millimeters in width (TU 5988, plastral length 3.5 cm. measured with -ocular micrometer). In the size at which sexual maturity is attained -there seems to be much individual variation as well as geographic -variation. - -Females of _T. s. emoryi_ from the Río Grande in the Big Bend region -of Texas are sexually mature when the plastron is approximately 16.0 -centimeters (16.2 cm., KU 51960), and are the smallest adult females -of _spinifer_ that I have seen; these females are representative of -the population from which the smallest adult males of _spinifer_ are -known and which is unique in showing sexual differences in coloration. -A female (TU 3697), having a plastral length of 16.0 centimeters, -which was obtained in the Río Grande near Eagle Pass, Texas, in -mid-July, is immature; the ovaries are compact having the largest -follicles 2.5 millimeters in diameter, and the oviduct is wrinkled and -convoluted but only six millimeters wide. Of three females of _emoryi_ -from the Pecos River, Terrell County, Texas, having plastrons 17.4, -18.3 and 18.8 centimeters in length and obtained on June 11, the -largest and smallest are immature, and internally resemble TU 3697. TU -14453.2 (18.3 cm.) is sexually mature having large corpora lutea and -enlarged ovarian follicles. KU 53754, from the Río Salado in central -Coahuila, México, having corpora lutea and a plastral length of 20.3 -centimeters, is sexually mature. - -Females of _T. s. guadalupensis_, measuring 14.5, 15.7, 16.3, 16.5, -16.8, 17.0, 19.0, and 20.0 centimeters in plastral length and obtained -from June to September, are immature. The female measuring 19.0 -centimeters indicates the approach of sexual maturity in having -swollen and convoluted oviducts seven to ten millimeters in width, but -compact ovaries having the largest follicles 4.0 millimeters. The -other _guadalupensis_ whose measurements are given above have oviducts -that do not exceed four millimeters in width, and ovarian follicles -that do not exceed two millimeters in diameter. TU 10187, obtained in -July, plastral length 19.5 centimeters, is sexually mature having -corpora lutea and enlarged follicles. Two other _guadalupensis_, 21.5 -and 22.0 centimeters (Pl. 12, top), having ovaries with enlarged -ovarian follicles (the largest in one, only 11 mm.) are considered -sexually mature. - -Concerning the subspecies _pallidus_, females (all collected in June -or July) measuring 15.7, 16.3, 17.3, 17.5, 18.7, 19.5, 20.8 and 21.3 -centimeters in plastral length are immature having solid, compact -ovaries with the largest follicles not exceeding two millimeters in -diameter; oviducts are straight not exceeding three millimeters in -greatest width, except those turtles measuring 17.3 and 21.3 -centimeters in which the oviducts are swollen and convoluted and, -respectively, five and eight millimeters in greatest width. The -smallest sexually mature _pallidus_ is 19.8 centimeters in length; -recorded lengths of other adult females are 23.5, 26.8 and 30.5 -centimeters. - -Of especial interest are three large female _pallidus_, measuring -24.8, 27.5, and 28.0 centimeters, which appear to be immature; two of -these (TU 13303-04) are from the Sabine River, collected in July, and -the other specimen is without data (presumably from the Sabine River). -The oviducts are large, swollen and convoluted, resembling those in -sexually mature individuals. The ovaries, however, are relatively -solid and compact having approximate measurements of 125 × 6 -millimeters (TU 13303) and 85 × 10 millimeters (TU 13304), and -follicles not exceeding five millimeters in diameter. - -Females of _spinifer_ from the lower Mississippi Valley of Louisiana -having plastral lengths of 15.0, 15.5, 16.7, 17.5, 18.0, 19.5, 20.0, -20.4, and 20.8 centimeters are considered immature; the ovaries are -compact and solid having follicles not exceeding three millimeters in -diameter, and the oviducts, swollen and convoluted in the larger -individuals, do not exceed six millimeters in width. The ovaries of -the specimen 19.5 centimeters in length mentioned immediately above -had been removed prior to my examination; the oviducts, however, were -relatively straight and only five millimeters in width. Three females -23.0, 25.5, and 25.8 centimeters in length are sexually mature. TU -5518, measuring 21.5 centimeters in length and obtained in June, -indicates the onset of sexual maturity in having large convoluted -oviducts, but the ovaries are solid, compact, measuring 85 × 13 -millimeters, and the largest follicles are only 4.5 millimeters. A -larger turtle (TU 13080), 24.5 centimeters, obtained in July, has -juvenal ovaries (largest follicles five mm.); the oviducts are -enlarged and convoluted as in adult females. - -Of two _T. s. asper_ collected from the Escambia River in June and -July, one 18.0 centimeters in plastral length is immature, whereas the -other, 27.0 centimeters long, is adult. A female _T. s. hartwegi_, -measuring 20.7 centimeters, is adult having enlarged follicles and -corpora lutea (TTC 719, Pl. 36, bottom). - -In summary, females of all subspecies of _spinifer_, except some -_emoryi_, may be sexually mature when the plastron is 18.0 to 20.0 -centimeters in length; probably all physiologically normal females are -adult when 22.0 centimeters long. In general, females are sexually -mature at a plastral length of approximately 20.0 centimeters, a -measurement that corresponds to a length of carapace of approximately -28.0 centimeters or about 11 inches. Females representative of that -population of _emoryi_ inhabiting the Río Conchos and the Río Grande -in the Big Bend region of Texas are adult when the plastron is -approximately 16.0 centimeters in length, and are thus the smallest -sexually mature females of the species _spinifer_. Oviducts are large -(at least eight mm. in width, undistended), swollen and convoluted prior -to the first ovulation. - -Of interest are the large females (for example, TU 13303, plastral -length 28.0 cm.) that seemingly have immature, relatively small, ovaries -(the oviducts are large and convoluted as in adult females). Possibly -such ovaries represent a regression and are in senile turtles, but I am -inclined to believe that the development of these ovaries has been -arrested probably owing to hormonal unbalance, and that they have never -been functional. - -The size of adult females of _T. ater_ is unknown but probably -approximates that of _T. spinifer_ or is slightly less. Females of -_ater_ 15.5 and 17.2 centimeters in length are immature; the largest -female, the holotype, is 18.3 centimeters in length, and was not -dissected. - -Females of _T. muticus_ are sexually mature when smaller than _T. -spinifer_. Two turtles, 13.8 and 14.0 centimeters in length, have large -convoluted oviducts about 10 millimeters in width and ovarian follicles -nine to twelve millimeters in diameter, and seem to be near sexual -maturity. The smallest sexually mature female (subspecies _muticus_) is -TU 14436, measuring 14.4 centimeters in plastral length and having -oviducal eggs. Recorded lengths of other adult females are 16.3, 16.5, -17.2 (subspecies _muticus_), and 18.0 centimeters (subspecies -_calvatus_). Two females having plastral lengths of 17.5 (subspecies -_muticus_) and 16.0 centimeters (subspecies _calvatus_) seem sexually -immature. These turtles collected in April and May have ovarian -follicles not exceeding three millimeters in diameter. - - -_Sexual Activity_ - -Observations by Mitsukuri (1905:263), Conant (1951:160) and Legler -(1955:98), constitute the extent of our knowledge concerning courtship -and copulation. Legler observed a male _spinifer_ and a female _muticus_ -in captivity; the male was the aggressor, following at the rear or above -the female, and at times nipping at the anterior part of her carapace. -During these movements, the posterior edge of the female's carapace was -turned up slightly whereas that of the male was turned down; the turtles -frequently surfaced to breathe. Occasionally the female followed the -male. On the bottom the male crawled onto the female's carapace from the -rear, remaining in a somewhat posterior position as described by Conant -(_loc. cit._), and seemingly not clasping the female with his feet. -Copulation probably occurs in this position; Mitsukuri (_loc. cit._) -mentioned that copulation in _Trionyx sinensis_ occurs at the surface of -the water. The male remains in the coital position for approximately 15 -seconds and then slowly drifts to one side and swims away. Legler -observed five coital unions in one-half hour, each preceded by courting -movements. - -Legler's observations indicate that the courtship patterns of _muticus_ -and _spinifer_ are similar, and that interspecific matings are possible. -I have not noted any hybrid. - -Risley (1933:689) mentioned differential movements of the sexes of -_Sternothaerus odoratus_ in conjunction with the breeding cycle. Such -movements are revealed by trapping procedures that yield deviations from -the expected 1:1 sex ratio. That differential sexual movements probably -occur in _Trionyx_ is indicated by my trapping 17 males in a group of 19 -_spinifer_ in hoop-nets in Lake Texoma in the period June 14-July 12, -1954. On June 24-26, 1959, a field party from the University of Kansas -collected 15 softshells in hoop-nets at the mouth of the Río San Pedro, -near Meoquí, Chihuahua; all turtles were males. On June 17-18, 1959, the -same expedition trapped 11 males in a group of 13 turtles in the Río -Conchos, near Ojinaga, Chihuahua. Earlier, June 12-14, 1959, 39 -softshells were trapped in the Río Grande near Lajitas, Brewster County, -Texas. Of these turtles, however, 19 were adult males and 20 were -females; eight females were adult (sexually mature) all having oviducal -eggs (Fig. 23). One of the two females from Ojinaga, KU 51174, is -sexually mature (plastral length, 16.5 cm.) having oviducal eggs; the -other is immature (plastral length, 8.0 cm.). The only softshell taken -on June 21, 1959, 8 mi. N and 16 mi. W Ojinaga, KU 51173 (plastral -length, 16.3 cm.) is a female having oviducal eggs. The two females from -Lake Texoma are immature (plastral lengths, 9.8 and 12.4 cm.). - -The results of trapping may indicate that females frequent shallow water -for a short time before the period of deposition of eggs, but disperse -to deep water after such periods or between them. The movements of -immature females probably approximate those of adult males; the absence -of immature females in the Meoquí series, and near absence (only one) in -the Ojinaga series perhaps is due to fortuitous collecting methods or to -slightly different diurnal movements between adult males and immature -females. Females approaching sexual maturity and those sexually mature -but not having oviducal eggs ready for deposition possibly remain -relatively sedentary in deep water; such females possibly represent -those absent in the 13.0-15.9 size group (Fig. 23). Certainly, factors -other than those pertaining to egg deposition may cause mature egg-laden -females to live in shallow water, or explain the deviations from the -expected 1:1 ratio. - - [Illustration: FIG. 23. Size distribution of 39 _Trionyx spinifer - emoryi_ (19 males and 20 females) collected in the period June 12 - through June 14, 1959, from the Río Grande, near Lajitas, Brewster - County, Texas. Solid squares represent sexually mature specimens. - Females approaching sexual maturity or those not ready for egg - deposition (13.0-15.9 cm. size group) are possibly sedentary in - deep water.] - -One of the immature softshells (KU 51979, plastral length, 9.7 cm.) of -the series from Lajitas is considered to be a female. It combines -characteristics of both sexes. It resembles a male in having a carapace -gritty to the touch, in having prominent white dots posteriorly and in -not having a faint mottled and blotched pattern as do females of the -same size. The postocular and postlabial markings are mostly yellow -(female), but a small patch of the postocular stripe near the junction -with the pale ventral coloration laterally is tinted with orange (male); -the morphological characters and secondary sexual difference in -coloration of this series of softshells has been mentioned on page 512. -The tail is short and pyramidal resembling that of a female. Internally, -there are a pair of ovaries and oviducts; KU 51979 is functionally a -female. An over-production of androgens probably is responsible for the -external masculine characteristics (orange color, gritty carapace and -absence of mottling on carapace). - - -_Deposition of Eggs_ - -Concerning _T. ferox_, Wright and Funkhouser (1915:122-23) wrote that -deposition of eggs occurred in June and July in the Okefinokee Swamp -on the sandy parts of the islands or in sandy fields in places exposed -to the direct rays of the sun. The same authors recorded a gravid -female taken on June 22 (_op. cit._:120), and a nest with eggs on June -26. Harper (1926:415) reported egg-laying in June in the Okefinokee -Swamp. Goff and Goff (1935:156) found a female in search of a nesting -site crawling toward a cleared area within a hammock at 11 a. m. on -May 19, about 25 yards from the western shore of Lake Griffin, -Florida. Carr (1940:107) stated that eggs in Florida "are laid from -March to July 10. One individual laid her eggs on a block of ice which -we had buried in the sand." Hamilton (1947:209) observed deposition of -eggs near Fort Myers, Florida, in "a sandy roadbed slightly above the -cypress swamp and ditch levels on either side of the road." ... either -in ... "the ruts formed by cars or the slope of the roadbed"; dates of -deposition of eggs recorded are March 30 at 11 a. m. in bright sun, -and March 31 (from context, the date given as March 21 is considered -an error) at 5 p. m. following a heavy rain. The daily temperatures at -the time of Hamilton's observations "averaged 85° F., the first really -warm spell of the season." - -Eigenmann (1896:262) reported egg-laying of _spinifer_ in sand and -gravel in June and July at Turkey Lake (= Lake Wawasee), Indiana. A -turtle was seen digging a nest on June 26, and fresh nests of eggs -were found on June 27 and July 9. Hedrick and Holmes (1956:126) wrote -that a clutch of eggs of _spinifer_ in Minnesota was found about ten -inches deep in sand about one foot from the river; a steep gravel bank -was also cited as a favorite nesting site. Surface (1908:123) stated -that eggs of _spinifer_ in Pennsylvania are laid in May, and the young -hatch in August. Gehlbach and Collette (1959:142) found eggs of -_spinifer_ on June 19 on a sand bank 15 feet from the edge of the -Platte River in Nebraska. Breckenridge (1944:187) wrote that -_spinifer_ in Minnesota nests on sandy beaches from June 14 to July 6. -Cahn (1937:193) stated that deposition of eggs in Illinois occurs in -"June or early July: earlier in the southern part of the state, later -in the northern portion." Force (1930:38) mentioned a gravid female -from Oklahoma obtained on May 20. Evermann and Clark (1920:593) were -of the opinion that _spinifer_ began laying about mid-June and -continued until perhaps late July at Lake Maxinkuckee, Indiana; a -female opened on June 14 had oviducal eggs, and the first nest was -found on June 18. Nests were usually at the edge of an abrupt ascent -in sand; one nest was found in black, mucky soil (_op. cit._:595). -Newman (1906:128) wrote that _spinifer_ in the same lake nests later -than the other species of turtles, as a rule not earlier than the -middle of June (but as early as June 10, _op. cit._:132), and rarely -later than the middle of July; he observed deposition of eggs on June -22. Sites of deposition of eggs were mostly in soft sand not more than -six feet from water; other sites found by Newman (_op. cit._:132-33) -were a sandy, abandoned road bed separated from the shore by a strip -of tall grass, a rock pile (the eggs being dropped into crevices and -sand packed around them), among roots of a tree (the eggs being -deposited between the roots and under them in a very irregular -fashion), and in clay "so hard packed that one could scarcely break it -with the fingers." Natural nest sites in hard clay and a rock pile -seem incongruous with nesting habits of softshells. I note that -Newman's study was not begun until 1902 (_op. cit._:127), and it was -that year that the water level of the lake was high, flooding the -surrounding lowlands (Evermann and Clark, 1920:49-53). Perhaps some of -the nests found by Newman were old and not natural because of -conditions resulting from the receding water level. - -Newman (_op. cit._:134-35) mentioned that in small sandy areas nests -were frequently in contact and overlapped; he found one nest -containing nine small eggs contiguous with 23 large eggs. Breckenridge -(1944:187) reported a nest of 56 eggs of two slightly differing sizes, -and probably from two females. Evermann and Clark (1920:594) -discovered "probably 10 or 12 nests in a distance of a few yards" and -mentioned one nest containing 25 eggs "that evidently belonged to two -different sets ... In the bottom were 10 eggs that looked old ... and -... separated from them by sand, were 15 other eggs." - -Nesting sites of _muticus_ were mentioned by Muller (1921:181) on one -of several small islands having "gently sloping sand and mud shores, -and interior areas of open sand and densely growing willows" in the -Mississippi River, near Fairport, Iowa. The same author wrote that the -egg-laying season is from late June to early July, and that the female -selected a place 10 to 60 feet inland "with an unobstructed view of -the open water." Farther north on the Mississippi River near Dubuque, -Iowa, Goldsmith (1945:447) found that _muticus_ preferred "clean, -somewhat level sandbars and sandy shores free from trash, weeds ... -and exposed to open view." The same species, however, may "make -unsatisfactory nests ... in any place they can find sand, even in the -weeds and bushes ... when the river is high, covering the sandy plots -..." Sometimes nests, which were "seldom nearer than six feet or more -than twenty-five feet from water ...," were submerged by a rise in -water level. In Missouri, Hurter (1911:251) found that individuals of -_muticus_ came "... out on the sandbars in the Mississippi River to -deposit their eggs ... At the end of May up to the middle of June ..." -Cahn (1937:182) wrote that the nesting season of _muticus_ is early -July near Meredosia, Illinois. Anderson (1958:212, Fig. 1) found nests -of _muticus_ along the Pearl River in Louisiana on an open sandbar -(not in gravel, fine sand or silt), whereas nests of _Graptemys_ were -confined to the landward margin of the sandbar. - -The onset and length of the breeding season seems to be geared to the -climatic conditions under which the species occurs, and, as would be -expected, begins earlier and lasts longer in southern latitudes than -in northern latitudes. The period of deposition of eggs in _T. ferox_ -(Florida) is from late March to mid-July, whereas that of northern -populations of _spinifer_ and _muticus_ (southern Great Lakes region) -is usually from mid-June to mid-July. - -Seemingly there is little difference between species in preference of -nesting sites; a sandy substrate is probably preferred. Gravid females -of _ferox_ and _spinifer_ may wander overland some distance and select -places where the view of the water is obstructed by vegetation; both -species may wander little and nest in full view of the water. -Concerning _muticus_, it is of interest that of the many nests -discovered by Anderson (_loc. cit._) on an open sandbar, all were -those of _muticus_ and none was a nest of _spinifer_. The nests of -_muticus_ mentioned by Muller (_loc. cit._) and Goldsmith (_loc. -cit._) were on open sandbars. On June 4, 1953, six clutches of eggs -were found on an open sandbar of the Escambia River, Florida; all -hatchlings from those eggs that were successfully incubated were -_muticus_. On June 1, 1954, three nests were found on an open sandbar -of the same river (Pl. 50); the temperature within the nests at 6:30 -a. m. was approximately 25° C. Two nests were dug in a sand substrate -on the level portion of the bar (Pl. 51, Fig. 1). The third clutch of -eggs was deposited in a sand-gravel substrate at the brim of the -incline from the shore (approximately 30 degrees and about five feet -above the water); the eggs of this clutch were arranged rather -symmetrically (Pl. 51, Fig. 2). Unfortunately, most of the eggs from -these three clutches failed to hatch. Although the data are far from -conclusive, I have the impression that _muticus_ limits its sites of -egg deposition to the open regions of sand bars and does not lay -inland where it must traverse vegetated areas unless preferred nesting -sites are submerged or otherwise unsatisfactory. Females of _spinifer_ -may utilize open sandbars for deposition of eggs but not areas where -_muticus_ occurs. In areas where both _muticus_ and _spinifer_ occur, -the latter probably lays farther inland or on the landward margins of -sandbars. - -Excavation of nests has been observed in _ferox_ (Hamilton, 1947:209), -_muticus_ (Muller, 1921:181-82; Goldsmith, 1945:448), and _spinifer_ -(Newman, 1906:132-33; Cahn, 1937:191-92; Breckenridge, 1960:284). -Turtles leaving the water are cautious, usually stopping and extending -the neck to its greatest length, holding the head high, and sometimes -returning to the water for a short time. Depending on the condition of -the substrate and wariness of the female, nest construction may begin -immediately, or several holes may be dug and then abandoned. The -excavation on level ground or a slight incline is made by means of the -hind feet (Muller mentions digging with the forefeet; I agree with -Pope, 1949:321, and Conant, 1951:264, who consider Muller in error); -the forefeet are firmly planted and not moved during the excavation, -deposition of eggs or the filling of the nest cavity. The hind feet -are used alternately; cloacal water may be used to facilitate digging -or to provide a suitable substrate for the eggs. Cahn mentioned that -some sand may be flung four or five feet, and that during the digging -the head is held high. Breckenridge (_loc. cit._) reported that sand -was thrown a distance of ten feet. The nest may be completed in 16 -minutes (Cahn, _loc. cit._) or less than 40 minutes (Newman, _loc. -cit._). Breckenridge recorded 17 eggs laid in six minutes, Cahn -recorded 12 eggs laid in eight minutes, and Hamilton recorded four -eggs laid in three minutes. The hind feet are used to arrange the eggs -and are used alternately to fill the nest cavity; sometimes a little -sand is scraped in before all the eggs are deposited. Muller recorded -the nest cavity as five inches in diameter and ten inches deep, the -finished nest appearing "as a small crater ... about a foot in -diameter, or where the surface is covered with pebbles, as a circular -area of clear sand." Goldsmith reported that the nest cavity was six -to nine inches in depth, and that after deposition and filling with -sand "By certain twisting movements with all four legs, she drags the -plastron around over the sand, making a perfect camouflage." Newman -found the nest flask-shaped having a depth of about six inches, and -diameters of about three inches at the bottom and one and one-half -inches in the neck. Hamilton described a flask-shaped nest, the -entrance of which would "barely permit the passage of an egg ... the -bottom, at a depth of five inches, being about the width of a quart -milk bottle." Cahn related that the "hole descended at an angle of -about 60°," and the eggs thus rolled down an inclined plane. - -Possibly the nests of _ferox_ and _spinifer_ differ from those of -_muticus_ in being flask-shaped. A nest of _spinifer_ was reported by -Gehlbach and Collette (_loc. cit._) as having a neck three inches -across, a depth of six inches and a width of five inches at the -bottom. The nests of _muticus_ that I discovered on the Escambia River -were not flask-shaped; the eggs were five to seven inches below the -surface. Evermann and Clark (1920:594) reported eggs of _spinifer_ -"generally at a depth of four to ten inches," and Breckenridge (_loc. -cit._) found the topmost eggs about five inches below the surface. -There may be behavioral differences between _ferox_ and _spinifer_ and -_muticus_. Hamilton (_loc. cit._) mentioned that _ferox_ proceeded -with its reproductive duties even when he stood only a few yards away. -Muller (_op. cit._:181) found that _muticus_ would run to the water if -disturbed, without completing deposition of eggs; the same behavior -was described by Cahn (_op. cit._:191) for _spinifer_. Newman -(1906:133) wrote that _spinifer_ will abandon nesting activities if -surprised before egg deposition begins, but will wait to cover the -eggs if interrupted while laying eggs. Goldsmith (1945:448) found that -an observer did not disturb females of _muticus_ when they were laying -eggs (females "could be approached and even touched"), but that, in -the presence of an observer, they would scurry toward the water -without covering the eggs and would not return to cover them. Turtles -frightened in the process of the construction of the nests would not -return to complete the original nest. Harper (1926:415) wrote that -_ferox_, after completing nesting activities, will crawl a few feet -from the nest and scuffle up the surface, presumably to decoy -predators that might otherwise destroy the eggs; this observation has -not been corroborated by other authors. Harper (_op. cit._:416) -recorded the observation of Allen Chesser, who says that females, -after egg deposition, often "... bury themselves, before they go ter -the water, an' stay there ten er twelve hours." - - -_Reproductive Potential_ - -Estimates of reproductive potentials are subject to variation of one -kind or another. Counts of oviducal eggs or those in nests may be -misleading, as in some individuals one or more eggs may have been -deposited previously. Mitsukuri (1905:263), Newman (1906:135), Muller -(1921:182), and Cahn (1937:183) have mentioned that the number of eggs -per clutch corresponds to the size of the female. Females of northern -populations may have larger clutches than females of the same size -from southern populations. - - TABLE 8. Records in the Literature Pertaining to Number and Size - of Eggs of Three American Species of Trionyx. - - ===========+=====================+===================+======================= - | Number of eggs per | | - | clutch; oviducal | Size of eggs; | Authority - SPECIES | (o), nest (n); | ave. = average | and remarks - | ave. = average | | - -----------+---------------------+-------------------+----------------------- - _ferox_ | | 24 mm. | Agassiz (1857, pl. 7, - | | | fig. 20); nat. size. - | | | - | 22 (n) | ave. 31 mm. | Wright and Funkhouser - | | | (1915:120) - | | | - | some (o) | 32 mm. | " - | | | - | 20 (o) | ave. 25 mm., and | Goff and Goff - | | 12 gms. | (1935:156) - | | | - | 17 (o) | ave. 27 mm. | Hamilton (1947:209) - | | | - | 21 (o) | | " - | | | - | 7 (o) | | " (egg - | | | deposition probably - | | | interrupted) - -----------+---------------------+-------------------+----------------------- - _spinifer_ | | 29 mm., 26.5 mm. | Agassiz (1857, pl. 7, - | | | figs. 20 and 23, - | | | respectively); nat. - | | | size. - | | | - | 9, 12, 17, 18, 27 | | Eigenmann (1896:263); - | and 32 | | northern Indiana - | | | - | 9 to 24, ave. 18 | | Newman (1906:135); - | | | northern Indiana - | | | - | about 30 (n), 4 | 1.09 × 1 inch | Evermann and Clark - | (n), 3 (n) | | (1920:593-94); - | | | northern Indiana - | | | - | 21 (n and o) | (o) and some (n) | " - | | .93 × .93 inches; | - | | rest of (n) 1.07 | - | | × 1.07 inches | - | | | - | 32 (o) | ave. 1-1/4 inches | Force (1930:38); - | | | Oklahoma - | | | - | 9, 12, 13, 15, 17, | ave. 28.3 mm. | Cahn (1937:193); - | 19, 19, 21, 22, 23, | (217 eggs) | Illinois - | and 25; ave. 18 | | - | | | - | 12 (o), 26 (o), 24 | 22.0 to 28.5 mm. | Breckenridge - | (n), and 30 (n) | | (1944:187); Minnesota - | | | - | 21 (o) | 24 to 27.8 (ave. | Conant (1951:160); - | | 25.6 mm.) × | Michigan - | | 25.8 to 29 (ave. | - | | 27 mm.) | - | | | - | 22 (n), 22 or | | Hedrick and Holmes - | 23 (n) | | (1956:126); Minnesota - | | | - | 25 (n) | ave. 24 × 25.2 | Gehlbach and Collette - | | mm. | (1959:142); Nebraska - | | | - | 17 (n) | | Breckenridge - | | | (1960:284); Minnesota - -----------+---------------------+-------------------+----------------------- - _muticus_ | | about 22 mm. | Agassiz (1857, pl. 7, - | | | fig. 21); nat. size. - | | | - | 21 | about 20 mm. | Hurter (1911:249); - | | | Missouri - | | | - | 4, 12, 13, 16, 21, | ave. 2.3 cm. and | Muller (1921:182); - | 22, 26, and 33, all | 7 gms. | Iowa - | (n); ave. 22 | | - | | | - | 18 to 22, maximum | ave. 22.6 mm. | Cahn (1937:183); - | 31 | (116 eggs) | Illinois - | | | - | 93 from 5 nests, | variable--largest | Goldsmith (1945:449); - | ave. 18.6; 10, 10, | _ca._ 1-3/8 | Iowa - | 16, 17, 17, 19, 21, | inches, smallest | - | 21, 22, 22, 31, all | less than one | - | (n), ave. 18.7 | inch. | - -----------+---------------------+-------------------+----------------------- - -Additional records of size of clutch are provided by data from dissected -females (Table 9). All females were collected from May through September -from localities south of latitude 36.5°. The number of eggs includes -those in both oviducts, and the number of ovarian follicles those in -both ovaries. The number and range in size of only the largest group of -follicles is listed; in some instances the size of follicles formed a -graded series, and the designation of a group was arbitrary. - - TABLE 9. Length, Number of Oviducal Eggs, and Condition of Ovaries - in Adult Females of T. spinifer and T. muticus. - - ===========+========================+=========+====================== - | | | Ovarian follicles - | | | (total) - SPECIES | Size of female | Eggs +---------+------------ - | (plastral length, cm.) | (total) | | - | | | Number | Size (mm.) - -----------+------------------------+---------+---------+------------ - _muticus_ | 14.4 | 6 | 14 | 15-18 - | 16.3 | 9 | 4 | 15-17 - | 16.5 | | 3 | 16 - | 16.5 | 3 | 4 | 14-18 - | 17.2 | | 13 | 14-21 - | 27.0 | | 25 | 18-21 - -----------+------------------------+---------+---------+------------ - _spinifer_ | 16.2 | 7 | 4 | 16-20 - | 16.2 | 7 | 5 | 18-20 - | 16.2 | 7 | 1 | 18 - | 16.3 | 6 | 5 | 16-18 - | 16.3 | 4 | 5 | 15-19 - | 16.8 | 6 | 1 | 18 - | 17.3 | 3 | 2 | 17 - | 18.3 | | 13 | 19-20 - | 19.5 | | 2 | 17 - | 19.8 | | 4 | 20 - | 20.7 | | 11 | 15-18 - | 21.5 | | 6 | 8-11 - | 22.0 | | 13 | 11-14 - | 23.5 | 8 | 12 | 20-24 - | 25.5 | 11 | several | 18-22 - | 25.8 | 13 | ? | 18-21 - | 26.8 | 10 | 5 | 18-20 - | 30.5 | 13 | 5 | 20-21 - | | 16 | 16 | 16-21 - | | 11 | 19 | 15-20 - | | 17 | 23 | 18-22 - | | 17 | 22 | 14-20 - | | 8 | 15 | 18-22 - -----------+------------------------+---------+---------+------------ - -Published data (Table 8) indicate that the average number of eggs per -clutch for the three American species is about 20, although the number -of eggs may exceed 30 in _spinifer_ and _muticus_. Except for those of -_ferox_, most of these records are based on observations in northern -latitudes (approximately 40°). My examination of females from southern -latitudes (below 36.5°) reveals no oviducal egg count greater than 17 -and an average number of eggs per clutch of 9.6 per _spinifer_ (Table -9); that of _muticus_ is 7.3, as based on data given in Table 9 as -well as on egg-nest counts of 15, 6, 6, 6, 6, 5, 9, 8, and 8. Ovarian -follicles larger than 15 millimeters in diameter are arbitrarily -considered to comprise the next clutch that will be deposited in the -current season. Follicles of this size possibly are retained until the -following year or some may undergo regression; some of the included -follicles may not be representative of the succeeding egg complement. -The average number of follicles of the most enlarged groups is 9.0 for -_spinifer_ and 10.5 for _muticus_. Females in northern latitudes -probably have a greater reproductive potential than those in southern -latitudes if it is assumed that there is only one laying per season -for an individual; the maximum number of eggs laid at any one time -probably does not exceed 35. There is also an indication that larger -females deposit more eggs than smaller females (Table 9). Muller -(1921:184) mentioned two double eggs (each having two yolks) in the -complement of 33, indicating an abnormally large number and excessive -crowding of eggs in the oviducts. Simkins (1925:188) also mentioned -some eggs of a clutch (form and locality unknown) that were five or -six millimeters larger (about 31-32 mm.) than the rest, and which -"invariably bore twins." The largest number of eggs in a single nest -mentioned by Simkins is 22. If the presence of double-yolked eggs is -indicative of crowding of eggs in the oviducts, the egg complements of -22 and 33 indicate the approximate maximal number of eggs per clutch. -In the species _spinifer_, the average size of sexually mature females -is slightly smaller at some places in the south than in the north. -Therefore, smaller clutches are to be expected in the south. - -Many of the females collected in June or July contained corpora lutea -four to eight millimeters in diameter in addition to enlarged ovarian -follicles. Presumably the corpora lutea indicate clutches deposited -earlier in the current season, and the enlarged follicles represent -clutches to be deposited in the current season. One female of -_muticus_ (OU 27593) obtained on July 10, contains oviducal eggs, -ovarian follicles 15-17 millimeters in diameter, and corpora lutea of -different sizes that exceed the number of oviducal eggs; possibly this -female was capable of laying three clutches each season. Corpora -lutea, representing ovulation points of eggs in the oviducts, are -approximately eight millimeters in diameter. In order to establish -definitely the reproductive potentials of any species of turtle, it is -desirable to know the approximate size of ovarian follicles that are -retained by sexually inactive females, and the rate of regression of -the corpora lutea. The data suggest that, in southern populations at -least, two and possibly three clutches of eggs are deposited in the -annual breeding season. Mitsukuri (_in_ Cagle, 1950:38) found that _T. -sinensis_ deposited four groups of eggs each season. - -It is suggested that the seasonal reproductive potential of northern -populations (averaging about 20 eggs per clutch, and probably one -clutch per season) is less than that for southern populations -(averaging about 10 eggs per clutch, but three clutches per season). -But owing to variation, there may be no great discrepancy between the -actual potentials of northern and southern populations. - - -_Eggs_ - -The eggs of _Trionyx_ are white and spherical having a brittle shell. -Some eggs are occasionally abnormal in shape and size; overcrowding of -eggs in the oviducts may result in small, irregular-shaped eggs, or -large double-yolked eggs. Presumably enlargement of the eggs occurs in -the oviducts and within a short period after deposition prior to -complete hardening of the brittle shell; therefore some eggs in the -oviducts are smaller than those in nests. - -The data concerning _ferox_ (Table 8) suggest that the maximum size of -eggs is 31 to 32 millimeters, whereas oviducal eggs are slightly -smaller, about 25 to 27 millimeters. Eggs of _spinifer_ from northern -latitudes (most from approximately 40°, Table 8) also vary in size, -oviducal eggs being as small as 22 millimeters in diameter and the -maximal size about 29 millimeters. Average extreme measurements (in -mm.) of oviducal eggs (number of eggs in parentheses) from females -taken in latitudes of 33 degrees or less are: 25 × 29 (11), 29 × 30 -(11), 28 × 30 (13), 28 × 30 (10), 29 × 30 (5), 29 × 29 (8), 25 × 26 -(17), 29 × 30 (5), and 28 × 29 (8). The average size of these eggs is -slightly larger than the oviducal eggs of which measurements are given -in Table 8, and suggest larger eggs from more southern latitudes. Eggs -of _muticus_ are smaller than those of _spinifer_ (Cahn, 1937:183) or -_ferox_; the average size of eggs from nests found in Iowa and -Illinois is 22 to 23 millimeters (Table 8). Nine oviducal eggs from a -female obtained in Lake Texoma, Oklahoma, averaged 22 × 23 -millimeters. The largest eggs of _muticus_ are from the southernmost -locality; eight eggs from a nest found along the Escambia River, -Florida, averaged 26 × 27 millimeters. - -In general, the data suggest that at each laying slightly smaller eggs -but larger numbers are laid by females in northern latitudes, whereas -larger but fewer eggs are laid by females from farther south. - - -_Incubation and Hatching_ - -Length of the incubation period seems to depend upon conditions of -heat and moisture, and, in general, to be geared to the prevailing -climatic conditions. Goff and Goff (1935:156) artificially incubated -some eggs of _ferox_ at temperatures varying from 82.3 to 89.2° F., -and found that the incubation period was 64 days. Muller (1921:184) -wrote that the period of incubation of eggs of _muticus_ (natural -nests at temperatures about 90°., _op. cit._:182, and artificial -nests) in Iowa is from 70 to 75 days. Breckenridge (1944:187) stated -that _spinifer_ makes nests in Minnesota from June 14 to July 6, and -cited reports that indicate hatching in September. Hedrick and Holmes -(1956:126) discovered a nest of eggs in Minnesota on September 5; the -eggs were artificially incubated and some hatched on October 29. -Eigenmann (1896:263) found eggs as late as September in northern -Indiana that "contained young which would have been ready to hatch -about a month later." Cahn (1937:193) wrote that _spinifer_ in -Illinois lays in June or early July and that "young-of-the-year are -taken in late August and September." Some recently deposited eggs of -_muticus_ (as indicated by fresh turtle tracks, Pl. 50, Fig. 2) that I -obtained on June 1 were artificially incubated and hatched on August -4, indicating an approximate incubation period of 65 days. Dr. Paul K. -Anderson in the course of field work on the Pearl River, Louisiana -(1958:211), found that eggs collected on June 13 from a nest excavated -three to five days before, hatched on August 15, indicating an -incubation period of approximately 67 days. Eggs collected on May 17 -to 25 (three clutches) hatched on August 4 to 6, indicating an -incubation period of approximately 77 days. In any latitude the -incubation period probably is at least 60 days. Eigenmann (_loc. -cit._), however, mentioned empty nests that were found in July; this -indicates early hatching or more probably the action of predators. - -In northern latitudes eggs or young turtles may over-winter in the -nest if deposition is late in the season. In northern Indiana Evermann -and Clark (1920:595) found a nest on November 16 that contained -"well-formed young" and believed that the turtles would have wintered -in the nest. Conant (1951:160) was of the opinion that most eggs -probably hatch in early fall, but that some do not hatch until spring. - -The hatching of eggs of _muticus_ has been described by Muller -(1921:183). According to him, the forelimbs first emerge through the -shell and enlarge the opening. There is an "egg tooth below the -flexible proboscis" but "it does not seem to be used in escape from -the eggs, and is dropped a week after hatching." Hatchlings burrow -almost straight upward through the sand leaving the egg shell below -the surface and a hole in the sand about an inch in diameter. Muller -found that young turtles emerge from the nests in the night or early -morning and always go downhill probably influenced in their movements -by the open sky and sloping beach. Anderson (1958:212-15) found that -hatchlings of _muticus_ leave nests within the first three hours after -sunset and travel a direct route to the water. He discovered that -hatchlings are active on the surface of the sand at night and -generally show a positive reaction to light (moonlight, flashlight), -whereas, in daytime, there is a negative reaction to bright sunlight -(causing the turtles to bury themselves in sand). Anderson believed -that the positive response to light at night is not correlated with -the water-approach behavior of hatchlings, but that movements to water -are possibly influenced by a negative reaction to dark masses of -environment (such as shadows formed by landward forests). - - -_Age and Growth_ - -Goff and Goff (1935:156) found that hatchlings of _ferox_ average 8.82 -grams (extremes, 8.50 to 9.25); one of these, UMMZ 76755, is -illustrated in Plate 31. Muller (1921:184) recorded measurements of -five hatchlings of _muticus_; the average measurements (in cm., -extremes in parentheses) were: length of carapace, 3.54 (3.43 to -3.67); width of carapace, 3.20 (3.10 to 3.25); length of plastron, -2.54 (2.47 to 2.60). I recorded measurements of 32 hatchlings (three -clutches combined) of _muticus_ on August 16; the turtles hatched on -August 4 to 6 from eggs collected along the Pearl River, Louisiana. -The average measurements (in mm., extremes in parentheses) of the 32 -turtles were: length of carapace, 41.3 (34.0 to 45.0); width of -carapace, 38.6 (31.0 to 40.0); length of plastron, 30.1 (25.0 to -32.0). These turtles have circular umbilical scars averaging -approximately two millimeters in diameter. The smallest hatchling that -I have seen measures 21.0 millimeters in plastral length (_T. m. -muticus_, INHS 3458). There are no data to indicate a difference in -size of hatchlings among the American species of soft-shelled turtles. -The average plastral length of most hatchlings probably is 28.0 to -30.0 millimeters. - -Owing to the lack of a horny epidermal covering of the carapace and -plastron, soft-shelled turtles are not so well suited to studies of -age and growth as are the "hard-shelled" species, which have visible -impressions of growth annuli on the epidermal scutes. Mattox -(1936:255) found annular rings in the long bones of specimens of -_Chrysemys_ and suggested that it is tenable to correlate the number -of rings with the age of the turtle. - -Mitsukuri (1905:265) reported that in hatchlings of _Trionyx sinensis_ -the length of the carapace averages 2.7 centimeters (hatchlings of -_sinensis_ seem to average smaller than any American species), and -that the average length of carapace (cm.) at the end of the first year -is 4.5, second year 10.5, third year 12.5, fourth year 16.0, and end -of fifth year 17.5; he stated also that females of _sinensis_ are -sexually mature in their sixth year. Breckenridge (1955:7-9) computed -a growth curve based on 11 recaptures of females of _spinifer_ in -Minnesota; his data on rate of growth for the first five years do not -differ appreciably from those of Mitsukuri. As most females of -_spinifer_ are sexually mature when the carapace is about 11 inches -long, the age at sexual maturity is approximately 12 years according -to Breckenridge (_op. cit._:8, Fig. 4). The discrepancy in age of -females at the size of attainment of sexual maturity (Mitsukuri--six -years; Breckenridge--12 years) is, in part, rectified by the fact that -_Trionyx sinensis_ probably is a smaller species. Also, Breckenridge's -computation of the growth curve is based on continuously decreasing -increments of growth and seemingly eliminates consideration of the -probable marked decrease in rate of growth that occurs when sexual -maturity is attained--a phenomenon noted in other species of turtles. -I think that increments of growth of immature turtles are, on the -average, larger than those of sexually mature turtles. Judging from -these criteria, the age of a female of _spinifer_ at sexual maturity -is less than 12 years, and turtles having carapaces 17 to 18 inches in -length (maximal size for _spinifer_) would be older than 53 years -(_op. cit._:9). Occasional individuals, however, may greatly exceed -the usual growth rate in which event large adults may be younger than -50 years. - -Females of _muticus_ are sexually mature when the plastron is 14.0 to -16.0 centimeters long, which corresponds to a carapace 19.6 to 22.4 -centimeters (about 7-3/4 to 8-3/4 inches) long (average CL/PL -approximately 1.4, see Fig. 13). The smaller adult females probably -mature sexually in their sixth year, but most probably do so when -seven years old. Accordingly, some _T. spinifer emoryi_, which are -sexually mature at a plastral length of 16.0 centimeters, are also -sexually mature in their seventh year, whereas most _spinifer_ -(sexually mature at a plastral length of 18.0 to 20.0 cm., -corresponding to a length of carapace of 25.2 to 28.0 cm. or about 10 -to 11 inches) probably become sexually mature in their ninth year, and -some when eight years old. Most males of _spinifer_ are sexually -mature when the plastron is 9.0 to 10.0 centimeters long (length of -carapace 12.6 to 14.0 cm. or 5 to 5-1/2 inches), whereas males of -_muticus_ and some _T. spinifer emoryi_ are sexually mature at a -plastral length of 8.0 to 9.0 centimeters (length of carapace 11.2 to -12.6 cm. or 4-1/2 to 5 inches). The smaller adult males are probably -sexually mature in their fourth growing season. Breckenridge (_op. -cit._:7, Tab. II) commented on the abundance of females between five -and 12 inches in length, and males that ranged in length from five to -seven inches. The abundance of turtles in these size ranges is -probably due, in part, to a slowing of the rate of growth indicating -the approach of sexual maturity; the abundance of the smallest males -is especially in accord with the size at sexual maturity of males -(about five inches). - -The largest acceptable record of size of _spinifer_ is 18 inches in -length of carapace (Breckenridge, 1957:232). Stockwell (1878:402), -however, wrote that females of _spinifer_ attain "an extreme length of -from twenty-four to twenty-eight, and, in rare instances, thirty -inches, with an average length of carapace of fifteen to eighteen," -and True (1893:152) mentioned lengths of two feet or even more. -Turtles 17 to 18 inches long are doubtless rare and probably about 60 -years old. A specimen of _ferox_ lived the longest time in -captivity--25 years (Pope, 1949:304). Individuals of _ferox_ probably -exceed the maximum recorded length of carapace of 18-1/2 inches -(Agassiz, 1857:401). The head of a _ferox_ having a width of 3-1/2 -inches (Wright and Funkhouser, 1915:120) corresponds to a length of -carapace of approximately 22-1/2 inches (PL/HW == 4.9; CL/PL == 1.3). -De Sola and Abrams (1933:12) wrote that _ferox_ in the Okefinokee -Swamp, Georgia, attains a length of two feet. The largest female of -_muticus_ of which I have record is 21.5 centimeters in plastral -length (KU 2308), a measurement corresponding to a carapace about 13 -inches long. - - -Mortality - -Man, in one sense or another, is a great enemy of soft-shelled -turtles. Those caught by fishermen are destroyed because of the -erroneous belief that they are harmful to fish populations. Some are -drowned in hoop-nets or gill nets used by commercial fishermen. Many -softshells are used by man for food. Herald (1949:118-19) reported the -results of spraying an area with DDT and mentioned a 10-inch -individual of _ferox_ that was eating a dead bluegill, and which -"probably died as a result of ingesting contaminated food." - -Predation on eggs probably accounts for most mortality. Hamilton -(1947:209) reported tracks of spotted skunks, raccoons and foxes seen -about destroyed nests, and Cahn (1937:183) incriminated skunks and -raccoons. Goldsmith (1945:449) reported a raccoon that unearthed seven -nests in one night. Little and Keller (1937:221) wrote of egg shells -found in the sand (probably not as a result of hatching), and Muller -(1921:182) reported egg shells around dug-up nests, suggesting such -predators as "ground moles," raccoons and crows. Chesser (_in_ Harper, -1926:416) said that in the Okefinokee Swamp the jackdaw (fish crow), -raccoon, bear and domestic dogs will eat the eggs. Wright and -Funkhouser (1915:122) recorded a young _ferox_ in the stomach of a -water moccasin (_Agkistrodon piscivorus_), and suggested that young -soft-shells probably are food of larger snakes. Kellogg (1929:26) -wrote that stomachs of two alligators each contained one soft-shelled -turtle. Newman (1906:136) found that young captives were eaten by -individuals of _Chrysemys_ and _Sternothaerus_, and I found that they -were eaten by _Kinosternon_. Mitsukuri (1905:261-62) stated that -first- and second-year individuals of _T. sinensis_ are eaten by the -adults. - -Breckenridge (1960) wrote that a clutch of eggs probably failed to -develop because of an "... unusually cool season." Evermann and Clark -(1920:595) stated that "many young appear to perish during the first -winter." They (_op. cit._:594) found two eggs submerged in two feet of -water and it is supposed that they never hatched. Dundee (1950:139) -reported remains of soft-shelled turtles left on the mud of a dried -swamp. - - -Parasites - -Muller (1921:182) found maggots in a few eggs of a clutch, but thought -that only the infertile and decomposing eggs were infested. I removed -a hard, spherical cyst from the hind leg of a preserved softshell -(TU). A captive hatchling (TU 17304) died as the result of a -continuously enlarging and deepening hole on the top of its head; I -could not discern a visible parasite with the naked eye. I found 25 -leeches (_Placobdella parasitica_, largest about 13 mm.; identified by -Dr. Kenneth B. Armitage, Department of Zoology, University of Kansas) -in association with 11 _T. m. muticus_ (number per turtle not known) -that were collected from the Kansas River at Lawrence, Douglas County, -Kansas. Evermann and Clark (1920:596) reported a few nematodes in the -stomachs of some _spinifer_, and three nematodes are listed by Harwood -(1932:46, 60, 62, 66) in the same species. Hughes, Higginbotham and -Clary (1941) have listed the known reptilian hosts of parasitic -trematodes, and Hughes, Baker and Dawson (1941) have done the same for -tapeworms. The species of parasites and their trionychid hosts are -listed below. - - TREMATODA - _Trionyx ferox_: _Neopolystoma orbiculare_ _Vasotrema amydae_ - _Neopolystoma rugosa_ _Vasotrema attenuatum_ - _Polystomoides coronatus_ _Vasotrema robustum_ - _Teloporia aspidonectes_ - - _Trionyx muticus_: _Crepidostomum cooperi_ _Opisthorchis ovalis_ - - _Trionyx spinifer_: _Hapalorhynchus evaginatus_ _Vasotrema amydae_ - _Opisthorchis ovalis_ _Vasotrema attenuatum_ - _Polystomoides coronatus_ _Vasotrema longitestis_ - _Teloporia aspidonectes_ _Vasotrema robustum_ - - CESTODA - _Trionyx ferox_: _Proteocephalus trionychinus_ - - _Trionyx spinifer_: _Proteocephalus testudo_ - - NEMATODA - _Trionyx spinifer_: _Camallanus trispinosus_ _Spiroxys amydae_ - _Falcaustra chelydrae_ - - -Economic Importance - -Several authors have mentioned softshells as a food item much sought -after by man. The commercial value of these turtles has been -summarized by Clark and Southall (1920:15-16). Softshells are consumed -in quantity only in small towns near the place of capture. They are -found only occasionally in the markets of large cities because the -turtles are little known and the palatability of their flesh is -unappreciated. Also, they do not stand shipment so well as other -turtles, and they are "not so meaty as the snapper; so there is more -waste" (Clark and Southall, _loc. cit._). Little and Keller (1937:221) -reported living individuals for sale at the market in Ciudad Juarez, -Chihuahua; however my inquiry at markets in Juarez in the summer of -1959 disclosed no evidence of recent sale of soft-shelled turtles. In -the southeastern United States the demand is perhaps greater than in -other regions. I have noted softshells in the market at New Orleans, -and Oliver (1955:19) has mentioned the sale of "some 146,600 pounds" -in one recent year in Florida. Over most of their range, however, -there probably is no general demand for softshells and no special -efforts are made to capture them. Softshells have been raised -successfully on "turtle farms" in Japan (Mitsukuri, 1905). True -(1893:152) wrote that "The eggs also are considered very excellent." - -Softshells generally are condemned by fishermen because of the -mistaken belief that they are detrimental to fish populations. Food of -softshells is principally crawfish and insects. Fish comprise a small -proportion of the diet (frequency 1.9% in Michigan, Lagler, 1943: Tab. -9). Most of the fishes eaten seem to be small minnows. Probably fish -would comprise a larger percentage of the diet if they could be -caught. I doubt that a softshell can pursue and capture a healthy fish -in natural waters. Recently dead fish are eaten and perhaps fish eggs, -and senile and decrepit fishes. There is no evidence that soft-shelled -turtles are active predators on any kind of fish. Of course in -congested areas such as ponds of fish hatcheries, it is desirable to -eliminate the turtles. The known food habits of soft-shelled turtles -suggest that they compete with game fishes for food, but there is no -information on the intensity of competition (Lagler, _op. cit._:305). - -The combined statements of many authors in their general accounts of -food habits (for instance, Babcock, 1919:425) have tended to create -the erroneous belief that soft-shelled turtles harm waterfowl. To my -knowledge the only basis for this belief is the statement of Wright -and Funkhouser (1915:123) that according to the natives of the -Okefinokee Swamp, the larger turtles "devour also such waterfowl as -are unfortunate enough to be taken unaware by these reptiles." Perhaps -an occasional waterfowl is eaten, but the present information on kinds -of food eaten certainly does not warrant the destruction of -soft-shelled turtles. There may be some mortality in congested areas -such as game refuges where young birds crowd the surface of the water. - -The kind of bait successfully used in trapping softshell turtles -suggests that they are of some value as scavengers. - - - - -EVOLUTIONARY HISTORY - - -Before attempting to reconstruct the history of soft-shelled turtles -in North America, it will be helpful to summarize the salient facts -concerning the distribution and relationships of the living forms, and -to comment on fossils. - - -Distribution - -The geographic range of the family Trionychidae in North America is -principally in the eastern two-thirds of the continent and contributes -to the well-known floral and faunal resemblance of eastern North -America to that of eastern Asia (Schmidt, 1946:149) because _Trionyx -ferox_ (see Fig. 18) resembles the species of the genus in Asia more -closely than it does any North American species. The Recent -distribution in America does not include the Neotropical region, -whereas the geographical range in the Old World extends south of the -equator (Fig. 1; Dunn, 1931:109, fig. 2; Gadow, 1909:333, fig. 72; -Hay, 1908:35, fig. 16). - -American softshells occur in all river systems in the United States -and the two adjacent river systems on the east coast of México that -drain into the Gulf of México. Softshells inhabit streams of the Great -Plains and occur westward to the foothills of the Rocky Mountains in -the western tributaries of the Mississippi River. Only _T. s. -spinifer_ occurs in the southern part of the Great Lakes-St. Lawrence -drainage. Softshells are absent from the Atlantic Coast drainage -except the Hudson River and those rivers at least south of (and -including) the Pee Dee River in South Carolina. - -_T. s. emoryi_ is not known to be indigenous west of the Río Grande -drainage, and has probably been introduced across the Continental -Divide via the Gila River in western New Mexico into the Colorado -River drainage of Arizona (Miller, 1946:46); the species undoubtedly -occurs in México on the Sonoran side of the Colorado River opposite -Baja California (Bogert and Oliver, 1945:417). - -In the summer of 1959, I trapped turtles and with a specimen in hand -inquired about softshells occurring in the inland drainages of -northern México. From two collecting stations on the Río Nazas in -Durango, only specimens of _Pseudemys_ and _Kinosternon_ were -obtained; local inhabitants had neither seen nor heard of softshells. -Flooded conditions in August of 1959 permitted trapping in only one of -the inland drainages of northwestern Chihuahua, the Río Santa María; -only specimens of _Kinosternon_ were obtained. Local residents near -that river as well as those living near the Río Casa Grandes and Río -del Carmen had not seen or heard of softshells. A person that I judge -to be a competent observer reported seeing a softshell in June of 1958 -in the Río Alamos (Arroyo Cuchujáqui) near Alamos, Sonora, in the Río -del Fuerte drainage on the west coast of México. I was a member of a -field party from the University of Kansas that visited that locality -in late January of 1959; only specimens of _Pseudemys_ and -_Kinosternon_ were collected. Possibly isolated populations occur in -streams of the Pacific Coast drainage of northern México. If so, they -may have entered Pacific Coast drainages by stream capture across the -Continental Divide. Several species of fish that are characteristic of -the Río Grande traversed the Sierra Madre Occidental at some former -time (presumably via the Río Conchos and Río Papigochic) and occur in -the Yáqui River drainage (Meek, 1904:xxxviii, xlvii; Miller, -1959:214-15, 217). Because of the probability that the Río Nazas at -some former time flowed north into the Río Grande (Meek, _op. -cit._:xxxiv), it is notable that softshells are absent in the Río -Nazas drainage; the Big Bend turtle, _Pseudemys scripta gaigeae_, -occurs in both drainages. - - -Relationships - -Characters of _Trionyx ferox_ suggesting a closer resemblance to some -Old World members of the family than to the other three American species -are: large size; marked difference between juvenal and adult patterns on -the carapace; the marginal ridge; and the longitudinal ridgelike -prominences on the carapace, especially in juveniles. Other characters -of _ferox_ suggesting a corresponding, but less marked resemblance to -Old World species of _Trionyx_ are: the large size of the eighth pair of -pleurals; the absence of callosities on the epiplastron and preplastra; -frequent fusion of the hyoplastra and hypoplastra (more than in -_spinifer_ or _muticus_); and tolerance of marine waters (more than -_muticus_ or _spinifer_). Some fossils also suggest alliance with -_ferox_ and some Old World members of the genus in their large size, -large eighth pair of pleurals, and occurrence in marine deposits; -several Old World species have been reported at sea (_Pelochelys_, _T. -triunguis_, _T. sinensis_). _T. ferox_ is monotypic and has the most -southeasterly displaced, geographic range. - -Because _ferox_ resembles softshells from the Old World more closely -than it does any American species, _ferox_ is assumed to be more closely -related to Old World softshells than to any American species, and, -because of resemblance to some fossils, _ferox_ is assumed to resemble -most closely the primitive, ancestral stock of softshells that occupied -North America. _T. spinifer_, _T. muticus_ and _T. ater_, which resemble -each other more closely than any of them resembles _T. ferox_ or any Old -World species, are considered autochthonous in North America. _T. -spinifer_ and _T. muticus_ are distinct, sympatric species. Burt -(1935:321) suggested that the two species "may be variants of the same -species." _T. ater_ is weakly differentiated from _T. spinifer emoryi_. -The species, _ferox_, _spinifer_ and _muticus_ are well-differentiated -and were considered by Agassiz (1857), Gray (1869) and Baur (1893) as -belonging to three different genera. - -In the widely distributed _T. spinifer_, the subspecies _spinifer_, -_hartwegi_ and _asper_ closely resemble one another; _asper_ seems most -distinct, whereas _spinifer_ and _hartwegi_ are terminal populations of -an east-west cline in one character. The subspecies _pallidus_, -_guadalupensis_ and _emoryi_ resemble one another more closely than any -resembles any of the subspecies mentioned immediately above; _T. s. -pallidus_, however, is annectent. _T. s. pallidus_ and _guadalupensis_ -represent terminal populations of clines in several characters, some of -which occur in _emoryi_, but that subspecies is more distinct from -_pallidus_ and _guadalupensis_ than those subspecies are from each -other. _T. s. emoryi_ is the most variable subspecies. _T. ater_, known -only from a restricted area in central Coahuila, is most closely related -to _T. s. emoryi_, and possesses some characters judged to represent the -attenuation of the geographic cline in _pallidus_, _guadalupensis_ and -_emoryi_ mentioned above. Some characters of _ater_ show alliance to the -species _muticus_. Of _T. muticus_, whose geographic range is removed -from that of _ater_, there are two subspecies. Four subspecies of -_spinifer_ (_spinifer_, _hartwegi_, _pallidus_ and _asper_) intergrade -in the Mississippi River drainage of Louisiana; few specimens, however, -are typical of _asper_. The subspecies of _muticus_ do not show definite -evidence of intergradation. To facilitate quick reference, the -occurrence of some characters that are shared by, or are approximated -in, two or more forms are listed in Table 10. In addition to external -characters, some ratios emphasize the clinal relationship between _T. s. -pallidus_, _guadalupensis_, and _emoryi_ mentioned above. Of especial -interest is the frequent resemblance of those subspecies and _T. ater_ -to _T. ferox_ (dorsal pattern on limbs of adults, reduction in anterior -tuberculation, wide head, narrow carapace, and short snout), and the -less marked resemblance of _T. muticus_ to _T. ferox_; not shown in -Table 10 is the resemblance of _ferox_ to _T. muticus calvatus_ in -having thick, black-bordered postocular stripes. Some populations of _T. -s. emoryi_ resemble _T. muticus_ in the corresponding size at sexual -maturity and in having well-developed plastral callosities. It is -notable that the occurrence of _ater_, and to a lesser extent that of -_T. s. emoryi_, which resembles _ferox_ (and _muticus_), is in the -southwestern United States and northern México. - - TABLE 10. Frequency of Selected Characters Among Species and - Subspecies of Trionyx in North America. Characters of muticus - Refer to the Typical Subspecies; Horizontal Dashes Connecting - X's Indicate that Computations for Those Subspecies Were - Combined; Vertical Dashes Indicate that the Subspecies Is - Intermediate Between the Adjacent Subspecies. - - Column headings: - - A: _ferox_ - B: _spinifer_ - C: _hartwegi_ - D: _asper_ - E: _pallidus_ - F: _guadalupensis_ - G: _emoryi_ - H: _ater_ - I: _muticus_ - - =====================================+=================================== - | Species and subspecies - Characters +---+---+---+---+---+---+---+---+--- - | A | B | C | D | E | F | G | H | I - -------------------------------------+---+---+---+---+---+---+---+---+--- - Juvenal pattern: | | | | | | | | | - black spots, ocelli | | X | X | X | | | | | - | | | | | | | | | - white dots | | | | | X | X | X | X | - -------------------------------------+---+---+---+---+---+---+---+---+--- - Pattern on snout: | | | | | | | | | - acute angle (reduced in _muticus_) | X | X | X | X | X | | | | X - | | | | | ¦ | | | | - triangular | | | | | X | X | X | X | - -------------------------------------+---+---+---+---+---+---+---+---+--- - Pattern on side of head: | | | | | | | | | - contrasting marks | X | X | X | X | X | X | | | - | | | | | | ¦ | | | - non-contrasting marks (distinct | | | | | | ¦ | | | - stripe in _muticus_) | | | | | | X | X | X | X - -------------------------------------+---+---+---+---+---+---+---+---+--- - Pattern on limbs of adults: | | | | | | | | | - contrasting | | X | X | X | X | X | | | - | | | | | | ¦ | | | - reduced or absent | X | | | | | X | X | X | X - -------------------------------------+---+---+---+---+---+---+---+---+--- - Tuberculation (anterior edge of | | | | | | | | | - carapace): | | | | | | | | | - conical, equilateral | | X | X | X | X | | | | - | | | | | | | | | - reduced or absent | X | | | | | X | X | X | X - -------------------------------------+---+---+---+---+---+---+---+---+--- - Head (PL/HW, fig. 3): | | | | | | | | | - wide | X | | | X | | X | X | X | - | | | | | | | | | - narrow | | X | X | | X | | | | X - -------------------------------------+---+---+---+---+---+---+---+---+--- - Carapace (CL/CW, fig. 4): | | | | | | | | | - wide | | X | X | X | X | X | | | X - | | | | | | ¦ | | | - narrow | X | | | | | X | X | X | - -------------------------------------+---+---+---+---+---+---+---+---+--- - Level of Carapace Width (CL/PCW, | | | | | | | | | - fig. 5): | | | | | | | | | - middle of carapace | X | X | X | X | | | | | X - | | | | | | | | | - farther posteriorly | | | | | X | X | X | X | - -------------------------------------+---+---+---+---+---+---+---+---+--- - Snout (HW/SL, fig. 6): | | | | | | | | | - long | | X---X | X | X---X | | | X - | | | | | ¦ ¦ | | | - short | X | | | | X---X | X | X | - -------------------------------------+---+---+---+---+---+---+---+---+--- - - -Fossils - -The known occurrence of fossil trionychids throughout the world -indicates a former distribution more widespread than the family has -today; the principal difference in the former and present distributions -is the lack of living softshells in Europe. - -I have not studied in detail the many fossil remains but such -examination as I have made of them suggests that many of the characters -used as a basis for distinguishing fossil forms in North America are -subject to individual variation or are of no diagnostic value in the -living species (Hummel, 1929:769). Knowledge of the variation in the -living species of the Old World would aid in adequately appraising the -North American fossils. Some osteological characters of the three living -American species (excluding _ater_) together with data on variation -within a given species are mentioned below. Some differences in skulls -of the three species already were mentioned in the section "Osteological -Characters." Because most fossil remains are those of the carapace and -plastron, attention is here given to those structures. - -_Widened alveolar surfaces of jaws._--An ontogenetic variation -affecting large skulls of _T. ferox_ and some individuals of _T. -spinifer asper_; presumably confined to females. Of especial interest -is its presence in some populations of _asper_ that are not otherwise -distinguishable (external characters) from the rest of the individuals -comprising that subspecies. - -_Sculpturing._--No differences in pattern (generally of anastomosing -ridges) on carapace or plastron; fineness or coarseness seemingly -correlated with size; frequency and kind (knoblike or ridgelike) of -bony prominences on carapace variable; bony prominences confined to -species _spinifer_ and _ferox_, occurring principally on large -females. - -_Fontanelles of carapace._--Closure more or less correlated with -increasing size, although much variation noted between individuals of -same size; small individuals have fontanelles confluent (medially), -thus separating nuchal from contact with first neural and first pair -of pleurals. - -_Number and arrangement of neurals and pleurals._--Neurals number six -to nine, usually seven or eight; pleurals number seven or eight pairs, -and may or may not be in contact with each other posteriorly; eighth -pair of pleurals when present reduced, never contacting seventh -neural; arrangement posteriorly variable (see Fig. 16 and Tab. 5). - -_Plastral callosities._--Increase in size with advancing age causing -corresponding reduction in size of plastral vacuity; relatively best -developed in _muticus_ (all elements touching medially on KU 41380 -leaving no plastral vacuity); probably no callosities on preplastra or -epiplastron of _ferox_; callosity on epiplastron of _spinifer_ not -covering entire surface (as it may in _muticus_). - -_Epiplastron._--Obtusely-angled (greater than 90 degrees) in -_muticus_; acutely-angled (90 degrees or less) in _ferox_ and -_spinifer_. - -_Hyo-hypoplastral suture._--Usually present, but occasionally absent, -in all species. - -The fossil turtles of North America have been treated monographically by -Hay (1908), who apportioned fossil trionychid remains into eight genera -(three living) of two families. Recently, Romer (1956:514) relegated all -trionychid fossils to the genus _Trionyx_. Characters, as gleaned from -Hay's synopsis (_op. cit._:465-548, Pls. 85-113), that seem especially -worthy of taxonomic consideration are: (1) The presence of a preneural, -which is not known to occur in the living American species (seemingly -the preneural is fused with the first neural and represents the elongate -first neural in living species); (2) The large eighth pair of pleurals, -especially when they contact the seventh neural; (3) The thickness of -the costal plates, a condition probably correlated with the size of some -fossils, which are larger than any living species (for example, Hay, -_op. cit._:518, mentioned the greatest dimension of a nuchal bone as -approximately 300 mm.). - -The approximate extent of the known horizontal distribution of fossils -is indicated in Figure 24. A comparison of known localities of fossils -and the distribution of living softshells (introduced population of _T. -s. emoryi_ in Colorado River drainage omitted) shows that the -distribution was more widespread in former times. Localities of fossils -are centered on the Atlantic Coast from New Jersey to North Carolina and -in the Rocky Mountain-Great Plains region from Alberta and Saskatchewan -to northwestern New Mexico; the oldest fossils, which occur in each -region, are found in Upper Cretaceous deposits. Many fossils occur in -marine and brackish water deposits. Most localities depicted on the map -are mentioned by Hay (1908:36-37, 465-548). Other localities included on -the map are in southern Alberta (Russell, 1929:164; 1930:27; Sternberg, -1926:104), southern Saskatchewan (Russell, 1934:109), northern South -Dakota (Hay, 1910:324), central Utah (Gilmore, 1946), western Colorado -(Schmidt, 1945), southwestern Kansas (Galbreath, 1948:284), southeastern -Texas (Hay _in_ Stejneger, 1944:65), southern California (Brattstrom, -1958:5), and northeastern Coahuila, México (Mullerried, 1943:623). Hay's -record of the living _Platypeltis_ (= _Trionyx_) _ferox_ and other -remains from the Peace Creek formation in Hillsborough County, Florida -(_op. cit._:548), presumably is the same record mentioned by Pope -(1949:305). - - [Illustration: FIG. 24. Geographic distribution of Recent - soft-shelled turtles (bordered by heavy black line) and fossil - trionychids (black circles) in North America. The introduced - population of _T. s. emoryi_ in the southwestern United States - is not shown.] - -Ameghino (_in_ Hay, _op. cit._:35) recorded specimens of a trionychid -from the Cretaceous of Patagonia, a record that, at present, cannot be -accepted (Simpson, 1943:423). Mullerried (_loc. cit._) also mentioned -some trionychid remains that were housed in Tuxtla Gutierrez, Chiapas, -México, (material now lost), but their geographical provenance was -unknown. The former extent of range southward is not known; it is -improbable that trionychids occurred in South America (Simpson, -1943:423). - - -Phylogeny - -The occurrence of _T. ferox_ in Florida and the suggestion of -_ferox_-like characters in turtles from southwestern Texas and northern -Mexico presents a distributional pattern that resembles the disjunct -ranges of many other pairs of closely related taxa. The clear-water -ponds in central Coahuila, which are inhabited by _ater_, correspond to -aquatic habitats supporting _ferox_ in Florida. The splitting of the -geographic range into eastern and western parts possibly resulted from a -southward shift of colder climates in glacial stages of the Pleistocene, -or from the development of an intervening arid region in the late -Miocene and Pliocene (see discussions in Martin and Harrell, 1957, and -Blair, 1959). An initial separation of range by an arid environment in -the Pliocene may have been terminated by the colder climates in the -Pleistocene. - -The degree of morphological difference between _ferox_ and the forms in -southwestern Texas and northern México, suggests that the time of -separation antedated the Pleistocene. - -Trionychid turtles may have traversed the Bering land bridge between -Asia and North America in late Mesozoic times for they occur as fossils -on the Atlantic Coast and in the Rocky Mountain-Great Plains region in -Upper Cretaceous deposits. Shallow, inland seas may have afforded no -barrier to the dispersal of softshells which presumably were tolerant of -saline waters. The orogeny and volcanic action with subsequent erosion -and sedimentation of the Rocky Mountain system, which was later -accompanied by drier climates, tended to obliterate suitable habitats in -the western United States; softshells persisted at least until the Upper -Eocene on the west coast (Brattstrom, 1958:5). The factors responsible -for the disappearance of softshells on the Atlantic Coast probably were -related to the glacial advances in the Pleistocene; the most recent -fossils known occur in Miocene deposits. - -The relationships of the living species and subspecies were probably -correlated with geologic change in aquatic environments and drainage -patterns. These changes probably included stream capture, flooding, -drought, uplifting and planation. A hypothetical, evolutionary history -is presented in the phylogenetic diagram where letter symbols represent -species and subspecies, and grouped symbols (referred to in subsequent -paragraphs) represent ancestral stocks. - - Pliocene Pleistocene Recent - ========================================================================== - - +--F-----------------------------------F (_ferox_) - | - | +---------Mm (_muticus muticus_) - | +--M------------------+ - | | +---------Mc (_muticus calvatus_) - | | - FMSA-+ | +--Ss (_spinifer spinifer_) - | | +------+ - | | | +--Sh (_spinifer hartwegi_) - | | +--Ssha-+ - +--MSA-+ | | - | | +---------Sa (_spinifer asper_) - | | - | +--S---+ +--Sp (_spinifer pallidus_) - | | | +--Spg-+ - | | | | +--Sg (_spinifer guadalupensis_) - +--SA--+ +--Sepg-+ - | | - | +--Se-----Se (_spinifer emoryi_) - | - +--A---------------------A (_ater_) - - -------------------------------------------------------------------------- - -An arid environment in the central and southern United States and -northern Mexico may have increased in area especially southward from -Miocene times into the Pliocene (Dorf, 1959:189, 191). The combination -of physiographic changes and aridity, which modified the mesic, -essentially continuous, aquatic habitats, may have isolated and aided in -the differentiation of the _ferox_, _muticus_ and _spinifer_ stocks. -Encroachment of the Eocene seas, the maximal extent of which -corresponded to the Gulf Coastal Plain and included a northerly -extension as far as Cairo in southern Illinois (Mississippi embayment), -possibly was an initial barrier isolating the _ferox_ stock of the east. - -In the late Miocene or early Pliocene, the MSA (_muticus-spinifer-ater_) -stock presumably occupied a large region of the central United States, -which extended southward into northern México and along the Gulf Coast -at least as far as Alabama. Farther eastward, the _ferox_ stock was -isolated in more mesic, probably swampy, marshy habitats. - -Later, in the southwestern part of the range of the MSA stock (southern -Texas and northern México), the SA and _muticus_ stocks were separated. -The _muticus_ stock occurred to the northeastward, and presumably no -farther south than the area included within the present drainage basin -of the Colorado River. Southward, the SA stock was isolated into several -populations that are today represented by _ater_ and _T. s. emoryi_, the -most variable subspecies; the distribution of the most distinctive -population of _emoryi_ indicates a former isolated inland drainage. The -multiple fragmentation of the SA stock presumably terminated by the end -of the Pliocene. The progenitors of _T. ater_ probably closely resembled -_ferox_. _Trionyx ater_ and _T. ferox_ resemble each other -morphologically and in habitat. Therefore, the progenitors of _ater_ are -considered to have undergone comparatively little differentiation. - -The _spinifer_ stock, occurring principally in the area included within -the present drainage basin of the Río Grande, extended its geographic -range eastward and became sympatric with _muticus_ and _ferox_. An -expansion of range necessarily demands more mesic conditions; these were -perhaps afforded by the pluvials (wet, rainy ages) that were coincident -with the glacial periods in the Pleistocene (Antevs, 1948:168). The -pluvials permitted the isolated populations of the _spinifer_ stock to -unite, and permitted that stock to extend its range eastward. The -concurrent continental glaciation permitted the _spinifer_ stock to -extend its range eastward only in a belt approximately 300 miles wide -along the Gulf Coast, and also displaced the ranges of _ferox_ and -_muticus_ to southern latitudes. Perhaps _ferox_ was less tolerant of -decreased temperatures or changes in habitat than was the _spinifer_ -stock but, for some unknown reason, _ferox_ did not extend its range -westward. Because _T. ater_ closely resembles _T. s. emoryi_, continued -isolation of _ater_ since the beginning of the Pleistocene seems -unlikely and _ater_ may have been reunited in subsequent pluvial periods -with the _spinifer_ (_emoryi_) stock. A climatic fluctuation between -relatively wet and dry periods is corroborated by studies of soil -profiles in Trans-Pecos Texas (Bryan and Albritton, 1943). - -The separation of the range of _spinifer_ in the general region of -western Louisiana, resulting in the differentiation of the _spinifer_ -group of subspecies to the east and the _emoryi_ group of subspecies to -the west, and the differentiation of _T. s. asper_ and _T. m. calvatus_, -both having corresponding western limits of distribution (Mississippi -River drainage), are associated with the activities of the Mississippi -River and its flood-plain. The combined effects of the pluvials and -interpluvials seem responsible for changes in the lower Mississippi -Valley. Great volumes of summer melt-water in the glacial stages greatly -increased the breadth of the channel of the lower Mississippi River -(corresponding to the northern extent of the Mississippi embayment; -Hobbs, 1950), and this, coupled with the encroachment of Pleistocene -seas (especially in the Mississippi embayment) in the interglacial -periods, perhaps separated populations eastward represented today by _T. -m. calvatus_ and _T. s. asper_. The _spinifer-hartwegi_ stock probably -developed in southern Louisiana in association with the meandering of -the Mississippi River and its tributaries, and its broad alluvial plain. -The biota of that plain differed from that adjacent to the east or west -(see discussion in Viosca, 1944) and constituted a barrier, of a sort, -to free communication between the east and west. Westward the _emoryi_ -group of subspecies differentiated, its eastern limit probably being the -Red River, which followed its own course to the Gulf along the lowlands -on the west side of the Mississippi Valley and did not empty directly -into the Mississippi until Recent times (Holland, 1944:20). There was -not an equally-marked, corresponding separation of the range of -_muticus_. However, the juvenal pattern of the subspecies _muticus_ that -inhabits the Gulf Coast streams is slightly different (having less short -lines) from that of _muticus_ elsewhere. - -The Río Grande (inhabited by _emoryi_) presumably had its own exit to -the Gulf whereas rivers westward to (and including) the Red River -(inhabited by _pallidus-guadalupensis_ cline) probably were joined near -their mouths forming a large drainage system. Hubbs (1957:93) pointed -out that the Río Grande-Nueces divide also limits a large number of -species of fish. The differentiation of _pallidus_ and _guadalupensis_ -is possibly due to a difference in the salt content of waters that drain -the Edward's Plateau (see page 547), or to isolation of those subspecies -in separate drainage systems that had their own exits to the Gulf. - -In the lower Mississippi drainage, the _spinifer-hartwegi_ stock -extended its range northward following the retreat of the last glacial -stage, and differentiated into those two subspecies in the upper -Mississippi drainage and Great Lakes-St. Lawrence drainage system. - -I have seen one specimen (UMMZ 59198) from the eastern part of the -Tennessee drainage (inhabited by _T. s. spinifer_) that resembles _T. s. -asper_ (occupying the Gulf Coast drainages of the southeast). This -resemblance tends to support the thesis of a former confluence of the -Coosa (Alabama River system) and Tennessee drainages as believed by some -malacologists to explain resemblances in molluscan fauna and as -corroborated by physiographical evidence (see discussion in van der -Schalie, 1945). - - -The Importance of the Study of Turtle Populations in Relation to the -History of River Systems - -In the Río Grande drainage the geographic distribution of the population -of _emoryi_ having orange color in males is approximately the same as -that of _Pseudemys scripta gaigeae_; the corresponding distributions -suggest that a part of the Río Grande drainage consisting of the Río -Conchos in Chihuahua and the Big Bend region of Texas was isolated in -former times. Accordingly, the known aquatic chelonian fauna in the -basin of Cuatro Ciénegas in central Coahuila, México, is endemic (except -_T. s. emoryi_). And the coincidence of the geographic ranges of _T. -muticus calvatus_ and _Graptemys pulchra_ in the southeast suggest a -former association of the included (Pearl to Escambia) river systems. -The occurrence of _T. s. pallidus_ in the Red River drainage indicates -that the Red River was formerly associated with the Gulf Coast streams -of eastern Texas and western Louisiana (inhabited by _pallidus_) and not -with the Mississippi River drainage. The lower Mississippi River valley -forms a prominent barrier to the eastern and western dispersal of many -kinds of species and subspecies of turtles. _T. m. calvatus_ and _T. s. -asper_, which occur in rivers of the Gulf Coast drainage east of the -Mississippi, are well-differentiated subspecies showing little or no -evidence of intergradation with their relatives in the Mississippi -River. The large faunal break provided by the Mississippi River would -seem to indicate greater age for that river than for other rivers of the -Gulf Coast drainage. - -A comparison of the distributions of _Trionyx_ and _Graptemys_ in Texas -suggests a faunal break between the drainage systems of the Brazos and -Colorado rivers. _Graptemys versa_ occurs in the Colorado and -Guadalupe-San Antonio drainages. To my knowledge _versa_ hitherto has -not been recorded from the latter drainage system. I have seen one -specimen of _Graptemys_ (custody of Gerald Raun, University of Texas) -from the Guadalupe River drainage, which I judge to be representative of -_versa_, and Olson (1959:48) has reported _Graptemys_ (probably _versa_) -in the San Antonio River. The distribution of _G. versa_ parallels in a -general way, the distribution of _T. s. guadalupensis_. _G. kohni_ and -_T. s. pallidus_ occur in the Brazos River and eastward. Also, it is -notable that the population of _T. m. muticus_ occurring in the Colorado -River drainage differs slightly (more black pigmentation) from the same -subspecies in the adjacent Brazos River system. - -There is much difference in the patterns of distribution and degree of -differentiation of different genera of aquatic turtles in the eastern -United States. Tinkle (1958:41-43, Figs. 49-55) concluded that a general -resemblance in the patterns of distribution of the different genera of -turtles was evidence that the rates of evolution were essentially the -same, assuming that each genus had had a similar time interval for -differentiation (_op. cit._:42). If this is true, corresponding patterns -of distribution might indicate the same relative age of the population -of turtles concerned. Generally, the genera of turtles that on -morphological grounds are considered the oldest and most primitive -(_Macroclemys_, _Chelydra_) show less differentiation into species and -subspecies