UNIVERSITY OF KANSAS PUBLICATIONS MUSEUM OF NATURAL HISTORY Volume 13, No. 3, pp. 73-84, pls. 9-12, 3 figs. August 16, 1960 A New Subspecies of Slider Turtle (Pseudemys scripta) from Coahuila, México BY JOHN M. LEGLER UNIVERSITY OF KANSAS LAWRENCE 1960 UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY Editors: E. Raymond Hall, Chairman, Henry S. Fitch, Robert W. Wilson Volume 13, No. 3, pp. 73-84, pls. 9-12, 3 figs. Published August 16, 1960 UNIVERSITY OF KANSAS Lawrence, Kansas PRINTED IN THE STATE PRINTING PLANT TOPEKA, KANSAS 1960 28-3860 A New Subspecies of Slider Turtle (Pseudemys scripta) from Coahuila, México BY JOHN M. LEGLER In September, 1958, the author and two colleagues collected a large series of _Pseudemys_ in small ponds and in a river in the basin of Cuatro Ciénegas, Coahuila. The specimens prove to represent a previously unrecognized subspecies of _Pseudemys scripta_. The subspecies is named in honor of Edward Harrison Taylor who has contributed more than any other person to our present knowledge of the herpetofauna of México. =Pseudemys scripta taylori= new subspecies (Pls. 9-12, Figures 1 & 2) _Holotype._--Univ. Kansas Mus. Nat. Hist., No. 46952, adult female, alcoholic; 16 km. S Cuatro Ciénegas, Coahuila, México; 6 September 1958; original number 1694 John M. Legler. _Paratypes._--A total of 52 specimens as follows (numbers or series of numbers marked with an asterisk are for specimens prepared as dry shell with soft parts in alcohol): KU 46932-4*, 46949-51, 46953-67, 46969 (females), 46935*, 46936-48, 46968 (males), same data as holotype, 6 to 8 September 1958; UU 3416 (male), same locality, 29 to 30 July 1959; KU 46971, 46973* (females), 46972 (male), 46970, 46974 (juveniles), 6 mi. W Cuatro Ciénegas, 3 to 6 September 1958; IU 43585, 43587-9 (females), 43586, 43590 (males), same locality, 11 July 1958; CNHM 55655 (female), same locality, 22 August 1939; KU 46976 (female), Río Chiquito, 10 km. S Cuatro Ciénegas, 9 September 1958; UU 3415 (female), 8.5 mi. SW Cuatro Ciénegas, 1 August 1959. _Diagnosis._--A subspecies of _Pseudemys scripta_ most closely resembling _P. s. elegans_, but differing from that subspecies in having: 1) extensive _black_ plastral pattern, all parts of which are interconnected, covering approximately half of plastron; 2) tendency toward melanism, in large adults of both sexes, especially noticeable on posterior part of plastron; 3) cutting edge of lower jaw coarsely serrate; 4) tendency for femoral edges of plastron to be reflected ventrally, especially in males; and, 5) pectoral scute longer than gular. _Description of holotype_ (measurements given in Table 1).--Carapace oval in dorsal aspect, slightly narrowed behind, nearly straight across anterior margin, bluntly serrate behind; shell deep, highly arched in cross section; height of shell 53 per cent of width; surface of shell having longitudinal striations; middorsal keel weakly developed, scarcely discernible except on third central lamina; lateral margin of carapace not at all reflected, posterolateral margins flared outward; central laminae all broader than long, the first urn-shaped. TABLE 1. MEASUREMENTS (IN MILLIMETERS) OF THE HOLOTYPE (46952) AND NINE ADULT, TOPOTYPIC PARATYPES OF PSEUDEMYS SCRIPTA TAYLORI NEW SUBSPECIES. HEIGHT WAS MEASURED IN A VERTICAL LINE FROM THE CENTER OF THE PLASTRON. KEY: A: Collection and Catalogue No. B: Sex C: Length of Carapace D: Width of Carapace E: Length of Plastron F: Width of Plastral Forelobe (Humeropectoral) G: Width of Plastral Hind Lobe (Mid-femoral) H: Height I: Width of Head ================================================================= A | B | C | D | E | F | G | H | I -----------+----------+-----+-----+-----+-----+-----+-----+------ KU 46948 | [Male] | 179 | 127 | 157 | 71 | 69 | 69 | 28 KU 46941 | [Male] | 148 | 107 | 129 | 59 | 59 | 57 | 25 KU 46968 | [Male] | 139 | 99 | 116 | 55 | 54 | 57 | 25 KU 46937 | [Male] | 128 | 100 | 115 | 54 | 52 | 47 | 21 KU 46944 | [Male] | 105 | 82 | 93 | 46 | 43 | 38 | 19 KU 46932 | [Female] | 214 | 158 | 196 | 86 | 84 | 87 | 37 KU 46952 | [Female] | 202 | 149 | 186 | 87 | 86 | 79 | 33 KU 46957 | [Female] | 188 | 138 | 167 | 79 | 80 | 68 | 31 KU 46959 | [Female] | 156 | 118 | 149 | 71 | 71 | 70 | 29 KU 46962 | [Female] | 132 | 101 | 119 | 58 | 53 | 51 | 24 -----------+----------+-----+-----+-----+-----+-----+-----+------ Ground color of carapace (hereinafter, colors are those of preserved specimen) dark olive; upper surface of each marginal scute having round or oval black mark, two such marks on each marginal of first pair; marks on margin of anterior half of carapace having pale orange-yellow borders, marks more posteriorly having indistinct borders or no border; upper surface of carapace having numerous, irregularly arranged black marks on a faint reticulum of pale lines; one or two large oval marks on each lateral scute arranged more or less vertically, other marks on laterals irregular in size and arrangement; central scutes having three to five longitudinally arranged, narrow black marks on each scute. Ground color of plastron pale yellow, anterior half extensively marked with black along laminal seams; all plastral markings interconnected; undersurfaces of marginals on anterior half of shell having pale centers; undersurfaces of posterior marginals and posterior half of plastron solid black. Plastron more or less evenly rounded in front, slightly indented on gular border; posterolateral free edge of plastron reflected slightly downward; posterior border of plastron having wide shallow anal notch; plastral laminae, in order of length--abdominal, anal, pectoral, gular, femoral, humeral; abdominal lamina longer than combined lengths of pectoral and humeral or humeral and gular. Head moderately wide; snout slightly pointed in dorsal view, curving evenly backward and downward from nostrils in profile; upper jaw notched in middle, cutting edges finely and unevenly serrate, crushing surfaces having distinct ridge bearing fine denticulations but no large teeth; cutting edges of lower jaw coarsely and evenly serrate, tooth at symphysis relatively large; raised ridges of lower crushing surfaces each having low blunt tooth and many fine denticulations. Major markings of head and neck as follows: narrow stripe beginning at posterior edge of eye and extending downward and backward (across tympanum) on side of neck to shoulder (stripe wider behind than at origin); wide stripe from lower posterior corner of eye extending downward, across mandibular articulation (and below tympanum) on throat to shoulder (wider at origin than behind); postorbital mark, four to five millimeters wide, approximately 26 millimeters long, connected to eye by narrow isthmus anteriorly and continuous with narrow stripe on upper part of neck posteriorly; stripe on mandibular symphysis widened and bifurcated posteriorly, its two branches enclosing one wide and two narrow stripes; wide stripe beginning in middle of mandibular ramus and running backward to point below mandibular articulation on each side; top of head, sides of snout, and areas between above-mentioned major stripes, marked with numerous, fine, often indistinct pale lines. Pale dorsal stripe on fleshy portion of each finger, those of second and fourth fingers continuous to mid-humeral region, those of other fingers broken on anterior face of antebrachium; upper and lower pale stripes of antebrachium joined in mid-humeral region. _Coloration of living specimens._--Ground color of soft parts dark olive to slate gray or black; ground color of carapace olive to slate gray; ground color of plastron pale yellow, markings blackish, tinged with brown in younger specimens, sooty black in most adults. Postorbital mark red; other markings on soft parts cream to buffy yellow. _Geographic range._--_Pseudemys scripta taylori_ is known only from ponds, and the Río Chiquito in the basin of Cuatro Ciénegas. The discovery of _taylori_ brings to six the number of valid subspecies of _scripta_ known in México (_elegans_, _gaigeae_, _hiltoni_, _nebulosa_, _ornata_, and _taylori_) and to three (_elegans_, _gaigeae_, and _taylori_) the number known in Coahuila. My own studies of these six subspecies indicate that they are, beyond reasonable doubt, members of a single polytypic species (_scripta_). I tentatively follow Williams (1956:153) in rejecting "_cataspila_" as an invalid name. Three specimens of _Pseudemys scripta_ obtained by Robert G. Webb in the Río Chiquito