than those considered younger and more recently evolved -(_Graptemys_, _Pseudemys_). In the genus _Graptemys_, much -differentiation occurs in the geologically, recently formed, Gulf Coast -drainage systems of the southeastern United States. It would seem then, -that faster rates of differentiation denote more recent genera, whereas -older genera are endowed with a "genetic senility" and are less subject -to change. - -Evidence of the relative age of two genera of turtles, as suggested by -their degree of differentiation into minor taxa, and the degree of -difference between populations of two genera that inhabit adjacent -drainage systems, may indicate the relative ages of particular river -systems. For example, the slight resemblance of _G. versa_ to _kohni_ -and the close resemblance of _T. s. guadalupensis_ to _pallidus_ in -Texas may reflect the age of the genus _Trionyx_ and the youth of the -genus _Graptemys_. Remembering that the genus _Graptemys_ is relatively -recently evolved and assuming _G. versa_ to be the most primitive and -ancestral species of the genus (at least it is monotypic, the most -aberrant species, and unlike any other species of the genus), it seems -logical to suppose that the physiographic changes responsible for the -Colorado-Brazos divide and the isolation of _versa_ occurred early in -the evolutionary history of the genus _Graptemys_. The degree of -differentiation of _Trionyx_ suggests that that genus is, comparatively, -much older, and that the same physiographic changes responsible for the -Colorado-Brazos divide and differentiation of the subspecies _pallidus_ -and _guadalupensis_ occurred late in the evolutionary history of the -genus _Trionyx_. - -In general, patterns of distribution of turtle populations support -physiographic evidence concerning changes in stream confluence and -relative age of river systems. - - - - -SUMMARY - - -In North America, soft-shelled turtles (genus _Trionyx_) occur in -northern México, the eastern two-thirds of the United States, and -extreme southeastern Canada. The genus fits the well-known Sino-American -distributional pattern. In North America there are four species. Three -(_ferox_, _spinifer_ and _muticus_) are well-differentiated and one -(_ater_) is not well-differentiated from _spinifer_. Characters of -taxonomic worth are provided by the following: size; proportions of -snout, head and shell; pattern on carapace, snout, side of head, and -limbs; tuberculation; sizes of parts of skull; number of parts of -carapaces; and, shape and number of some parts of plastra. Many features -show geographical gradients or clines. _T. ferox_ is the largest species -and _muticus_ is the smallest. Females of all species are larger than -males. With increasing size of individual, the juvenal pattern is -replaced by a mottled and blotched pattern in females of all species; -adult males of _spinifer_ retain a conspicuous juvenal pattern, whereas -the juvenal pattern is sometimes obscured or lost on those of _ferox_ -and _muticus_. The elongation of the preanal region in all males, and -the acquisition of a "sandpapery" carapace in males of _spinifer_ occur -at sexual maturity. There is a marked secondary sexual difference in -coloration in a population of _T. s. emoryi_ (side of head bright orange -in males and yellow in females). The sex of many hatchlings of _T. s. -asper_ can be distinguished by the pattern on the carapace. Slight -ontogenetic variation occurs in some proportional measurements. Large -skulls of _ferox_ and some _asper_ (those in Atlantic Coast drainages) -have expanded crushing surfaces on the jaws. Considering osteological -characters, _muticus_ is most distinct; there is less difference between -_ferox_ and _spinifer_ than between those species and _muticus_. - -_T. ferox_ is monotypic, confined to the southeastern United States, and -resembles Old World softshells more than it does any American species. -The northern part of the geographic range of _ferox_ overlaps that of -_T. s. asper_; there, the two species are ecologically isolated. _T. -spinifer_ is polytypic, has the largest geographic range, and is -composed of six subspecies, of which two are described as new -(_pallidus_ and _guadalupensis_). The subspecies are divisible into two -groups. One, the _spinifer_ group (_spinifer_, _hartwegi_ and _asper_) -is recognized by a juvenal pattern having black spots or ocelli; _asper_ -is the most distinctive and shows little evidence of intergradation in -the lower Mississippi River drainage with the _spinifer-hartwegi_ -complex, which, northward, is differentiated into two subspecies in -which there is an east-west cline in size of the ocelli on the carapace. -The _emoryi_ group (_pallidus_, _guadalupensis_, _emoryi_) is recognized -by a pattern of white spots; _emoryi_ is most distinctive. Each of -several characters behaves as a cline if traced from east to west -through the three subspecies. _T. s. pallidus_ intergrades with the -_spinifer-hartwegi_ complex in the lower Mississippi River drainage. _T. -s. emoryi_ is the most variable subspecies; in its most notable -population the males have orange coloration. _T. s. emoryi_ has been -introduced into the Colorado River drainage of Arizona. _T. ater_ most -closely resembles _T. s. emoryi_, but shows alliance with _T. muticus_ -and _T. ferox_. _T. ater_ is confined to ponds of crystal-clear water in -central Coahuila, México. _T. muticus_ is completely sympatric with -_spinifer_, and is composed of two subspecies (_muticus_ and -_calvatus_). _T. m. calvatus_ shows no evidence of intergradation in the -lower Mississippi River drainage with _T. m. muticus_, corresponding -somewhat to the relationship of _T. s. asper_ with the intergradient -population of _T. spinifer_ in the Mississippi River. - -Softshells have pharyngeal respiration and probably are incapacitated by -rotenone. _T. ferox_ and the subspecies of _spinifer_ occur in a wide -variety of fresh-water habitats; _muticus_ is more nearly restricted to -running water (especially in the northern parts of its range) than -_spinifer_, and may be less vagile than _spinifer_. _T. ferox_ is more -tolerant of marine and brackish waters than are _muticus_ or _spinifer_. -Small size and pallid coloration seem correlated with arid environments. -The largest species (_ferox_) and the smallest population of _spinifer_ -(resembling _muticus_) both occur in the southernmost part of the range -of the genus. Diurnal habits include basking on shores or débris in -water, floating at the surface, procuring food, and burrowing in shallow -and deep water (no observations for _spinifer_ and _muticus_ in deep -water). Softshells are principally carnivorous; the food consists mostly -of crawfish and insects; there is evidence of cannibalism involving -predation on first- and second-year-old turtles. The capture of food is -triggered primarily by movement of prey; sight seems to be more -important than smell to _Trionyx_ in capturing food. There is no -indication of a food preference between species; enlarged crushing -surfaces of jaws in some _ferox_ and _asper_ may be an adaptation for -feeding on mollusks. Schools of fish are reported to follow softshells, -and presumably acquire food that is dislodged by the grubbing and -scurrying of the turtles on the bottom. Softshells are wary. They are -good swimmers, and travel rapidly on land. The depressed body is an -adaptation for burrowing and concealment. Permanent growths of algae do -not occur on the dorsal surface of softshells. There is evidence of some -nocturnal activity, and a general parallel in habits between trionychids -and chelydrids. Softshells sometimes move overland; they move little in -aquatic habitats. The normal annual period of activity of _spinifer_ in -latitudes 40° to 43° is approximately five months from April into -September, depending on the weather; they hibernate under a shallow -covering of mud in deep water. The southernmost populations may be -active throughout the year. - -Males of _spinifer_ are sexually mature when the plastron is 9.0 to 10.0 -centimeters in length (some when 8.0 long), whereas those of _muticus_ -are sexually mature at 8.0 to 9.0 centimeters. In the mentioned size -range, the smaller adult males are probably in their fourth growing -season, and the larger males in their fifth. Most females of _spinifer_ -are sexually mature at a plastral length of 18.0 to 20.0 centimeters and -are probably in their ninth year; the smaller individuals probably are -in their eighth. Females of _muticus_ are sexually mature when the -plastron is 14.0 to 16.0 centimeters long. Most of these are seven years -old but some are only six years old. Some large females contain immature -ovaries. The near-maximum length of carapace of _spinifer_ is 18 inches, -and such turtles are perhaps 60 years old; _ferox_ perhaps attains a -length of two feet. - -_T. ferox_ deposits eggs from late March to mid-July, whereas northern -populations of _spinifer_ and _muticus_ usually deposit theirs from -mid-June to mid-July. Sandy sites are preferred for nests, although -movement to other sites occurs if the preferred sandy sites are -submerged or otherwise rendered unusable. _T. muticus_ limits its nest -sites to the open areas of sand bars and does not lay inland where it -must traverse vegetated areas, as does _spinifer_. Nests of _ferox_ and -_spinifer_ seem to differ from those of _muticus_ in being flask-shaped. - -The seasonal reproductive potential is perhaps less in northern -populations (averaging 20 eggs per clutch and only one clutch per -season) than in southern populations (averaging about 10 eggs per -clutch, but three clutches per season). Larger females deposit more eggs -than smaller females. Eggs laid in northern latitudes are slightly -smaller than those laid farther south. In any latitude the incubation -period probably is at least 60 days. Hatchlings presumably leave nests -at dusk, nighttime or dawn, and may winter over in eggs or nests. - -Man is a great enemy of softshells. Predation on eggs probably accounts -for most mortality. Physical conditions of the environment (overcrowding -of nest sites, inadequate hibernation sites) and probably some kinds of -parasitism contribute to mortality. Softshells are eaten locally and -sometimes appear in the market of large cities, but over most of their -range, there probably is no general demand and no special efforts are -made to capture them. Fish, mostly minnows, comprise a small proportion -of the diet. There is no evidence that softshells are active predators -on any kind of fish, but their known food habits suggest that they -compete with game fishes for food. Softshells are scavengers. - -Fossil material was not studied in detail. The fossil softshells -indicate a more widespread, former distribution. Some osteological -characters and their variation in the living species are mentioned as an -aid to future workers concerned with an assay of fossil remains. Fossils -occur in marine, brackish and fresh-water deposits, and many are much -larger than the living species; the oldest American fossils are of Upper -Cretaceous age. - -The interrelationships of the living species and subspecies suggest that -the species _spinifer_, _ater_, and _muticus_ are derivatives of a -_ferox_-like ancestor, and that they differentiated in North America; -most differentiation occurs in southwestern Texas and northern México -where characters of some populations indicate alliance with _ferox_. It -is hypothesized that aridity in the late Tertiary effected specific -differentiation by the modification and isolation of aquatic habitats. -Pluvial periods in the Pleistocene provided for confluence of aquatic -habitats and expansion of geographic ranges, and coupled with -physiographic changes, conceivably caused or enhanced some of the -subspecific variation. - - - - -LITERATURE CITED - - -References marked with an asterisk were not seen by the author. - - ADAMS, M. S., and CLARK, H. F. - - 1958. A herpetofaunal survey of Long Point, Ontario, Canada. - Herpetologica, 14(1):8-10, April 25. - - - ADLER, K. K., and DENNIS, D. M. - - 1960. New herpetological records from Ohio. Jour. Ohio Herp. Soc., - 2(4):25-27. - - - AGASSIZ, L. - - 1857. Contributions to the natural history of the United States of - America. Vol. I. Part II. North American Testudinata. Vol. II. - Part III. Embryology of the turtle. Little, Brown and Co., - Boston, pp. 233-452d; pp. 449-643, 27 pls. - - - ALLEN, E. R., and NEILL, W. T. - - 1950. The alligator snapping turtle _Macrochelys temminckii_ in - Florida. Spec. Publ. Ross Allen's Rept. Inst., 4:1-15, 6 figs., - May. - - - ALLEN, W. B., JR. - - 1955. Some notes on reptiles. Herpetologica, 11(Pt. 3):228, - November 30. - - - ANDERSON, P. - - 1942. Amphibians and reptiles of Jackson County, Missouri. Bull. - Chicago Acad. Sci., 6(11):203-220. - - - ANDERSON, P. K. - - 1958. The photic responses and water-approach behavior of hatchling - turtles. Copeia, 1958(3):211-215, 5 figs., August 28. - - - ANTEVS, E. - - 1948. Climatic changes and pre-white man. _In_ The Great Basin with - emphasis on glacial and postglacial times. Bull. Univ. Utah, - 38(20), Biol. Ser., 10(7):168-191, 1 fig., 1 table, June 30. - - - ATKINSON, D. A. - - 1901. The reptiles of Allegheny County, Pennsylvania. Ann. Carnegie - Mus., 1901-1902, 1(4):145-157. - - - BABCOCK, H. L. - - 1919. The turtles of New England. Mem. Boston Soc. Nat. Hist., - 8(3): 325-431, 16 pls., April. - - 1938. Field guide to New England turtles. New England Mus. Nat. - Hist., Nat. Hist. Guides, 2:1-56, 9 pls., November. - - - BARBOUR, T., and LOVERIDGE, A. - - - 1929. T ypical reptiles and amphibians. Bull. Mus. Comp. Zool., - 69(10): 205-360, June. - - - BARTRAM, W. - - 1791. Travels through North and South Carolina, Georgia, east and - west Florida, the Cherokee country, the extensive territories - of the Muscogulges, or Creek Confederacy, and the country of - the Chactaws; containing an account of the soil and natural - productions of those regions, together with observations on - the manners of the Indians. First Edition, Philadelphia, - xxxiv+522 pp., 8 pls. (including frontispiece), 1 map. - Plates unnumbered except "Plate IV" (dorsal view of head of - softshell), inserted between pages 282 and 283. - - - BAUR, G. - - 1887. Über die stellung der Trionychidae zu den übrigen - Testudinata. Zool. Anz., 10(242):96-102, January 17. - - 1888. Notes on the American Trionychidae. Amer. Nat., - 22(264):1121-22, December. - - 1891. On the relations of Carettochelys Ramsay. Amer. Nat., - 25:631-639, 3 pls., July. - - 1893. Notes on the classification and taxonomy of the Testudinata. - III. The genera of the Trionychidae. Proc. Amer. Phil. Soc., - 31:213-221, May 5. - - - BERGOUNIOUX, M. F.-M. - - 1932. Sur la place des _Trionyx_ dans la classification des - chéloniens. Compt. Rend. Acad. Sci., 195(26):1407-09, - December 27. - - 1936. Sur l'origine du groupe des Trionychoidés. Compt. Rend. Acad. - Sci., 203(21):1087-88, November 23. - - 1937. Chéloniens fossiles du Kiméridgien du Cap de la Hève. Bull. - Soc. Nat. Hist. de Toulouse, 71(1-2):180-91, 2 figs., 2 pls., - June 30. - - 1952. Remarques due les chéloniens fossiles de la famille des - Carettochelyidae. Compt. Rend. Acad. Sci., 234(23):2302-04, - June 4. - - - BEYER, G. E. - - 1900. Louisiana herpetology with a check-list of the batrachians - and reptiles of the state. Proc. Louisiana Soc. Nat., 1897-1899, - pp. 25-46. - - - BISHOP, S. C. - - 1923. Notes on the herpetology of Albany County, New York, III. - Copeia, 1923(125):115-20, December 31. - - - BLAIR, W. F. - - 1959. Distributional patterns of vertebrates in the southern United - States in relation to past and present environments. _In_ - Zoogeography, edit. C. L. Hubbs. Amer. Assoc. Adv. Sci., Publ. No. - 51, Washington, pp. 433-468, 11 figs., January 16. - - - BLANCHARD, F. N. - - 1923. The amphibians and reptiles of Dickinson County, Iowa. Univ. - Iowa Stud. Nat. Hist., 10:19-26. - - - * BLATCHLEY, W. S. - - 1891. Notes on the batrachians and reptiles of Vigo County, - Indiana. Jour. Cincinnati Soc. Nat. Hist., 14:22-35 - (from Carr, 1952:467). - - - BOGERT, C. M., and OLIVER, J. A. - - 1945. A preliminary analysis of the herpetofauna of Sonora. Bull. - Amer. Mus. Nat. Hist., 83(6):297-426, 13 figs., 8 pls., - 1 table, 2 maps, March 30. - - - BOULENGER, G. A. - - 1889. Catalogue of the chelonians, rhynchocephalians, and - crocodiles in the British Museum (Natural History). Taylor - and Francis, London, x + 311 pp., 73 figs., 6 pls. - - 1890. The fauna of British India, including Ceylon and Burma. - Reptilia and Batrachia. Taylor and Francis, London, xviii - + 541 pp., 142 figs. - - - BOYER, D. A., and HEINZE, A. A. - - 1934. An annotated list of the amphibians and reptiles of Jefferson - County, Missouri. Trans. Acad. Sci. St. Louis, 28(3):185-202, - 1 fig., April 1. - - - BRATTSTROM, B. H. - - 1958. New records of Cenozoic amphibians and reptiles from - California. Bull. Southern California Acad. Sci., 57(1):5-12, - 2 pls. - - - BRECKENRIDGE, W. J. - - 1944. Reptiles and amphibians of Minnesota. Univ. Minnesota Press, - Minneapolis, xiii + 202 pp., 52 figs., 45 maps. - - 1955. Observations on the life history of the soft-shelled turtle - _Trionyx ferox_, with especial reference to growth. Copeia, - 1955(1):5-9, 4 figs., 3 tables, February 18. - - 1957. A large spiny soft-shelled turtle. Copeia, 1957(3):232, - August 26. - - 1960. A spiny soft-shelled turtle nest study. Herpetologica, - 16(4):284-285, December 30. - - - BRENNAN, L. A. - - 1934. A check list of the amphibians and reptiles of Ellis County, - Kansas. Trans. Kansas Acad. Sci., 37:189-191. - - - BREUKELMAN, J., and SMITH, H. M. - - 1946. Selected records of reptiles and amphibians from Kansas. - Univ. Kansas Publ. Mus. Nat. Hist., 1(5):101-112, August 15. - - - BRIMLEY, C. S. - - 1910. Records of some reptiles and batrachians from the - southeastern United States. Proc. Biol. Soc. Washington, - 23:9-18, March 23. - - - BROCK, V. E. - - 1947. The establishment of _Trionyx sinensis_ in Hawaii. Copeia, - 1947 (2):142, June 30. - - - BROWN, B. C. - - 1950. An annotated check list of the reptiles and amphibians of - Texas. Baylor Univ. Press, Waco, xii + 257 pp. - - - BRUMWELL, M. J. - - 1951. An ecological survey of the Fort Leavenworth Military - Reservation. Amer. Midl. Nat., 45(1):187-231, 6 figs., January. - - - BRYAN, K., and ALBRITTON, C. C., JR. - - 1943. Soil phenomena as evidence of climatic changes. Amer. Jour. - Sci., 241(8):469-490, August. - - - BUNDY, R. E. - - 1951. New locality records of reptiles in New Mexico. Copeia, - 1951(4): 314, December 28. - - - BURT, C. E. - - 1933. Some distributional and ecological records of Kansas - reptiles. Trans. Kansas Acad. Sci., 36:186-208. - - 1935. Further records of the ecology and distribution of amphibians - and reptiles in the middle west. Amer. Midl. Nat., 16(3):311-66, - May. - - - BURT, C. E., and HOYLE, W. L. - - 1934. Additional records of the reptiles of the central prairie - region of the United States. Trans. Kansas Acad. Sci., - 37:193-216. - - - BUTLER, A. W. - - 1894. On the habits of turtles. Proc. Indiana Acad. Sci., 1893, - p. 224, August. - - - CAGLE, F. R. - - 1939. A system of marking turtles for future identification. - Copeia, 1939(3):170-73, 1 fig., September 9. - - 1942. Turtle populations in southern Illinois. Copeia, - 1942(3):155-162, 1 pl., October 8. - - 1942a. Herpetological fauna of Jackson and Union counties, - Illinois. Amer. Midl. Nat., 28(1):164-200, July. - - 1944. Home range, homing behavior, and migration in turtles. Misc. - Publ. Mus. Zool., Univ. Michigan, 61:1-34, 4 figs., 2 pls., - 1 map, November 21. - - 1950. The life history of the slider turtle, _Pseudemys scripta - troostii_ (Holbrook). Ecol. Monog., 20(1):31-54, 18 figs., - January. - - 1954. Two new species of the genus _Graptemys_. Tulane Stud. Zool., - 1(11):167-86, 15 figs., 1 table, August 26. - - - CAGLE, F. R., and CHANEY, A. H. - - 1950. Turtle populations in Louisiana. Amer. Midl. Nat., - 43(2):383-88, 2 figs., March. - - - CAHN, A. R. - - 1929. The herpetology of Waukesha County, Wisconsin. Copeia, 1929 - (170):4-8, April 30. - - 1937. The turtles of Illinois. Illinois Biol. Monog., - 16(1-2):1-218, 31 pls., 20 tables, 20 maps, 15 figs., - August 31. - - - CARR, A. F., JR. - - 1940. A contribution to the herpetology of Florida. Univ. Florida - Publ., Biol. Sci. Ser., 3(1):1-118, January. - - 1952. Handbook of turtles. The turtles of the United States, Canada - and Baja California. Comstock Publ. Assoc., Cornell Univ. - Press, xv + 542 pp., 37 figs., 82 pls., 15 tables, 23 maps. - - - CHANEY, A. H., and SMITH, C. C. - - 1950. Methods for collecting map turtles. Copeia, 1950(4):323-24, - December 22. - - - CLARK, H. W., and SOUTHALL, J. B. - - 1920. Fresh-water turtles: a source of meat supply. Rep't. U. S. - Comm. Fish., 1919, Appendix 7, U. S. Bur. Fish. Doc., - 889:1-20, 8 pls. - - - CLARKE, R. F. - - 1956. Distributional notes on some amphibians and reptiles in - Kansas. Trans. Kansas Acad. Sci., 59:213-19. - - 1958. An ecological study of reptiles and amphibians in Osage - County, Kansas. Emporia St. Res. Stud., 7(1):1-52, 15 figs., - 4 tables, September. - - - COMMITTEE ON HERPETOLOGICAL COMMON NAMES. - - 1956. Common names for North American amphibians and reptiles. - Copeia, 1956(3):172-185, August 29. - - - CONANT, R. - - 1930. Field notes of a collecting trip. Bull. Antivenin Inst. - Amer., 4(3): 60-64, December. - - 1951. The reptiles of Ohio. Second edition (with revisionary - addenda). Amer. Midl. Nat., Univ. Notre Dame Press, - 284 pp., 27 pls., 77 maps. - - 1958. A field guide to reptiles and amphibians of eastern North - America. Houghton Mifflin Co., Boston, xviii + 366 pp., - 62 figs., 40 pls., 248 maps. - - - CONANT, R., and GOIN, C. J. - - 1948. A new subspecies of soft-shelled turtle from the central - United States, with comments on the application of the - name _Amyda_. Occas. Pap. Mus. Zool., Univ. Michigan, - No. 510:1-19, 2 pls. - - - COOK, F. A. - - 1946. Distribution of species of _Amyda_ in Mississippi. Jour. - Mississippi Acad. Sci., 1946, pp. 185-190. - - - COPE, E. D. - - 1894. Note on the above (Trionyches in the Delaware drainage by - C. W. Johnson). Amer. Nat., 28:889, October. - - - CORRINGTON, J. D. - - 1927. Field notes on some amphibians and reptiles at Biloxi, - Mississippi. Copeia, 1927(165):98-102, December 23. - - - COWLES, R. B., and BOGERT, C. M. - - 1936. The herpetology of the Boulder Dam region (Nev., Ariz., - Utah). Herpetologica, 1 (Pt. 2):33-42, December 30. - - - COX, U. O. - - 1894. The climbing habits of the softshell turtle (_Aspidonectes - spinifer_). Science, 23(573):50, January 26. - - - CRENSHAW, J. W., JR., and HOPKINS, M. N., JR. - - - 1955. The relationships of the soft-shelled turtles _Trionyx ferox - ferox_ and _Trionyx ferox aspera_. Copeia, 1955 (1):13-23, - 4 figs., February 18. - - - D'ABREU, E. A. - - 1928. An albino turtle. Jour. Bombay Nat. Hist. Soc., 32(3):608. - - - DARLINGTON, P. J., JR. - - 1957. Zoogeography: The geographical distribution of animals. - John Wiley and Sons, Inc., New York, xiv + 675 pp., 80 figs., - 21 tables, frontispiece. - - - * DAUDIN, F. M. - - 1801. Histoire naturelle, générale et particuliére des Reptiles. - Paris, 2:1-432, 13 pls. (from Loveridge and Williams, 1957:511). - - - DECKERT, R. F. - - 1918. A list of reptiles from Jacksonville, Florida. Copeia, 1918 - (54):30-33, February 17. - - - DE KAY, J. E. - - 1842. Zoology of New-York. Part III. Reptiles and Amphibia. Albany, - vi + 98 pp., 23 pls. - - - DELLINGER, S. C., and BLACK, J. D. - - 1938. Herpetology of Arkansas. Part One. The Reptiles Occas. Pap. - Univ. Arkansas Mus., No. 1:1-47 pp., June 11. - - - DERANIYAGALA, P. E. P. - - 1930. Testudinate evolution. Proc. Zool. Soc. London, 1930, pp. - 1057-70, 3 pls., January 21, 1931. - - 1939. The tetrapod reptiles of Ceylon. Volume 1. Testudinates and - crocodilians. Ceylon Jour. Sci., Columbo Mus. Nat. Hist. Ser., - xxxii + 412 pp., 137 figs., 24 pls., 62 tables. - - - DE ROOIJ, N. - - 1915. The reptiles of the Indo-Australian Archipelago. I. - Lacertilia, Chelonia, Emydosauria. E. J. Brill Ltd., Leiden, - xiv + 384 pp., 132 figs. - - - DE SOLA, C. R., and ABRAMS, F. - - 1933. Testudinata from south-eastern Georgia, including the - Okefinokee swamp. Copeia, 1933(1):10-12, April 3. - - - DICKINSON, W. E. - - 1950. Recent additions to the records of the distribution of the - reptiles in Wisconsin. Trans. Wisconsin Acad. Sci. Arts - Letters, 40(1):71-77, August 15. - - - DILL, W. A. - - 1944. The fishery of the lower Colorado River. California Fish and - Game, 30(3):109-211, 38 figs., 7 tables, July. - - - DORF, E. - - 1959. Climatic changes of the past and present. Contr. Mus. - Paleont., Univ. Michigan, 13(8):181-210, 3 figs., 1 pl., - 7 maps, April 17. - - - DOWLING, H. G. - - 1957. A review of the amphibians and reptiles of Arkansas. Occas. - Pap. Univ. Arkansas Mus., No. 3:1-51, 1 map, July 15. - - - DUELLMAN, W. E., and SCHWARTZ, A. - - 1958. Amphibians and reptiles of southern Florida. Bull. Florida - St. Mus., 3(5):81-324, 28 figs. - - - DUMÉRIL, A. M. C., and BIBRON, G. - - 1835. Erpétologie générale ou histoire naturelle complète des - reptiles. Paris, 2:iv + 682 pp., 12 pls., 2 folding tables. - - - DUNDEE, H. A. - - 1950. _Kinosternon subrubrum hippocrepis_ (Gray) in Oklahoma. - Herpetologica, 6(Pt. 5):138-39, November 20. - - - DUNN, E. R. - - 1931. The herpetological fauna of the Americas. Copeia, - 1931(3):106-119, 6 figs., October 30. - - - DUNSON, W. A. - - 1960. Aquatic respiration in _Trionyx spinifer asper_. - Herpetologica, 16 (4):277-83, 2 figs., December 30. - - - * DUTTA, S. K. - - 1931. Congenital absence of limbs in tortoises of the genera - _Trionyx_ and _Emyda_. Allahabad Univ. Stud., Sci. Sect., - 8(2):1-8 (from Biol. Absts.). - - - EATON, T. H. - - 1945. Herpetological notes from Allegany State Park, New York. - Copeia, 1945(2):115, June 30. - - - EDGREN, R. A. - - 1942. Amphibians and reptiles from Van Buren County, Michigan. - Copeia, 1942(3):180, October 8. - - 1944. Notes on amphibians and reptiles from Wisconsin. Amer. - Midl. Nat., 32(2):495-498, September. - - - EIGENMANN, C. H. - - 1896. Testudinata (of Turkey Lake, Indiana). Proc. Indiana Acad. - Sci., 1895, 5:262-64. - - - ENDSLEY, J. R. - - 1954. An annotated listing of a herpetological collection mainly - from Tennessee. Jour. Tennessee Acad. Sci., 29(1):36-41, - January. - - - EVANS, H. E., and ROECKER, R. M. - - 1951. Notes on the herpetology of Ontario, Canada. Herpetologica, - 7(Pt. 2):69-71, June 5. - - - EVERMANN, B. W., and CLARK, H. W. - - 1920. Lake Maxinkuckee: A physical and biological survey. Vol. 1. - Dep't. Conserv. St. Indiana, Publ. No. 7, 660 pp., 23 figs., - 8 pls., 36 color pls., frontispiece, 1 folding map. Contains - "The turtles and batrachians of the Lake Maxinkuckee region," - Proc. Indiana Acad. Sci., 1917 (1916), pp. 472-518, with - minor changes. - - - FITZINGER, L. - - 1835. Entwurf einer systematischen Anordnung der Schildkröten nach - den Grundsätzen der natürlichen Methode. Ann. Wiener Mus. - Naturg., 1(1):103-128. - - 1843. Systema reptilium. Fasc. I. Ambyglossae. Vindobonae, - vi + 106 pp. - - - FLOWER, S. S. - - 1933. Notes on recent reptiles and amphibians. Proc. Zool. Soc. - London, 1933, pp. 735-851, 1 fig., 1 map, September 20. - - - FORCE, E. R. - - 1930. The amphibians and reptiles of Tulsa County, Oklahoma, and - vicinity. Copeia, 1930(2):25-39, June 30. - - - FOWLER, H. W. - - 1907. The amphibians and reptiles of New Jersey. Ann. Rep't. - New Jersey St. Museum, 1906, 2:23-250. - - - FUNKHOUSER, W. D. - - 1925. Wild life in Kentucky. Kentucky Geol. Surv., 16(ser. 6):xiv + - 385, 89 figs., frontispiece. - - - GADOW, H. - - 1909. Amphibia and reptiles. Macmillan and Co., Ltd., London, - xiii + 668 pp., 181 figs. - - - GAGE, S. H. - - 1884. Pharyngeal respiration in the soft-shelled turtle - (_Aspidonectes spinifer_). Proc. Amer. Assoc. Adv. Sci., - 1883, 32:316-18. - - - GAGE, S. H., and GAGE, S. P. - - 1886. Aquatic respiration in soft-shelled turtles: a contribution - to the physiology of respiration in vertebrates. Amer. Nat., - 20:233-236, March. - - - GALBREATH, E. C. - - 1948. Pliocene and Pleistocene records of fossil turtles from - western Kansas and Oklahoma. Univ. Kansas Publ. Mus. Nat. - Hist., 1(17):283-284, August 16. - - - GEHLBACH, F. R., and COLLETTE, B. B. - - 1959. Distributional and biological notes on the Nebraska - herpetofauna. Herpetologica, 15(Pt. 3):141-143, September 10. - - - GENTRY, G. - - 1941. Herpetological collections from counties in the vicinity of - the Obey River drainage of Tennessee. Jour. Tennessee Acad. - Sci., 16(3):329-332, July. - - - GEOFFROY SAINT-HILAIRE, É. - - * 1809. Mémoire sur les tortues molles. Nouv. Bull. Sci. Philom., - Paris, 1(22):363-67, July (from Stejneger, 1944:27, and - Loveridge and Williams, 1957:515). - - 1809a. Mémoire sur les tortues molles, nouveau genre sous le nom de - _Trionyx_, et sur la formation des carapaces. Ann. Mus. Hist. - Nat., Paris, 14:1-20 pp., 5 pls., August. - - - * GILMORE, C. W. - - 1946. Reptilian fauna of the North Horn Formation of central Utah. - Prof. Pap. U. S. Geol. Surv., 210-C:28-53 (from Biol. Absts.). - - - GLOYD, H. K. - - 1928. The amphibians and reptiles of Franklin County, Kansas. - Trans. Kansas Acad. Sci., 31:115-141. - - - GOFF, D. S., and GOFF, C. C. - - 1935. On the incubation of a clutch of eggs of _Amyda ferox_ - (Schneider). Copeia, 1935(3):156, October 15. - - - GOIN, C. J. - - 1948. The occurrence of _Amyda spinifer aspera_ in Florida. Copeia, - 1948 (4):304, December 31. - - - GOLDSMITH, W. M. - - 1945. Notes on the egg laying habits of the softshell turtles. - Proc. Iowa Acad. Sci., 1944, 51:447-49, December. - - - GRAY, J. E. - - 1844. Catalogue of the tortoises, crocodiles, and amphisbaenians in - the collection of the British Museum. London, viii + 80 pp. - - 1855. Catalogue of shield reptiles in the collection of the British - Museum. Part I. Testudinata (Tortoises). London, 79 pp., - 42 pls. - - 1864. Revision of the species of Trionychidae found in Asia and - Africa, with descriptions of some new species. Proc. Zool. - Soc. London, 1864, pp. 76-98, 21 figs., February 23. - - 1869. Notes on the families and genera of tortoises (Testudinata) - and on the characters afforded by the study of their skulls. - Proc. Zool. Soc. London, 1869, pp. 165-225, 20 figs., 1 pl., - March 11. - - 1870. Supplement to the catalogue of shield reptiles in the - collection of the British Museum. Part I. Testudinata - (Tortoises). With figures of skulls of 36 genera. London, - 120 pp., 40 figs. - - - GREEN, N. B. - - 1937. The amphibians and reptiles of Randolph County, West - Virginia. Herpetologica, 1(Pt. 4):113-16, November 16. - - - GUIDRY, E. V. - - 1953. Herpetological notes from southeastern Texas. Herpetologica, - 9 (Pt. 1):49-56, June 1. - - - GUNNING, G. E., and LEWIS, W. M. - - 1957. An electrical shocker for the collection of amphibians and - reptiles in the aquatic environment. Copeia, 1957 (1):52, - April 5. - - - HALL, H. H., and SMITH, H. M. - - 1947. Selected records of reptiles and amphibians from southeastern - Kansas. Trans. Kansas Acad. Sci., 49(4):447-54. - - - HAMILTON, W. J., JR. - - 1947. Egg laying of _Trionyx ferox_. Copeia, 1947(3):209, September - 12. - - - HARDY, R., and LAMOREAUX, L. - - 1945. Emory's turtle in the Virgin River drainage of northwestern - Arizona. Copeia, 1945(3):168, October 15. - - - HARPER, F. - - 1926. Tales of the Okefinokee. Amer. Speech, 1(8):407-20, May. - - 1940. Some works of Bartram, Daudin, Latreille, and Sonnini, and - their bearing upon North American herpetological - nomenclature. Amer. Midl. Nat., 23(3):692-723, 1 fig., May. - - - HARWOOD, P. D. - - 1932. The helminths parasitic in the Amphibia and Reptilia of - Houston, Texas and vicinity. Proc. U. S. Nat. Mus., - 81(2940):1-71, 5 pls. - - - HAY, O. P. - - 1892. The batrachians and reptiles of the state of Indiana. Ann. - Rep't Indiana Dep't Geol. Nat. Res., 17:1-204 pp., 3 pls. - - 1908. The fossil turtles of North America. Publ. Carnegie Inst. - Washington, 75:iv + 568, 704 figs., 113 pls. - - 1910. Descriptions of eight new species of fossil turtles from west - of the one-hundredth meridian. Proc. U. S. Nat. Mus., - 38(1747):307-26, 23 figs., 3 pls., June 29. - - - HEDRICK, R. M., and HOLMES, J. C. - - 1956. Additional Minnesota herpetological notes. Flicker, - 28(3):123-26, September. - - - HEMMING, R. (editor). - - 1956. Opinion 417. Ops. Decs. Internat. Comm. Zool. Nomencl., - 14(1):1-42. - - 1957. Opinion 447. Ops. Decs. Internat. Comm. Zool. Nomencl., - 15(12):211-224. - - - HENNING, W. L. - - 1938. Amphibians and reptiles of a 2,200-acre tract in central - Missouri. Copeia, 1938(2):91-92, June 30. - - - HERALD, E. S. - - 1949. Effects of DDT-oil solutions upon amphibians and reptiles. - Herpetologica, 5(Pt. 6):117-20, December 15. - - - HIBBARD, C. W. - - 1936. The amphibians and reptiles of Mammoth Cave National Park - proposed. Trans. Kansas Acad., Sci., 39:277-81. - - - HOBBS, W. H. - - 1950. The Pleistocene history of the Mississippi River. Science, N. - S., 111:260-62, 2 figs., March 10. - - - HOFFMAN, C. K. - - 1890. Reptilian. I. Schildkröten. _In_ Bronn's Klassen und - Ordnungen des Thier-Reichs. Leipzig, 6(3):1-442, 48 pls. - - - HOLLAND, W. C. - - 1944. Physiographic divisions of the Quarternary lowlands of - Louisiana. Proc. Louisiana Acad. Sci., 8:11-24, 1 fig., - December. - - - HUBBS, C. - - 1957. Distributional patterns of Texas fresh-water fishes. - So'western Nat., 2(2-3):89-104, 2 figs., December 27. - - - HUDSON, G. E. - - 1942. The amphibians and reptiles of Nebraska. Nebraska Conserv. - Bull., No. 24:1-145, 20 pls., 32 maps, June. - - - HUGHES, R. C., BAKER, J. R., and DAWSON, C. B. - - 1941. The tapeworms of reptiles. Part II. Host catalogue. Wasmann - Collector, 4(3):97-104, April. - - - HUGHES, R. C., HIGGINBOTHAM, J. W., and CLARY, J. W. - - 1941. The trematodes of reptiles. Part II. Host catalogue. Proc. - Oklahoma Acad. Sci., 1940, 21:35-43. - - - HUMMEL, K. - - 1929. Die fossilen weichschildkröten (Trionychia). Eine - morphologisch-systematische und stammesgeschichtliche - studie. Geol. und Paläont. Abh. N. F., 16(5):357-487, 34 - figs. Abstract by K. Staesche in Neu. Jahrb. Min., Geol. und - Paläont., Referate III, 1929, pp. 768-72. - - - HURTER, J. - - 1911. Herpetology of Missouri. Trans. Acad. Sci. St. Louis, - 20(5):59-274, 7 pls., July 28. - - - HURTER, J., and STRECKER, J. K. - - 1909. Amphibians and reptiles of Arkansas. Trans. Acad. Sci. St. - Louis, 18(2):11-27, May 14. - - - JOHNSON, C. W. - - 1894. Trionyches in the Delaware drainage. Amer. Nat., 28:889, - October. - - - KARLSTROM, E. L. - - 1957. The use of CO^{60} as a tag for recovering amphibians in the - field. Ecology, 38(2):187-195, 6 figs., 1 table, April. - - - KELLOGG, R. - - 1929. The habits and economic importance of alligators. U. S. - Dep't. Agric., Tech. Bull. 147:1-36, December. - - - KNEPTON, J. C., JR. - - 1956. County records of Testudinata collected in Georgia. Jour. - Tennessee Acad. Sci., 31(4):322-24, October. - - - LACÉPÈDE, B. G. E. - - 1788. Histoire naturelle des quadrupèdes ovipares et des serpens. - Volume I. Paris, 17 pp., 1 folding table, 651 pp., 1 folding - table, 41 pls. - - - LAGLER, K. F. - - 1943. Food habits and economic relations of the turtles of Michigan - with special reference to fish management. Amer. Midl. Nat., - 29(2): 257-312, 9 figs., 9 tables, March. - - 1943a. Methods of collecting fresh-water turtles. Copeia, - 1943(1):21-25 1 fig., March 31. - - 1954. Michigan turtles. Reprint from Michigan Conserv., 23(3):no - page numbers, May-June. - - - LANE, H. H. - - 1910. A paired entoplastron in _Trionyx_ and its significance. - Proc. Indiana Acad. Sci., 1909, pp. 345-50. - - - LEGLER, J. M. - - 1955. Observations on the sexual behavior of captive turtles. - Lloydia, 18(2):95-99, June. - - - LESUEUR, C. A. - - 1827. Note sur deux especes de tortues du genre _Trionyx_ Gffr. St. - H. Mém. Mus. Hist. Nat. Paris, 15:257-68, 2 pls. - - - LINSDALE, J. M. - - 1927. Amphibians and reptiles of Doniphan County, Kansas. Copeia, - 1927(164):75-81, July-September. - - 1940. Amphibians and reptiles in Nevada. Proc. Amer. Acad. Arts - Sci., 73(8): 197-257, 29 figs., May. - - - LINSDALE, J. M., and GRESSITT, J. L. - - 1937. Soft-shelled turtles in the Colorado River basin. Copeia, - 1937 (4):222-225, 3 figs., December 31. - - - LITTLE, E. L., and KELLER, J. G. - - 1937. Amphibians and reptiles of the Jornada Experimental Range, - New Mexico. Copeia, 1937(4):216-22, December 31. - - - LÖDING, H. P. - - 1922. A preliminary catalogue of Alabama amphibians and reptiles. - Geol. Surv. Alabama, Alabama Mus. Nat. Hist., No. 5:1-59 - pp., September. - - - LOGIER, E. B. S., and TONER, G. C. - - 1955. Check-list of the amphibians and reptiles of Canada and - Alaska. Contr. Roy. Ontario Mus. Zool. Palaeont., No. 41:v + - 88 pp., 77 maps, August 31. - - - LOVERIDGE, A., and WILLIAMS, E. E. - - 1957. Revision of the African tortoises and turtles of the suborder - Cryptodira. Bull. Mus. Comp. Zool., 115(6):163-557, 62 - figs., 18 pls., February. - - - * MANSUETI, R., and WALLACE, D. H. - - 1960. Notes on the soft-shell turtle (_Trionyx_) in Maryland - waters. Chesapeake Sci., 1(1):71-72. - - - MARR, J. C. - - 1944. Notes on amphibians and reptiles from the central United - States. Amer. Midl. Nat., 32(2):478-90, September. - - - MARTIN, P. S., and HARRELL, B. E. - - 1957. The Pleistocene history of temperate biotas in Mexico and - eastern United States. Ecology, 38(3):468-80, 15 figs., 2 - tables, July. - - - MASLIN, T. P. - - 1959. An annotated check list of the amphibians and reptiles of - Colorado. Univ. Colorado Stud., Ser. Biol., 6:vi + 98 pp., - November. - - - MATTOX, N. T. - - 1936. Annular rings in the long bones of turtles and their - correlation with size. Trans. Illinois St. Acad. Sci., 1935, - 28(2):255-56, March. - - - MEEK, S. E. - - 1904. The fresh-water fishes of Mexico north of the Isthmus of - Tehuantepec. Field Columbian Mus. Publ. 93, Zool. Ser., - 5:lxiii + 252, 72 figs., 17 pls., 1 map, August. - - - * MERTENS, R. - - 1928. Über die einwirkung der kulturlandschaft auf die verbreitung - der amphibien und reptilien. Zool. Garten Leipzig, N. S., - 1(Pt. 5-6): 195-203 (from Biol. Absts., and Stejneger, - 1944:47). - - - MERTENS, R., and WERMUTH, H. - - 1955. Die rezenten schildkröten, krokodile und brückenechsen. Zool. - Jahrb., 83(5):323-440, October 31. - - - MILLER, R. R. - - 1946. The probable origin of the soft-shelled turtle in the - Colorado River basin. Copeia, 1946(1):46, April 30. - - 1959. Origin and affinities of the fresh-water fish fauna of - western North America. _In_ Zoogeography, edit. C. L. Hubbs. - Amer. Assoc. Adv. Sci., Publ. No. 51, Washington, pp. - 187-222, 19 figs., 2 tables, January 16. - - - MINTON, S. A., JR. - - 1944. Introduction to the study of the reptiles of Indiana. Amer. - Midl. Nat., 32(2):438-477, September. - - 1959. Observations on amphibians and reptiles of the Big Bend - region of Texas. So'western Nat., 1958, 3(1-4):28-54, 6 - tables, 1 map, May 29. - - - MITSUKURI, K. - - 1905. The cultivation of marine and fresh-water animals in Japan. - The snapping turtle, or soft-shell tortoise, "suppon." Bull. - U. S. Bur. Fish., 24:60-266, 2 figs., 1 pl. - - - MITTLEMAN, M. B. - - 1944. The status of _Testudo terrapin_ Schoepf. Copeia, - 1944(4):245-250, December 26. - - - * MOHR, J. C. - - 1929. A case of partial albinism in _Trionyx cartilagineus_ - (Bodd.). Misc. Zool. Sumatrana, 40:1-2 (from Biol. Absts.). - - - MOORE, G. A., and RIGNEY, C. C. - - 1942. Notes on the herpetology of Payne County, Oklahoma. Proc. - Oklahoma Acad. Sci., 22:77-80. - - - MÜLLER, F. - - 1878. Katalog der im museum und universitätskabinet zu Basel - aufgestellten amphibien und reptilien nebst anmerkungen. - Verh. der Natur. Ges. Basel, 6:557-709, 3 pls. - - - MULLER, J. F. - - 1921. Notes on the habits of the soft-shell turtle, _Amyda mutica_. - Amer. Midl. Nat., 7(6):180-83, November. - - - MULLERRIED, F. K. G. - - 1943. Fosiles raros de Mexico III.