at a point 8 mi. W of Nadadores, 2100 ft., where the river flows out of the basin of Cuatro Ciénegas, have many characteristics in common with _taylori_, but resemble _elegans_ closely in several characters as follows: no extensive melanism; plastral markings tending to be brownish; anterior plastral markings smudgelike, isolated or nearly isolated; markings on lateral scutes tending to have vertical, linear arrangement; cutting edge of mandible weakly serrate; femoral edges of plastron not reflected ventrally; one or more fine, pale lines between two major stripes on antebrachium; gular longer than pectoral in one specimen, longer than femoral in both specimens. The nature of these specimens suggests that parts of the Río Salado drainage north and east of Cuatro Ciénegas are in a zone of intergradation between _taylori_ and _elegans_. I have examined what I consider to be typical examples of _P. s._ _elegans_ from the region of Múzquiz (CNHM 28843-45, 55625-45), and from Don Martín Reservoir (KU 33524). These localities are, respectively, approximately 70 miles north-northeast and 100 miles east-northeast of Cuatro Ciénegas. The specimens from Múzquiz are presumably the same that Carr (1952:262) treated as "... _elegans-cataspila_ intergrades, but with a strong leaning toward eastern _elegans_...." Populations of _P. scripta_ in central eastern Coahuila (between the above-mentioned localities and Cuatro Ciénegas) probably are a conglomerate of only two subspecies (_elegans_ and _taylori_), not including _gaigeae_ (as was suggested by Hamilton, 1947:65 and by Carr, op. cit.:241, map 17;262). Specimens reported by Schmidt and Owens (1944:101) as _P. s. gaigeae_ (from several localities in the region mentioned above) have been examined in the course of my study and prove to be _P. floridana texana_. A specimen reported by Shannon and Smith (1949:399; IU 4094, Hidalgo Co., Texas) as being either _gaigeae_ or an _elegans-gaigeae_ intergrade, has been examined and is here regarded as a typical specimen of _elegans_. I regard _P. s. gaigeae_ as a subspecies of the upper Río Grande and disrupted parts of that drainage; the range of that subspecies meets that of _P. s. elegans_ somewhere between the Big Bend region and Piedras Negras. In any event, the influence of _gaigeae_ is not so widespread as other authors (Carr, _loc. cit._; Hamilton, _loc. cit._; Hartweg, 1939:3-4) have indicated. Further collecting in the Río Salado and its tributaries east and north of Cuatro Ciénegas will be necessary before the exact range of _P. s. taylori_ can be determined. _Variation._--Characteristics ascribed to the holotype pertain in general to all specimens in the hypodigm, except as noted below. The postorbital mark is in contact with the eye on one or both sides in 46 per cent of the specimens (narrowly separated from eye in remainder) and is in contact with a neck stripe (on one or both sides) in 35 per cent of the specimens. The pattern of the antebrachium is as shown in Fig. 2 in all specimens except that the thin lateral stripe is obliterated by melanism in older specimens of both sexes. The lateral edges of the posterior plastral lobe are reflected downward, at least slightly, in all but one specimen (an adult, kyphotic female). The first central lamina is straight-sided in juveniles and becomes urn-shaped only in adults. The relative height of the shell tends to increase with a general increase in size in both sexes. [Illustration: FIG. 1. _Pseudemys scripta taylori_ new subspecies: left side of head, female paratype (KU 46933), × 1.] [Illustration: FIG. 2. _Pseudemys scripta taylori_ new subspecies: anterior view of left antebrachium, female paratype (KU 46934), × 1.] _Comparisons._--Of the five other subspecies of Mexican _P. scripta_ mentioned above, three subspecies (_gaigeae_, _hiltoni_, and _nebulosa_) form a natural group herein referred to as the _gaigeae_ group. _Pseudemys s. taylori_ is distinguished from members of the _gaigeae_ group by elongate, red postorbital mark (yellow or orange in the _gaigeae_ group), extensive black plastral pattern (narrow--or if wide, brownish--in _gaigeae_ group), and serrate lower jaw (nearly smooth in _gaigeae_ group). The subspecies _P. scripta taylori_ differs from _P. scripta elegans_ as indicated in the following comparative list of characteristics: _P. s. taylori_ _P. s. elegans_ 1. Extensive black plastral 1. Plastral pattern consisting pattern, all parts of which of separate brown smudges (at are interconnected. Plastral least anteriorly). Plastral pattern partly obliterated by pattern obliterated by melanism in old individuals melanism only in adult males. of both sexes. 