--Una tortuga fosil del estado de - Chiapas. An. Inst. Biol. Mexico, 14(2):623-24. - - - MYERS, G. S. - - - 1927. Notes on Indiana amphibians and reptiles. Proc. Indiana Acad. - Sci., 1926, 36:337-40. - - - NECKER, W. L. - - - 1939. Records of amphibians and reptiles of the Chicago region, - 1935-1938. Bull. Chicago Acad. Sci., 6(1):1-10. - - - NEILL, W. T. - - - 1951. Taxonomy of North American soft-shelled turtles, genus - _Amyda_. Publ. Res. Div. Ross Allen's Rept. Inst., - 1(2):7-24, 1 fig., January 31. - - 1951a. Notes on the role of crawfishes in the ecology of reptiles, - amphibians, and fishes. Ecology, 32(4):764-66, October. - - 1958. The occurrence of amphibians and reptiles in saltwater areas, - and a bibliography. Bull. Marine Sci. Gulf and Caribbean, - 8(1):97 pp., March. - - - NETTING, M. G. - - - 1944. The spineless soft-shelled turtle, _Amyda mutica_ (Le Sueur), - in Pennsylvania. Ann. Carnegie Mus., 30:85-88. - - - NEWMAN, H. H. - - - 1906. The habits of certain tortoises. Jour. Comp. Neurol. - Psychol., 16(2):126-52. - - - NIELSEN, A. - - - 1951. Is dorsoventral flattening of the body an adaptation to - torrential life? Proc. Internat'l. Assoc. Limnology, - 11:264-67. - - - NIXON, C. W., and SMITH, H. M. - - - 1949. The occurrence of kyphosis in turtles. Turtox News, - 27(1):28-29, 3 figs., January. - - - NOLAND, W. E. - - - 1951. The hydrography, fish, and turtle population of Lake Wingra. - Trans. Wisconsin Acad. Sci. Arts Letters, 40(2):5-58, 1 map, - April 27. - - - NOPCSA, F. B. - - - 1926. Heredity and evolution. Proc. Zool. Soc. London, 1926, pp. - 633-65, 9 figs. - - - OKADA, Y. - - - * 1930. Notes on the herpetology of the Chichijima, one of the - Bonin Islands. Bull. Biogeog. Soc. Japan, 1(3):187-91 - (Japanese), pp. 193-94 (English summary) (from Biol. - Absts.). - - 1938. A catalogue of vertebrates of Japan. Maruzen Co., Ltd., - Tokyo, iv + 412 pp. - - - * OKEN, L. - - - 1816. Lehrbuch Zoologie (Naturgeschichte III, 2). Leipzig, xvi + - 1270 pp. (from Conant and Goin, 1948:18). - - - OLIVER, J. A. - - - 1955. The natural history of North American amphibians and - reptiles. Van Nostrand Co., Inc., Princeton, New Jersey, ix - + 359 pp., 74 figs., 15 tables, 12 pls. - - - OLIVER, J. A., and SHAW, C. E. - - - 1953. The amphibians and reptiles of the Hawaiian Islands. - Zoologica, 38(5):65-95, 19 figs. - - - OLSON, R. E. - - - 1959. Notes on some Texas herptiles. Herpetologica, 15(Pt. 1):48, - February 25. - - - ORTENBURGER, A. I. - - - 1927. A report on the amphibians and reptiles of Oklahoma. Proc. - Oklahoma Acad. Sci., 1926, 6(Pt. 1):89-100. - - - ORTENBURGER, A. I., and FREEMAN, B. - - - 1930. Notes on some reptiles and amphibians from western Oklahoma. - Publ. Univ. Oklahoma Biol. Surv., 2(4):175-88, 2 maps. - - - OVER, W. H. - - - 1943. Amphibians and reptiles of South Dakota. Nat. Hist. Stud., - Univ. So. Dakota, 6:1-31, 20 figs., July. - - - PARKER, M. V. - - - 1937. Some amphibians and reptiles from Reelfoot Lake. Jour. - Tennessee Acad. Sci., 12(1):60-86, 18 figs., January. - - 1939. The amphibians and reptiles of Reelfoot Lake and vicinity, - with a key for the separation of species and subspecies. - Jour. Tennessee Acad. Sci., 14(1):72-101, 14 figs., January. - - 1948. A contribution to the herpetology of western Tennessee. Jour. - Tennessee Acad. Sci., 23(1):20-30, January. - - - PARSONS, T. S. - - - 1958. The choanal papillae of the Cheloniidae. Breviora, 85:1-5, 2 - pls., January 31. - - 1960. The structure of the choanae of the Emydinae (Testudines, - Testudinidae). Bull. Mus. Comp. Zool., 123(4):113-127, 4 - figs., September. - - - PENN, G. H. - - - 1950. Utilization of crawfishes by cold-blooded vertebrates in the - eastern United States. Amer. Midl. Nat., 44(3):643-58, 3 - figs., 4 tables, November. - - - PENNANT, T. - - - 1772. An account of two new tortoises: in a letter to Matthew Maty, - M. D. Sci. R. S. Philos. Trans. London, 1771, 61:266-73, 1 - pl. - - - PETERS, J. A. - - - 1942. Reptiles and amphibians of Cumberland County, Illinois. - Copeia, 1942(3):182-83, October 8. - - - PICKENS, A. L. - - - 1927. Reptiles of upper South Carolina. Copeia, 1927(165):110-13, - December 23. - - - PIMENTEL, R. A. - - - 1959. On the analysis of biological data. Turtox News, - 37(4):98-101, 1 fig., April. - - - POPE, C. H. - - - 1935. The reptiles of China. Natural history of central Asia. Vol. - X. Amer. Mus. Nat. Hist., lii + 604 pp., 78 figs., 64 - tables, 27 pls. - - 1949. Turtles of the United States and Canada. A. A. Knopf, New - York, 3rd printing, xviii + 343 + v pp., 99 figs., - September. - - - POPE, T. E. B. - - - 1930. Wisconsin herpetological notes. Trans. Wisconsin Acad. Sci. - Arts Letters, 25:273-84. - - - POPE, T. E. B., and DICKINSON, W. E. - - - 1928. The amphibians and reptiles of Wisconsin. Bull. Public Mus. - City Milwaukee, 8(1):1-138, 28 figs., 21 pls., April 3. - - - PROCTOR, V. W. - - - 1958. The growth of Basicladia on turtles. Ecology, 39(4):634-45, 3 - figs., October. - - - RAFINESQUE, C. S. - - - 1832. Description of two new genera of softshell turtles of North - America. Atlantic Jour. and Friend of Knowledge, - Philadelphia, 1(2):64-65, Summer. - - - RISLEY, P. L. - - - 1933. Observations on the natural history of the common musk - turtle, _Sternotherus odoratus_ (Latreille). Pap. Michigan - Acad. Sci. Arts Letters, 1932, 17:685-711, 2 figs., 1 table. - - - RIVERS, J. J. - - - 1889. Description of a new turtle from the Sacramento River, - belonging to the family of Trionychidae. Proc. California - Acad. Sci., 2nd Ser., 2:233-36, December 20. - - - RHOADES, S. N. - - - 1895. Contributions to the zoology of Tennessee. No. 1. Reptiles - and batrachians. Proc. Acad. Nat. Sci. Philadelphia, - 47:376-407. - - - ROMER, A. S. - - - 1945. Vertebrate paleontology. Univ. Chicago Press, 2nd Ed. (5th - printing, 1953), x + 687 pp., 377 figs., 4 tables. - - 1956. Osteology of the reptiles. Univ. Chicago Press, xxi + 772 - pp., 248 figs. - - - RUSSELL, L. S. - - - 1929. Paleocene vertebrates from Alberta. Amer. Jour. Sci., - 17(98):162-178, 5 figs., February. - - 1930. A new species of _Aspideretes_ from the Paskapoo Formation of - Alberta. Amer. Jour. Sci., 20(115):27-32, 3 figs., July. - - 1934. Fossil turtles from Saskatchewan and Alberta. Trans. Roy. - Soc. Canada, 28:101-11, 6 pls., 1 table, May. - - - RUTHVEN, A. G., THOMPSON, C., and THOMPSON, H. - - - 1912. The herpetology of Michigan. Michigan Geol. Biol. Serv., - Publ. 10, Biol. Ser. 3, 161 pp., 55 figs., 16 pls. - - - SCHMIDT, K. P. - - - 1924. Emory's soft-shelled turtle in Arizona. Copeia, 1924(131):64, - June 30. - - 1945. A new turtle from the Paleocene of Colorado. Fieldiana Geol., - 10(1):1-4, 1 fig., September 19. - - 1946. On the zoogeography of the Holarctic Region. Copeia, 1946 - (3):144-152, 1 map, October 20. - - 1953. A check list of North American amphibians and reptiles. Sixth - edition. Amer. Soc. Ichth. Herp., Univ. Chicago Press, viii - + 280 pp. - - - SCHMIDT, K. P., and INGER, R. F. - - - 1957. Living reptiles of the world. Hanover House, Garden City, New - York, 287 pp., 266 illus. - - - SCHMIDT, K. P., and NECKER, W. L. - - - 1935. Amphibians and reptiles of the Chicago region. Bull. Chicago - Acad. Sci., 5(4):57-77. - - - SCHMIDT, K. P., and OWENS, D. W. - - - 1944. Amphibians and reptiles of northern Coahuila, Mexico. Zool. - Ser. Field Mus. Nat. Hist., 29(6):97-115, February 23. - - - * SCHNEIDER, J. G. - - - 1783. Allgemeine Naturgeschichte der Schildkröten, nebst einem - system. Verzeichnisse der einzelnen arten. Leipzig, "2 - Kpftaf. (wovon 1 illum.) gr. 8" (from Engelmann, W., 1846, - Bibliotheca Historico-naturalis. 1700-1846, p. 422). - - - SCHOEPFF, I. D. - - - 1795. The Historia Testudinum iconibus illustrata. Fasc. 5. - Erlangen, Plag. L-O (32 pp.), 6 pls. - - - SCHWARTZ, A. - - - 1956. The relationships and nomenclature of the soft-shelled - turtles (genus _Trionyx_) of the southeastern United States. - Charleston Mus. Leaflet, 26:1-21, 1 fig., 2 maps, 3 pls., - May. - - - * SCHWEIGGER, A. F. - - - 1812. Monographiae cheloniorum. Königsberger Arch. Naturwiss. - Math., 1:271-368, 406-458 (from Loveridge and Williams, - 1957:533). - - - SHIELDS, L. M., and LINDEBORG, R. G. - - - 1956. Records of the spineless soft-shelled turtle and the snapping - turtle from New Mexico. Copeia, 1956(2):120-21, May 29. - - - SHOCKLEY, C. H. - - - 1949. Fish and invertebrate populations of an Indiana bass stream. - Invest. Indiana Lakes Streams, 3(5):247-70, 4 figs., 4 - tables. - - - SHOUP, C. S., PEYTON, J. H., and GENTRY, G. - - - 1941. A limited biological survey of the Obey River and adjacent - streams in Tennessee. Jour. Tennessee Acad. Sci., - 16(1):48-76, 9 tables, January. - - - SIEBENROCK, F. - - - 1902. Zur systematik der schildkrötenfamilie Trionychidae Bell, - nebst der beschreibung einer neuen _Cyclanorbis_-art. - Sitzungsb. Akad. Wiss. Wien, 91(1):807-46, 18 figs., - October. - - 1909. Synopsis der rezenten schildkröten, mit berücksichtigung der - in historischer zeit ausgestorbenen arten. Zool. Jahrb., - Suppl. 10, Pt. 3, pp. 427-618. - - 1924. Die nearktischen Trionychidae. Verh. Zool.-Bot. Ges. Wien, - 1923, 73:180-94. - - - SIMKINS, C. S. - - - 1925. Origin of the germ cells in _Trionyx_. Amer. Jour. Anat., - 36(2): 185-213, 4 pls., November 15. - - - SIMPSON, G. G. - - - 1943. Turtles and the origin of the fauna of Latin America. Amer. - Jour. Sci., 241(7):413-29, July. - - - SMITH, C. E. - - - 1958. Natural History of Thomas County, Nebraska. Privately - published, 99 pp. - - - SMITH, H. M. - - - 1947. Kyphosis and other variations in soft-shelled turtles. Univ. - Kansas Publ. Mus. Nat. Hist., 1(6):117-24, 1 table, July 7. - - 1956. Handbook of amphibians and reptiles of Kansas. Misc. Publ. - Univ. Kansas Mus. Nat. Hist., 2nd ed., No. 9:1-356, 253 - figs., April 20. - - - SMITH, H. M., and JAMES, L. F. - - - 1958. Taxonomic significance of cloacal bursae in turtles. Trans. - Kansas Acad. Sci., 61(1):86-98. - - - SMITH, H. M., NIXON, C. M., and MINTON, S. A., JR. - - - 1949. Observations on constancy of color and pattern in - soft-shelled turtles. Trans. Kansas Acad. Sci., 56(1):92-98, - 3 figs. - - - SMITH, H. M., and TAYLOR, E. H. - - - 1950. An annotated checklist and key to the reptiles of Mexico - exclusive of the snakes. Bull. U. S. Nat. Mus., 199:v + 253. - - - SMITH, M. A. - - - 1930. The Reptilia and Amphibia of the Malay peninsula. A - supplement to G. A. Boulenger's Reptilia and Batrachia, - 1912. Bull. Raffles Mus., 3:xviii + 149 pp., 13 figs., - April. - - 1931. The fauna of British India including Ceylon and Burma. - Reptilia and Amphibia. Vol. I.--Loricata, Testudines. Taylor - and Francis, London, xxviii + 185 pp., 2 pls., 42 figs., 1 - map (frontispiece), March. - - - SMITH, P. W. - - - 1947. The reptiles and amphibians of eastern central Illinois. - Bull. Chicago Acad. Sci., 8(2):21-40. - - - SMITH, P. W., and LIST, J. C. - - - 1955. Notes on Mississippi amphibians and reptiles. Amer. Midl. - Nat., 53(1):115-25, January. - - - SMITH, P. W., and MINTON, S. A., JR. - - - 1957. A distributional summary of the herpetofauna of Indiana and - Illinois. Amer. Midl. Nat., 58(2):341-51, 13 figs. - - - SNEDECOR, G. W. - - - 1956. Statistical methods. Iowa St. College Press, Ames, Iowa, 5th - ed., xiii + 534 pp. - - - STEBBINS, R. C. - - - 1954. Amphibians and reptiles of western North America. McGraw-Hill - Book Co., New York, vii + 528 pp., 104 pls., 52 figs. - - - STEIN, H. A. - - - 1954. Additional records of amphibians and reptiles in southern - Illinois. Amer. Midl. Nat., 51(1):311-12. - - - STEJNEGER, L. - - - 1907. Herpetology of Japan and adjacent territory. Bull. U. S. Nat. - Mus., 58:xx + 577 pp., 409 figs., 35 pls. - - 1944. Notes on the American soft-shell turtles, with special - reference to _Amyda agassizii_. Bull. Mus. Comp. Zool., - 94(1):1-75 pp., 30 pls., 10 tables, May. - - - STEJNEGER, L., and BARBOUR, T. - - - 1917. A check list of North American amphibians and reptiles. - Harvard Univ. Press, Cambridge, Mass., 1st ed., iv + 125 - pp. - - 1923. A check list of North American amphibians and reptiles. - Harvard Univ. Press, Cambridge, Mass., 2d ed., x + 171 pp. - - 1933. A check list of North American amphibians and reptiles. - Harvard Univ. Press, Cambridge, Mass., 3rd ed., xiv + 185 - pp. - - 1939. A check list of North American amphibians and reptiles. - Harvard Univ. Press, Cambridge, Mass., 4th ed., xvi + 207 - pp. - - 1943. A check list of North American amphibians and reptiles. Fifth - edition. Bull. Mus. Comp. Zool., 93(1):xix + 260 pp. - - - STERNBERG, C. M. - - - 1926. Notes on the Edmonton Formation of Alberta. Canadian Field - Nat., 40(5):102-04, May. - - - STILLE, W. T., and EDGREN, R. A., JR. - - - 1948. New records for amphibians and reptiles in the Chicago area, - 1939-1947. Bull. Chicago Acad. Sci., 8(7):195-202. - - - STOCKWELL, G. A. - - - 1878. On some peculiarities in the anatomy of soft-shelled turtles. - The Zoologist, 3rd Ser., 2(23):401-07, November. - - - STONE, W. - - - 1906. Notes on reptiles and batrachians of Pennsylvania, New Jersey - and Delaware. Amer. Nat., 40(471):159-70, March. - - - STRECKER, J. K. - - - 1909. Notes on the herpetology of Burnet County, Texas. Bull. - Baylor Univ., 12(1):1-9, January. - - 1915. Reptiles and amphibians of Texas. Bull. Baylor Univ., - 18(4):1-82, August. - - 1924. Notes on the herpetology of Hot Springs, Arkansas. Bull. - Baylor Univ., 27(3):29-47, September. - - 1926. A list of reptiles and amphibians collected by Louis Garni in - the vicinity of Boerne, Texas. Contr. Baylor Univ. Mus., No. - 6:1-9. - - 1926a. Notes on the herpetology of the east Texas timber belt. 2. - Henderson County amphibians and reptiles. Contr. Baylor - Univ. Mus., 7:3-7, July 15. - - 1927. Observations on the food habits of Texas amphibians and - reptiles. Copeia, 1927(162):6-9, January-March. - - 1928. Occurrence of the spotted night snake (Hypsiglena - ochrorhynchus Cope) in Central Texas, with other Bosque - County herpetological notes. Contr. Baylor Univ. Mus., - 15:1-6, July 10. - - 1935. Notes on the zoology of Texas from the unpublished - manuscripts of John Kern Strecker (assembled and edited by - Walter J. Williams). Bull. Baylor Univ., 38(3):vii + 69 pp. - - - STRECKER, J. K., and FRIERSON, L. S., JR. - - - 1926. The herpetology of Caddo and De Soto Parishes, Louisiana. - Contr. Baylor Univ. Mus., 5:3-10, May 15. - - - STRECKER, J. K., and WILLIAMS, W. J. - - - 1927. Herpetological records from the vicinity of San Marcos, - Texas, with distributional data on the amphibians and - reptiles of the Edwards Plateau region and central Texas. - Contr. Baylor Univ. Mus., 12:1-16, December. - - - STUNKARD, H. W. - - - 1930. Morphology and relationships of the trematode _Opisthoporus - aspidonectes_ (MacCallum, 1917) Fukui, 1929. Trans. Amer. - Micros. Soc., 49(3):210-19, 1 pl., July. - - - SURFACE, H. A. - - - 1908. First report on the economic features of turtles of - Pennsylvania. Zool. Bull. Div. Zool. Pennsylvania St. Dep't. - Agric., 6(4-5):105-96. - - - SWANSON, P. L. - - - 1939. Herpetological notes from Indiana. Amer. Midl. Nat., - 22(3):684-95, November. - - 1952. The reptiles of Venango County, Pennsylvania. Amer. Midl. - Nat., 47(1):161-82, 1 fig., January. - - - TAYLOR, E. H. - - - 1920. Philippine turtles. Philippine Jour. Sci., 16(2):111-44, 7 - pls. - - 1933. Observations on the courtship of turtles. Univ. Kansas Sci. - Bull., 21(9):269-71, March 15. - - 1935. Arkansas amphibians and reptiles in the Kansas University - Museum. Univ. Kansas Sci. Bull., 22(10):207-18, April 15. - - - TELFORD, S. R., JR. - - - 1952. A herpetological survey in the vicinity of Lake Shipp, Polk - County, Florida. Quart. Jour. Florida Acad. Sci., - 15(3):175-85. - - - TIHEN, J. A., and SPRAGUE, J. M. - - - 1939. Amphibians, reptiles, and mammals of the Meade County State - Park. Trans. Kansas Acad. Sci., 42:499-512, 5 figs., 3 pls. - - - TINKLE, D. W. - - - 1958. The systematics and ecology of the _Sternothaerus carinatus_ - complex (Testudinata, Chelydridae). Tulane Stud. Zool., - 6(1):1-56, 57 figs., March 31. - - - TROWBRIDGE, A. H. - - - 1937. Ecological observations on amphibians and reptiles collected - in southeastern Oklahoma during the summer of 1934. Amer. - Midl. Nat., 18(2):285-303, 1 fig., March. - - - TRUE, F. W. - - - 1893. Useful aquatic reptiles and batrachians of the United States. - _In_ The fisheries and fishery industries of the United - States by G. B. Goode, Sect. I, Part II, pp. 137-162. - - - VAN DENBURGH, J. - - - 1917. Concerning the origin of the soft-shelled turtle, - Aspidonectes californiana Rivers. Proc. Calif. Acad. Sci. - 4th Ser., 7(2):33-35. - - - VAN DER SCHALIE, H. - - - 1945. The value of mussel distribution in tracing stream - confluence. Pap. Michigan Acad. Sci., Arts Letters, 1944, - 30:355-73, 4 figs., September. - - - VINYARD, W. C. - - - 1955. Epizoophytic algae from mollusks, turtles, and fish in - Oklahoma. Proc. Oklahoma Acad. Sci., 1953, 34:63-65, - January. - - - VIOSCA, P., JR. - - - 1923. An ecological study of the cold-blooded vertebrates of - southeastern Louisiana. Copeia, 1923(115):35-44, February 1. - - 1944. Distribution of certain cold-blooded animals in Louisiana in - relationship to the geology and physiography of the state. - Proc. Louisiana Acad. Sci., 8:47-62, 3 figs., December. - - - WEBB, R. G. - - - 1956. Size at sexual maturity in the male softshell turtle, - _Trionyx ferox emoryi_. Copeia, 1956(2):121-22, 1 fig., May - 29. - - 1959. Description of a new softshell turtle from the southeastern - United States. Univ. Kansas Publ. Mus. Nat. Hist., - 11(9):517-25, 1 fig., 2 pls., August 14. - - 1960. Type and type locality of the Gulf Coast spiny softshell - turtle, Trionyx spinifer asper (Agassiz). Breviora, No. - 129:1-8, 2 pls., December 21. - - - WEBB, R. G., and LEGLER, J. M. - - - 1960. A new softshell turtle (genus Trionyx) from Coahuila, Mexico. - Univ. Kansas Sci. Bull., 40(2):21-30, 2 pls., April 20. - - - WEBSTER, E. B. - - - 1936. A preliminary list of the reptiles and amphibians of - Pottawatomie County, Oklahoma, near Shawnee. Proc. Oklahoma - Acad. Sci., 1935, 16:20-22. - - - WEED, A. C. - - - 1923. Notes on reptiles and batrachians of central Illinois. - Copeia, 1923(116):47-50, March 15. - - - WELTER, W. A., and CARR, K. - - - 1939. Amphibians and reptiles of northeastern Kentucky. Copeia, - 1939 (3):128-30, September 9. - - - WHEELER, G. C. - - - 1947. The amphibians and reptiles of North Dakota. Amer. Midl. - Nat., 38(1):162-90, July. - - - WIED-NEUWIED, M. A. P. - - - * 1838. Reise in das innere Nord-America in den Jahren 1832 bis - 1834. Reise von Bethlehem nach Pittsburgh über die - Alleghanys, vom 17. September bis zum 7. October. Coblenz, - pp. 121-42 (from Carr, 1952:527). - - 1865. Verziechniss der reptilien welche auf einer reise im - nordlichen America beobachtet wurden. Nova Acta Acad. - Leopold.--Carol., 32:viii + 146, 7 pls. - - - WILLIAMS, E. E. - - - 1950. Variation and selection in the cervical central articulations - of living turtles. Bull. Amer. Mus. Nat. Hist., - 94(9):509-61, 20 figs., 10 tables, March 24. - - - WILLIAMS, E. E., and MCDOWELL, S. B. - - - 1952. The plastron of soft-shelled turtles (Testudinata, - Trionychidae): a new interpretation. Jour. Morph., - 90(2):263-75, 2 pls., March. - - - WILLIAMS, K. L. - - - 1957. Yolk retraction as a possible cause of kyphosis in turtles. - Herpetologica, 13(Pt. 3):236, October 31. - - - WOOD, L. W. - - - 1959. New Ohio county records in the herpetology collection of the - Cleveland Museum of Natural History. Jour. Ohio Herp. Soc., - 2(2):8, September. - - - WRIGHT, A. H. - - - 1919. The turtles and the lizard of Monroe and Wayne counties, New - York. Copeia, 1919(66):6-8, February 25. - - - WRIGHT, A. H., and FUNKHOUSER, W. D. - - - 1915. A biological reconnaissance of the Okefinokee Swamp in - Georgia. The reptiles. Proc. Acad. Nat. Sci., Phila., - 67:107-92, 14 figs., 3 pls., April 23. - - - YARROW, H. C. - - - 1882. Check list of North American Reptilia and Batrachia, with - catalogue of specimens in the U. S. National Museum. Bull. - U. S. Nat. Mus., 24:vi + 249 pp. - - - ZANGERL, R. - - - 1939. The homology of the shell elements in turtles. Jour. Morph., - 65(3):383-407, 9 figs., 2 pls., November. - - -_Transmitted June 8, 1961._ - - - - - [Illustration: PLATE 31 - - _Trionyx ferox_, juveniles. _Top_--UMMZ 76755 (× 1) dorsal and - ventral views; Lake Griffin, Lake County, Florida. _Bottom_--TU - 13960 (× 3/4), dorsal and ventral views; Hillsborough River, - _ca._ 20 mi. NE Tampa, Hillsborough County, Florida.] - - [Illustration: PLATE 32 - - _Top_--_Trionyx ferox_, female, UMMZ 90010 (× 2/9); east edge - Okefinokee Swamp, Charlton County, Georgia. _Bottom_--Left, - _Trionyx ferox_, adult male, UMMZ 102276 (× 1/5), 14 mi. SE Punta - Gorda, Lee County, Florida; right, _Trionyx sinensis_, female, KU - 39417 (× 3/10), 5 mi. ESE Seoul, Korea. All dorsal views; note - resemblance of two species in having longitudinal ridging and - marginal ridge of carapace.] - - [Illustration: PLATE 33 - - _Trionyx spinifer spinifer_, juveniles, dorsal views. - _Top_--UMMZ 74518 (× 1-2/5); Portage Lake, Washtenaw County, - Michigan. - _Bottom_--TU 16132 (× 1-1/5); Sevierville, Sevier County, - Tennessee.] - - [Illustration: PLATE 34 - - _Trionyx spinifer spinifer_, dorsal views. - _Top_--Adult male, UMMZ 54401 (× 3/7), Portage Lake, - Livingston County, Michigan. - _Bottom_--Female, UMMZ 81699 (× 2/7), Ottawa County, Michigan.] - - [Illustration: PLATE 35 - - _Trionyx spinifer hartwegi_, dorsal views. - _Top_--Juveniles; left, KU 40210 (× 9/10), 12-1/2 mi. - S, 1-1/4 mi. W Meade, Meade County, Kansas; right, KU 16531 - (× 1), Smoky Hill River, 3 mi. SW Elkader, Logan County, Kansas. - _Bottom_--Adult Males; left, KU 18385 (× 2/5), Arrington, - Comanche County, Kansas; right, KU 3758 (× 3/10), - Little Salt Marsh, Stafford County, Kansas.] - - [Illustration: PLATE 36 - - _Trionyx spinifer hartwegi._ - _Top_--Juveniles; left, TU 13885, dorsal view (× 3/4), - Little Vian Creek, 1 mi. E Vian, Sequoyah County, Oklahoma; - right, KU 3732, ventral view (× 5/7), Independence, - Montgomery County, Kansas. - _Bottom_--Adult female, TTC 719, dorsal view (× 2/7), 10 mi. S, - 2 mi. W Gruver, Hansford County, Texas.] - - [Illustration: PLATE 37 - - _Trionyx spinifer asper_, juveniles, dorsal views. - _Top_--Left, male, KU 50839 (× 9/10), Flint River, 1-1/2 mi. S - Bainbridge, Decatur County, Georgia; right, female, TU 15661 - (× 9/10), Blackwater River, 4.3 mi. NW Baker, Okaloosa County, - Florida. - _Bottom_--Left, male, TU 13623 (× 7/9), Yellow River, 3.1 mi. W - Hammond, Tangipahoa Parish, Louisiana; right, female, TU 14362 - (× 4/5), Hobolochito Creek, 1 mi. N Picayune, Pearl River County, - Mississippi.] - - [Illustration: PLATE 38 - - _Trionyx spinifer asper_, dorsal views. - _Top_--Left, adult male, TU 15869 (× 1/2), Escambia River, 1.2 mi. E - Century, Escambia County, Florida; right, female, TU 14673.3 - (× 1/2), Black Warrior River, 17-1/2 mi. SSW Tuscaloosa, - Tuscaloosa County, Alabama. - _Bottom_--Left, adult male, TU 17117 (× 1/4), Pearl River, - Varnado, Washington Parish, Louisiana; right, female, TU 16584 - (× 1/5), locality same as TU 15869.] - - [Illustration: PLATE 39 - - _Trionyx spinifer pallidus_, new subspecies, dorsal views. - _Top_--Juveniles; left, TU 481 (× 2/3), Caddo Lake, Caddo Parish, - Louisiana; right, KU 50832 (× 9/10), mouth of Caney Creek, 4 