2. Markings of carapace in form 2. Markings of carapace having of indistinct ocelli. linear and vertical. 3. Cutting edge of mandible 3. Cutting edge of mandible serrate. smooth. 4. Foreclaws of mature males 4. Foreclaws of mature males unmodified. greatly elongated. 5. Gular shorter than pectoral 5. Gular longer than pectoral (91 per cent of specimens), (90 per cent of specimens) gular and femoral subequal. and longer than femoral (all specimens). 6. Shell relatively higher, 6. Shell relatively lower, posterior lobe of plastron posterior lobe of plastron relatively narrower (Fig. 3). relatively wider (Fig. 3). 7. Lateral edges of posterior 7. Lateral edges of posterior plastral lobe reflected plastral lobe unmodified. downward. Four specimens of _P. s. ornata_ (MCZ 46392-3, 46397, 46400, two adult females and two adult males) from the Río Soto la Marina drainage of Tamaulipas differ from _P. s. taylori_ as follows: plastral pattern diffuse and brownish, not black; gular longer than pectoral; cutting edge of lower jaw only slightly serrate; stripe on mandibular symphysis isolated, not joined with ventral neck stripes to form inverted Y; postorbital stripe (yellow in preservative) connected to eye by narrow isthmus and continuous with neck stripe to shoulder. In _P. s. taylori_ there is an obtuse ridge or prominence across the bridge, on a line joining the free lateral edges of the plastron; the area between the ridges is nearly flat. The bridge forms a distinct plane on each side between the mentioned ridge and the outer edges of the marginals. In cross section this plane forms an angle of 30 to 45 degrees with the horizontal plane of the plastron. The higher bridge and deeper shell of _taylori_ result in a slightly higher center of gravity in this subspecies than in the specimens of _elegans_ and _ornata_ I have examined. In the two subspecies last named the longitudinal ridges on the plastron are indistinct or wanting and the bridge forms a lesser angle with the horizontal plane of the plastron. The largest female of _taylori_ (218 mm.) is shorter by some 30 mm. than the smaller female in the series of _ornata_ from Tamaulipas whereas the largest male of _taylori_ (179 mm.) is shorter by some 80 mm. than the smaller male from Tamaulipas. _Pseudemys s. taylori_ probably is smaller, on the average, than either _elegans_ or northern populations of _ornata_. There seems to be no reliable published record of the color of the postorbital mark in living examples of _P. s. ornata_ from Tamaulipas. Williams (1956:147, 154) indicated that this color may be red or yellow for Mexican and Central American populations of _ornata_ in general and Günther (1885: Pl. 6 b) indicated that the color was yellow in _Emys cataspila_; however, both of the observations mentioned were presumably based on preserved rather than living specimens. The postorbital marks of a live specimen of _ornata_ (KU 40131) from southern Veracruz were yellowish to buffy with a pinkish tinge anteriorly (_fide_ notes of Robert G. Webb and a color photograph by him). [Illustration: FIG. 3. Relative height of shell (expressed as a percentage of width) and relative width of posterior plastral lobe (expressed as a percentage of plastral length) in two subspecies of _Pseudemys scripta_. The data presented are for 62 specimens (40 [Female], 22 [Male]) of _P. s. taylori_ and 37 specimens (13 [Female], 24 [Male]) of _P. s. elegans_. Horizontal and vertical lines represent the mean and range, respectively, whereas open and solid rectangles represent one standard deviation and two standard errors of the mean, respectively.] [Illustration: PLATE 9 _Pseudemys scripta taylori_ new subspecies: dorsal view of holotype (KU 46952), approximately 11/16 natural size.] [Illustration: PLATE 10 _Pseudemys scripta taylori_ new subspecies: ventral view of holotype (KU 46952), approximately 11/16 natural size.] [Illustration: PLATE 11 Paratypes of _Pseudemys scripta taylori_ new subspecies: _Left_--dorsal and ventral views of KU 46943, male, 16 km. S Cuatro Ciénegas, × 3/8; _Upper right_--KU 46974, juvenile, 6 mi. W Cuatro Ciénegas, × 5/6; _Lower right_--KU 46968, male, 16 km. S Cuatro Ciénegas, × 3/8.] [Illustration: PLATE 12 Ventral views of four subspecies of _Pseudemys scripta_: _Upper left_--_P. s. ornata_ (KU 40131 [Female]), Río Playa Vicente, San Andrés Tuxtla, Veracruz, × 1/3; _Upper right_--_P. s. gaigeae_ (IU 43583 [Female]), 1 mi. E La Cruz, Chihuahua, × 3/8; _Lower left_--_P. s. elegans_ (CNHM 55627 [Male]), Múzquiz, Coahuila, × 2/3; _Lower right_--_P. s. taylori_ new subspecies (KU 46970 juvenile), paratype, 6 mi. W Cuatro Ciénegas, Coahuila, × 11/16.] _Natural history._--Specimens of _P. s. taylori_ were caught in hoop nets in clear deep pools and in the Río Chiquito. No specimens were collected or observed in marshy situations where the water was shallow or stagnant. Individuals were seen only near dusk and in early morning when a number floated just below the surface with only their heads showing. They were never seen on land during our short stay in the basin. The few stomachs that were opened contained vegetable material. In terms of number of specimens trapped, _P. s. taylori_ was the most abundant turtle in pools at and near the type locality (Webb and Legler, 1960). _Relationships and phylogeny._--The basin of Cuatro Ciénegas now drains, via the Río Salado, into the lower Río Grande. Brief descriptions of habitats and topography in the basin are given by Gilmore (1947:148-150, fig. 2) and Webb and Legler (1960). In the more northern parts of the Salado drainage (for example, in the Río Sabinas near Múzquiz) slider turtles are typical _P. s. elegans_. Assuming that conditions which permit genetic exchange between populations of turtles in the Salado drainage system differ in no major respect from conditions in other parts of the range of _Pseudemys scripta_, it is logical to suppose that the differentiation of _P. s. taylori_ at Cuatro Ciénegas was preceded by the isolation of a population in that basin. The Río Chiquito drains through a narrow gap in the northeastern end of the basin of Cuatro Ciénegas. Interruption of this stream would effectively isolate aquatic habitats in the basin. It is here proposed that _P. s. taylori_ is a relict of an earlier, lower Río Grande stock, part of which became isolated in the basin of Cuatro Ciénegas in postpluvial times. The morphological similarity of _P. s. taylori_ and _P. s. elegans_ indicates that both were derived from this parent stock; similarity of both subspecies to populations of _P. s. ornata_ in Tamaulipas suggests that the latter subspecies may also be a derivative of the mentioned stock of the lower Río Grande. The proposed former isolation of the basin of Cuatro Ciénegas is supported by evidence found in studies of other turtles in the basin. Of the four kinds of turtles known to occur there (_Terrapene coahuila_, _P. s. taylori_, _Trionyx spinifer emoryi_, and _Trionyx ater_), all but _T. spinifer_ seem to be endemic. These three kinds comprise a graded series, in regard to their degree of differentiation from closest known relatives, as follows: 1) _Terrapene coahuila_ is morphologically the most generalized and primitive of living box turtles; the species is unique in its highly aquatic mode of life (see Legler, 1960:532-534, for brief discussion of relationships within genus Terrapene); 2) _Trionyx ater_ seems to represent a relict population of pre-_Trionyx spinifer_ stock; presumably, _spinifer_ has reinvaded the basin of Cuatro Ciénegas in relatively recent times and, as noted above, _spinifer_ and _ater_ now occur sympatrically (at least in a geographic sense) in the basin (Webb and Legler, _op. cit._); and, 3) evidence presented above suggests that _P. s. taylori_ intergrades with _P. s. elegans_ outside the basin. The three endemic populations of turtles at Cuatro Ciénegas therefore, differ by varying degrees from their closest living relatives. This variation in degree of difference possibly results from varying