mi. - SW Kingston, Marshall County, Oklahoma. - _Bottom_--Adult males; left, holotype, TU 484 (× 1/3), locality - same as TU 481; right, TU 1122 (× 2/9), Lacassine Refuge, - Cameron Parish, Louisiana.] - - [Illustration: PLATE 40 - - _Trionyx spinifer pallidus_, new subspecies, dorsal views. - _Top_--Females; left, TU 13213 (× 1/4), Sabine River, 8 mi. SW - Negreet, Sabine Parish, Louisiana; right, TU 13266 (× 2/9), - Sabine River, 8 mi. SW Merryville, Beauregard Parish, Louisiana. - _Bottom_--Left, adult male, SM 2889 (× 1/4), Groveton, Trinity - County, Texas; right, female, TU 14402 (× 1/5), Trinity River, - near junction with Big Creek, Liberty County, Texas.] - - [Illustration: PLATE 41 - - _Trionyx spinifer guadalupensis_, new subspecies, dorsal views. - _Top_--Juveniles; left, ANSP 16717 (× 1), no data; right, KU - 50834 (× 1-1/10), Hondo Creek, 4 mi. W Bandera, Bandera County, - Texas. - _Bottom_--Adult males; left, holotype UMMZ 89926 (× 1/3), 15 mi. - NE Tilden, McMullen County, Texas; right, SM 659 (× 3/10), - Colorado River, near Austin, Travis County, Texas.] - - [Illustration: PLATE 42 - - _Trionyx spinifer guadalupensis_, new subspecies, dorsal views. - _Top_--Adult females; left, TU 16036.1 (× 1/5), Llano River, - 2 mi. W Llano, Llano County, Texas; right, TU 10160 (× 1/5), - Guadalupe River, 9 mi. SE Kerrville, Kerr County, Texas. - _Bottom_--Left, female, CM 3118 (× 3/4), Black Bayou, Victoria - County, Texas; right, male, TU 14419.6 (× 5/9), San Saba River, - 11 mi. NNW San Saba, San Saba County, Texas.] - - [Illustration: PLATE 43 - - _Trionyx spinifer emoryi_, dorsal views. - _Top_--Juveniles; left, UMMZ 69411 (× 3/4), Río Conchos, 9 mi. - N Linares, Nuevo León, México; right, UMMZ 69412 (× 5/6), - Río Purificación, north Ciudad Victoria, Tamaulipas, México. - _Bottom_--Adult males; left, topotype, TU 11561 (× 1/3), - Brownsville, Cameron County, Texas; right, KU 48217 (× 1/3), - Black River Village, Eddy County, New Mexico.] - - [Illustration: PLATE 44 - - _Trionyx spinifer emoryi_, dorsal views. _Top_--Left, adult male, - KU 51194 (× 2/7), Río Conchos, near Meoquí, Chihuahua, México; - right, female, KU 3119 (× 4/9), Salt River, Phoenix, Maricopa - County, Arizona. - _Bottom_--Females; left, KU 3118 (× 1/5), locality same as KU 3119; - right, TU 14453 (× 3/10), Pecos River, near junction with - Independence Creek, Terrell County, Texas.] - - [Illustration: PLATE 45 - - _Trionyx muticus muticus_, juveniles, dorsal views. - _Top_--Topotypes (× 1), Wabash River, 2 mi. S New Harmony, Posey - County, Indiana; left, INHS 7278; right, INHS 7279. - _Bottom_--Left, TU 14375 (× 3/4), Trinity River near junction with - Big Creek, Liberty County, Texas; right, KU 50845 (× 1-2/5), - 4 mi. N Atwood, Hughes County, Oklahoma.] - - [Illustration: PLATE 46 - - _Trionyx muticus muticus_, dorsal views. - _Top_--Adult males; left, TU 14606 (× 3/10), White River, Cotter, - Marion County, Arkansas; right, KU 48237 (× 1/3), 8 mi. S - Hanover, Washington County, Kansas. - _Bottom_--Females (× 1/4), 2 mi. E Manhattan, in Pottawatomie - County, Kansas; left, KU 48229; right, KU 48238.] - - [Illustration: PLATE 47 - - _Trionyx muticus calvatus_, dorsal views. - _Top_--Juvenile, TU 17303 (× 1-2/5), Pearl River, Varnado, - Washington Parish, Louisiana. - _Bottom_--Left, adult male, KU 47118 (× 3/10), Pearl River within - 4 mi. of Monticello, Lawrence County, Mississippi; right, adult - female, TU 17306 (× 2/9), Pearl River, 9 mi. S Monticello, - Lawrence County, Mississippi.] - - [Illustration: PLATE 48 - - FIG. 1. Habitat of _T. s. pallidus_, Little River, 6.5 mi. S - Broken Bow, McCurtain County, Oklahoma, September 7, 1953. - - FIG. 2. Habitat of _T. s. emoryi_, Río Mesquites, 2 mi. W - Nadadores, Coahuila, México, July 27, 1959. Two _emoryi_ were - trapped in hoop nets set in quiet water to left of what is - believed to be a muskrat house.] - - [Illustration: PLATE 49 - - FIG. 1. General habitat of _T. s. pallidus_ and _T. m. muticus_, - Lake Texoma, in a period of low water, 2 mi. E Willis, Marshall - County, Oklahoma, February 24, 1951. - - FIG. 2. Type locality of _T. ater_, Tío Candido, 16 km. S Cuatro - Ciénegas, Coahuila, México, July 30, 1959. An adult male of - _T. s. emoryi_ was also netted here.] - - [Illustration: PLATE 50 - - FIG. 1. General habitat of _T. s. asper_ and _T. m. calvatus_, - Escambia River, 2 mi. E, 1/2 mi. N Century, Escambia County, - Florida, June 1, 1954. Three nests of _calvatus_ found on - sand bar in foreground.] - - FIG. 2. Nest site of _T. m. calvatus_ (excavated by investigator) - on open sand bar shown above in Fig. 1, June 1, 1954. Note - tracks of turtle in foreground leading toward and away - from disturbed area at left. - - [Illustration: PLATE 51 - - FIG. 1. Eggs of _T. m. calvatus in situ_, June 1, 1954, - approximately six inches below surface, from nest shown in - Fig. 2, Pl. 50. Note sandy substrate and seemingly irregular - arrangement of eggs. - - FIG. 2. Eggs of _T. m. calvatus in situ_, June 1, 1954; nest - located at brim of incline shown in foreground of Fig. 1, - Pl. 50. Note gravelly substrate (in foreground) and - symmetrical arrangement of eggs.] - - [Illustration: PLATE 52 - - Lectotype of _Trionyx spinifer_ Lesueur, Museum d'Histoire - Naturelle, Paris, No. 8808 (× 1/5); obtained by C. A. Lesueur - from the Wabash River, New Harmony, Posey County, Indiana. - _Top_--Dorsal view. _Bottom_--Ventral view.] - - [Illustration: PLATE 53 - - Lectotype of _Trionyx muticus_ Lesueur, Museum d'Histoire - Naturelle, Paris, No. 8813 (× 1/2); obtained by C. A. Lesueur - from the Wabash River, New Harmony, Posey County, Indiana. - _Top_--Dorsal view. - _Bottom_--Ventral view.] - - [Illustration: PLATE 54 - - Skull of holotype of _Platypeltis agassizi_ Baur (= _T. s. asper_), - MCZ 37172 (× 1), Savannah River, Georgia. - _Top_--Dorsal view. - _Bottom_--Ventral view.] - - -28-7818 - - - -UNIVERSITY OF KANSAS PUBLICATIONS - -MUSEUM OF NATURAL HISTORY - -Institutional libraries interested in publications exchange may obtain -this series by addressing the Exchange Librarian, University of Kansas -Library, Lawrence, Kansas. Copies for individuals, persons working in a -particular field of study, may be obtained by addressing instead the -Museum or Natural History, University of Kansas, Lawrence, Kansas. There -is no provision for sale of this series by the University Library, which -meets institutional requests, or by the Museum of Natural History, which -meets the requests of individuals. However, when individuals request -copies from the Museum, 25 cents should be included, for each separate -number that is 100 pages or more in length, for the purpose of defraying -the costs of wrapping and mailing. - -* An asterisk designates those numbers of which the Museum's supply (not -the Library's supply) is exhausted. Numbers published to date, in this -series, are as follows: - - Vol. 1. Nos. 1-26 and index. Pp. 1-638, 1946-1950. - - *Vol. 2. (Complete) Mammals of Washington. By Walter W. Dalquest. Pp. 1-444, 140 - figures in text. April 9, 1948. - - Vol. 3. *1. The avifauna of Micronesia, its origin, evolution, and - distribution. By Rollin H. Baker. Pp. 1-359, 16 figures - in text. June 12, 1951. - - *2. A quantitative study or the nocturnal migration of - birds. By George H. Lowery, Jr. Pp. 361-472, 47 figures - in text. June 29, 1951. - - 3. Phylogeny of the waxwings and allied birds. By M. Dale - Arvey. Pp. 473-530, 49 figures in text, 13 tables. - October 10, 1951. - - 4. Birds from the state of Veracruz, Mexico. By George H. - Lowery, Jr., and Walter W. Dalquest. Pp. 531-649, 7 - figures in text, 2 tables. October 10, 1951. - - Index. Pp. 651-681. - - *Vol. 4. (Complete) American weasels. By E. Raymond Hall. Pp. 1-466, - 41 plates, 31 figures in text. December 27, 1951. - - Vol. 5. Nos. 1-37 and index. Pp. 1-676, 1951-1953. - - *Vol. 6. (Complete) Mammals of Utah, _taxonomy and distribution_. - By Stephen D. Durrant. Pp. 1-549, 91 figures in text, - 30 tables. August 10, 1952. - - Vol. 7. *1. Mammals of Kansas. By E. Lendell Cockrum. Pp. 1-303, - 73 figures in text, 37 tables. August 25, 1952. - - 2. Ecology of the opossum on a natural area in northeastern - Kansas. By Henry S. Fitch and Lewis L. Sandidge. Pp. - 305-338, 5 figures in text. August 24, 1953. - - 3. The silky pocket mice (Perognathus flavus) of Mexico. By - Rollin H. Baker. Pp. 339-347, 1 figure in text. - February 15, 1954. - - 4. North American jumping mice (Genus Zapus). By Phillip H. - Krutzsch. Pp. 349-472, 47 figures in text, 4 tables. - April 21, 1954. - - 5. Mammals from Southeastern Alaska. By Rollin H. Baker and - James S. Findley. Pp. 473-477. April 21, 1954. - - 6. Distribution of Some Nebraskan Mammals. By J. Knox - Jones, Jr. Pp. 479-487. April 21, 1954. - - 7. Subspeciation in the montane meadow mouse, Microtus - montanus, in Wyoming and Colorado. By Sydney Anderson. - Pp. 489-506, 2 figures in text. July 23, 1954. - - 8. A new subspecies of bat (Myotis velifer) from - southeastern California and Arizona. By Terry A. - Vaughan. Pp. 507-512. July 23, 1954. - - 9. Mammals of the San Gabriel mountains of California. By - Terry A. Vaughan. Pp. 513-582, 1 figure in text, 12 - tables. November 15, 1954. - - 10. A new bat (Genus Pipistrellus) from northeastern - Mexico. By Rollin H. Baker. Pp. 583-586. November 15, - 1954. - - 11. A new subspecies of pocket mouse from Kansas. By E. - Raymond Hall. Pp. 587-590. November 15, 1954. - - 12. Geographic variation in the pocket gopher, Cratogeomys - castanops, in Coahuila, Mexico. By Robert J. Russell - and Rollin H. Baker. Pp. 591-608. March 15, 1955. - - 13. A new cottontail (Sylvilagus floridanus) from - northeastern Mexico. By Rollin H. Baker. Pp. 609-612. - April 8, 1955. - - 14. Taxonomy and distribution of some American shrews. By - James S. Findley. Pp. 613-618. June 10, 1955. - - 15. The pigmy woodrat, Neotoma goldmani, its distribution - and systematic position. By Dennis G. Rainey and Rollin - H. Baker. Pp. 619-624, 2 figures in text. June 10, - 1955. - - Index. Pp. 625-651. - - Vol. 8. Nos. 1-10 and index. Pp. 1-675, 1954-1956. - - Vol. 9. 1. Speciation of the wandering shrew. By James S. Findley. - Pp. 1-68, 18 figures in text. December 10, 1955. - - 2. Additional records and extension of ranges of mammals - from Utah. By Stephen D. Durrant, M. Raymond Lee, and - Richard M. Hansen. Pp. 69-80. December 10, 1955. - - 3. A new long-eared myotis (Myotis evotis) from - northeastern Mexico. By Rollin H. Baker and Howard J. - Stains. Pp. 81-84: December 10, 1955. - - 4. Subspeciation in the meadow mouse, Microtus - pennsylvanicus, in Wyoming. By Sydney Anderson. Pp. - 85-104, 2 figures in text. May 10, 1956. - - 5. The condylarth genus Ellipsodon. By Robert W. Wilson. - Pp. 105-116, 6 figures in text. May 19, 1956. - - 6. Additional remains of the multituberculate genus - Eucosmodon. By Robert W. Wilson. Pp. 117-123, 10 - figures in text. May 19, 1956. - - 7. Mammals of Coahuila, Mexico. By Rollin H. Baker. Pp. - 125-335, 75 figures in text. June 15, 1956. - - 8. Comments on the taxonomic status of Apodemus peninsulae, - with description of a new subspecies from North China. - By J. Knox Jones, Jr. Pp. 337-346, 1 figure in text, 1 - table. August 15, 1956. - - 9. Extension of known ranges of Mexican bats. By Sydney - Anderson. Pp. 347-351. August 15, 1956. - - 10. A new bat (Genus Leptonycteris) from Coahuila. By - Howard J. Stains. Pp. 353-356. January 21, 1957. - - 11. A new species of pocket gopher (Genus Pappogeomys) from - Jalisco, Mexico. By Robert J. Russell. Pp. 357-361. - January 21, 1957. - - 12. Geographic variation in the pocket gopher, Thomomys - bottae, in Colorado. By Phillip M. Youngman. Pp. - 363-387, 7 figures in text. February 21, 1958. - - 13. New bog lemming (genus Synaptomys) from Nebraska. By J. - Knox Jones, Jr. Pp. 385-388. May 12, 1958. - - 14. Pleistocene bats from San Josecito Cave, Nuevo León, - México. By J. Knox Jones, Jr. Pp. 389-396. December 19, - 1958. - - 15. New subspecies of the rodent Baiomys from Central - America. By Robert L. Packard. Pp. 397-404. December - 19, 1958. - - 16. Mammals of the Grand Mesa, Colorado. By Sydney - Anderson. Pp. 405-414, 1 figure in text, May 20, 1959. - - 17. Distribution, variation, and relationships of the - montane vole, Microtus montanus. By Sydney Anderson. - Pp. 415-511, 12 figures in text, 2 tables. August 1, - 1959. - - 18. Conspecificity of two pocket mice, Perognathus goldmani - and P. artus. By E. Raymond Hall and Marilyn Bailey - Ogilvie. Pp. 513-518, 1 map. January 14, 1960. - - 19. Records of harvest mice, Reithrodontomys, from Central - America, with description of a new subspecies from - Nicaragua. By Sydney Anderson and J. Knox Jones, Jr. - Pp. 519-529. January 14, 1960. - - 20. Small carnivores from San Josecito Cave (Pleistocene), - Nuevo León, México. By E. Raymond Hall. Pp. 531-538, 1 - figure in text. January 14, 1960. - - 21. Pleistocene pocket gophers from San Josecito Cave, - Nuevo León, México. By Robert J. Russell. Pp. 539-548, - 1 figure in text. January 14, 1960. - - 22. Review of the insectivores of Korea. By J. Knox Jones, - Jr., and David H. Johnson. Pp. 549-578. February 23, - 1960. - - 23. Speciation and evolution of the pygmy mice, genus - Baiomys. By Robert L. Packard. Pp. 579-670, 4 plates, - 12 figures in text. June 16, 1960. - - Index. Pp. 671-690. - - Vol. 10. 1. Studies of birds killed in nocturnal migration. By - Harrison B. Tordoff and Robert M. Mengel. Pp. 1-44, - 6 figures in text, 2 tables. September 12, 1956. - - 2. Comparative breeding behavior of Ammospiza caudacuta - and A. maritima. By Glen E. Woolfenden. Pp. 45-75, - 6 plates, 1 figure. December 20, 1956. - - 3. The forest habitat of the University of Kansas Natural - History Reservation. By Henry S. Fitch and Ronald R. - McGregor. Pp. 77-127, 2 plates, 7 figures in text, - 4 tables. December 31, 1956. - - 4. Aspects of reproduction and development in the prairie - vole (Microtus ochrogaster). By Henry S. Fitch. Pp. - 129-161, 8 figures in text, 4 tables. December 19, - 1957. - - 5. Birds found on the Arctic slope of northern Alaska. - By James W. Bee. Pp. 163-211, plates 9-10, 1 figure - in text. March 12, 1958. - - 6. The wood rats of Colorado: distribution and ecology. By - Robert B. Finley, Jr. Pp. 213-552, 34 plates, 8 figures - in text, 35 tables. November 7, 1958. - - 7. Home ranges and movements of the eastern cottontail - in Kansas. By Donald W. Janes. Pp. 553-572, 4 plates, - 3 figures in text. May 4, 1959. - - 8. Natural history of the salamander, Aneides hardyi. By - Richard F. Johnston and Gerhard A. Schad. Pp. 573-585. - October 8, 1959. - - 9. A new subspecies of lizard, Cnemidophorus sacki, from - Michoacán, México. By William E. Duellman. Pp. 587-598, - 2 figures in text. May 2, 1960. - - 10. A taxonomic study of the Middle American Snake, - Pituophis deppei. By William E. Duellman. Pp. 599-610, - 1 plate, 1 figure in text. May 2, 1960. - - Index. Pp. 611-626. - - Vol. 11. 1. The systematic status of the colubrid snake, - Leptodeira discolor Günther. By William E. Duellman. - Pp. 1-9, 4 figures. July 14, 1958. - - 2. Natural history of the six-lined racerunner, - Cnemidophorus sexlineatus. By Henry S. Fitch. - Pp. 11-62, 9 figures, 9 tables. September 19, 1958. - - 3. Home ranges, territories, and seasonal movements of - vertebrates of the Natural History Reservation. By - Henry S. Fitch. Pp. 63-326, 6 plates, 24 figures in - text, 3 tables. December 12, 1958. - - 4. A new snake of the genus Geophis from Chihuahua, - Mexico. By John M. Legler. Pp. 327-334, 2 figures - in text. January 28, 1959. - - 5. A new tortoise, genus Gopherus, from north-central - Mexico. By John M. Legler. Pp. 335-343. April 24, 1959. - - 6. Fishes of Chautauqua, Cowley and Elk counties, Kansas. - By Artie L. Metcalf. Pp. 345-400, 2 plates, 2 figures - in text, 10 tables. May 6, 1959. - - 7. Fishes of the Big Blue river basin, Kansas. By W. L. - Minckley. Pp. 401-442, 2 plates, 4 figures in text, - 5 tables. May 8, 1959. - - 8. Birds from Coahuila, México. By Emil K. Urban. - Pp. 443-516. August 1, 1959. - - 9. Description of a new softshell turtle from the - southeastern United States. By Robert G. Webb. - Pp. 517-525, 2 plates, 1 figure in text. - August 14, 1959. - - 10. Natural history of the ornate box turtle, Terrapene - ornata ornata Agassiz. By John M. Legler. Pp. 527-669, - 16 pls., 29 figures in text. March 7, 1960. - - Index Pp. 671-703. - - Vol. 12. 1. Functional morphology of three bats: Eumops, Myotis, - Macrotus. By Terry A. Vaughan. Pp. 1-153, 4 plates, - 24 figures in text. July 8, 1959. - - 2. The ancestry of modern Amphibia: a review of the - evidence. By Theodore H. Eaton, Jr. Pp. 155-180, - 10 figures in text. July 10, 1959. - - 3. The baculum in microtine rodents. By Sydney Anderson. - Pp. 181-216, 49 figures in text. February 19, 1960. - - 4. A new order of fishlike Amphibia from the Pennsylvanian - of Kansas. By Theodore H. Eaton, Jr., and Peggy Lou - Stewart. Pp. 217-240, 12 figures in text. May 2, 1960. - - More numbers will appear in volume 12. - - Vol. 13. 1. Five natural hybrid combinations in minnows (Cyprinidae). - By Frank B. Cross and W. L. Minckley. Pp. 1-18. - June 1, 1960. - - 2. A distributional study of the amphibians of the Isthmus - of Tehuantepec, México. By William E. Duellman. Pp. - 19-72, pls. 1-8, 3 figures in text. August 16, 1960. - - 3. A new subspecies of the slider turtle (Pseudemys - scripta) from Coahuila, México. By John M. Legler. Pp. - 73-84, pls. 9-12, 3 figures in text. August 16, 1960. - - 4. Autecology of the copperhead. By Henry S. Fitch. Pp. - 85-288, pls. 13-20, 26 figures in text. November 30, - 1960. - - 5. Occurrence of the garter snake, Thamnophis sirtalis, in - the great plains and Rocky mountains. By Henry S. Fitch - and T. Paul Maslin. Pp. 289-308, 4 figures in text. - February 10, 1961. - - 6. Fishes of the Wakarusa river in Kansas. By James E. - Deacon and Artie L. Metcalf. Pp. 309-322, 1 figure in - text. February 10, 1961. - - 7. Geographic variation in the North American Cyprinid - fish, Hybopsis gracilis. By Leonard J. Olund and Frank - B. Cross. Pp. 323-348, pls. 21-24, 2 figures in text. - February 10, 1961. - - 8. Descriptions of two species of frogs, genus Ptychohyla; - studies of American Hylid frogs, V. By William E. - Duellman. Pp. 349-357, pl. 25, 2 figures in text. April - 27, 1961. - - 9. Fish populations, following a drought, in the Neosho and - Marais des Cygnes rivers of Kansas. By James Everett - Deacon. Pp. 359-427, pls. 26-30, 3 figures in text. - August 11, 1961. - - 10. North American recent soft-shelled turtles (family - Trionychidae). By Robert G. Webb. Pp. 429-611, pls. - 31-54, 24 figures in text. February 16, 1962. - - Vol. 14. 1. Neotropical bats from western México. By Sydney Anderson. - Pp. 1-8. October 24, 1960. - - 2. Geographic variation in the harvest mouse, - Reithrodontomys megalotis, on the central great plains - and in adjacent regions. By J. Knox Jones, Jr., and B. - Mursaloglu. Pp. 9-27, 1 figure in text. July 24, 1961. - - 3. Mammals of Mesa Verde national park, Colorado. By Sydney - Anderson. Pp. 29-67, pls. 1 and 2, 3 figures in text. - July 24, 1961. - - 4. A new subspecies of the black myotis (bat) from eastern - México. By E. Raymond Hall and Ticul Alvarez. Pp. - 69-72, 1 fig. in text. December 29, 1961. - - 5. North American yellow bats, "Dasypterus," and a list - of the named kinds of the genus Lasiurus Gray. By E. - Raymond Hall and J. Knox Jones, Jr. Pp. 73-98, 4 figs. - in text. December 29, 1961. - - 6. Natural history of the brush mouse (Peromyscus boylii) - in Kansas with description of a new subspecies. By - Charles A. Long. Pp. 99-110, 1 fig. in text. December - 29, 1961. - - 7. Taxonomic status of some mice of the Peromyscus boylii - group in eastern México, with description of a new - subspecies. By Ticul Alvarez. Pp. 111-120, 1 fig. in - text. December 29, 1961. - - More numbers will appear in volume 14. - - Vol. 15. 1. The amphibians and reptiles of Michoacán, México. - By William E. Duellman. Pp. 1-148, pls. 1-6, - 11 figures in text. December 20, 1961. - - 2. Some reptiles and amphibians from Korea. By Robert G. - Webb, J. Knox Jones, Jr., and George W. Byers. Pp. - 149-173. January 31, 1962. - - More numbers will appear in volume 15. - - - - -Transcriber's Notes - -All obvious typographical error were corrected. Due to variant usage -of hyphens, "soft-shelled" and "crystal-clear" were used as the -standard for variants of those terms. All other variant spellings -of "softshell(s)" and where variant spellings occur in quoted text -or literature titles they were retained. Variants in accented -and non-accented words may exist. Paragraphs split by tables or -illustrations were rejoined. - - -Typographical Corrections - - Page Correction - ==== ===================== - 494 Ordinance School Proving Ground => Ordnance - 494 Pl. 12, top => Pl. 42, top - 567 Pl. 52, Fig. 2 => Pl. 51, Fig. 2 - 576 _Agkistrodon piscivorous_ => _piscivorus_ - 595 Carettochlydae => Carettochelyidae - - - - - - - -End of the Project Gutenberg EBook of North American Recent Soft-shelled -Turtles (Family Trionychidae), by Robert G. 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