periods of isolation. Probably the basin of Cuatro Ciénegas has been isolated from, and reconnected to, the lower Río Grande drainage at several times in the past. The relationships of fishes in the basin, now under study by other workers, also suggest that the basin was isolated more than once. _Remarks._--Local names for the above-mentioned localities in the basin of Cuatro Ciénegas are as follows: Anteojo (6 mi. W Cuatro Ciénegas); El Mojarral (8.5 mi. SW); and Ojo de Agua de Tío Candido, on Rancho Orozco (16 km. S). The Río Chiquito is referred to by some natives as "Río Colorado" and by some as "Río Salado." The local name for _P. s. taylori_ is _tortuga negra_ (the name is used also for _Terrapene coahuila_). _Acknowledgments._--For permission to examine specimens in their care, I wish to thank Doris M. Cochran, Smithsonian Institution (USNM), Ernest E. Williams, Museum of Comparative Zoology (MCZ), Rollin H. Baker, Michigan State University (MSU), Hobart M. Smith, University of Illinois (IU), and Robert F. Inger, Chicago Natural History Museum (CNHM). Pete S. Chrapliwy, John K. Greer, Robert G. Webb, and Kenneth L. Williams all contributed field data concerning the specimens of _P. s. taylori_ that they collected. I am especially grateful to Webb for donating two specimens to the University of Utah (UU). Special gratitude is expressed to Wendell L. Minckley and Robert B. Wimmer for assistance with field work at Cuatro Ciénegas. Daniel Rodríguez, Cuatro Ciénegas, guided us to the various ponds at and near the type locality. Robert R. Miller, Robert G. Webb, and Donald Tinkle read the manuscript and offered helpful criticisms. Figures 1 and 2 were drawn by Lorna Cordonnier. _Comparative materials examined_ (total of 135 specimens).--_P. s. elegans_ (52 specimens): KU 2897-8, 3195, 18337, 18341, 18345, 18347, 18364, 45027-31, 45033, 46750, 46863, and John M. Legler 1394 and 1435, various localities, Kansas; KU 16400, Howard Co., Texas; KU 39983-4, 8 mi. N and 2 mi. W Piedras Negras, Coahuila; KU 33525, 33527-9, La Gacha, Coahuila; CNHM 28843-5, 55625-45, Rancho las Ruscias, Múzquiz, Coahuila; KU 39982, 2 mi. S and 3 mi. E San Juan de Sabinas, Coahuila; KU 33524, Don Martín Reservoir, Coahuila; _P. s. elegans_ × _taylori_ (3): KU 53785-7, 8 mi. W. Nadadores, Coahuila; _P. s. gaigeae_ (39): MCZ 54724, Elephant Butte Reservoir [Sierra or Socorro Co.], New Mexico; KU 51158-61, 51202-3, Lajitas, Brewster Co., Texas; KU 51162-6, 51204-6, 51315, 1 mi. NW Ojinaga, Chihuahua; KU 33884, 51167-72, 51207-20, 3 mi. N and 5 mi. E Meoqui, Chihuahua; IU 43583-4, La Cruz, Chihuahua; _P. s. ornata_ (9): MCZ 46392-3, Río Purificación, Rancho Sta. Ana, Tamaulipas; MCZ 46397, E of Güémez, Tamaulipas; MCZ 46400, Jiménez, Tamaulipas; KU 40161-2, Alvarado, Veracruz; KU 40131, San Andrés Tuxtla, Veracruz; V. E. Thatcher 98, 15 mi. N Teapa, Tabasco; KU 40139, Cantemo[c], Tabasco; _P. s. taylori_ (23 in addition to type series): KU 51438, 51442, 53788-53801 topotypes; KU 53802-5, 8.5 mi. SW Cuatro Ciénegas, Coahuila; KU 51439-41, 10 km. S Cuatro Ciénegas, Coahuila; _P. floridana texana_ (10 from Coahuila): KU 39985, 2 mi. W Jiménez; CNHM 55654, Allende; CNHM 55646, Cd. San Juan; CNHM 55648, Hermanas; CNHM 55649-53, Lampacitas; KU 33526, Don Martín Reservoir. LITERATURE CITED CARR, A. 1952. Handbook of turtles: the turtles of the United States, Canada, and Baja California. Cornell Univ. Press, xv+542 pp., 82 pls., 37 figs., 15 tables, 23 maps. GILMORE, R. M. 1947. Report on a collection of mammalian bones from archeologic cave-sites in Coahuila, Mexico. Journ. Mammalogy, 28(2):147-165, 1 pl., 2 figs., 1 table. GÜNTHER, A. 1885. Biologia Centrali-Americana. Reptilia and Batrachia. Chelonia, pp. 1-18. HAMILTON, R. D. 1947. The range of _Pseudemys scripta gaigeae_. Copeia, 1947(1):65-66. HARTWEG, N. 1939. A new American _Pseudemys_. Occas. Papers Mus. Zool. Univ. Michigan, no. 397, 4 pp. LEGLER, J. M. 1960. Natural history of the ornate box turtle, _Terrapene ornata ornata_ Agassiz. Univ. Kansas Publ., Mus. Nat. Hist., 11(10):527-669, pls. 15-30, 29 figs. 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. SHANNON, F. A., and SMITH, H. M. 1949. Herpetological results of the University of Illinois field expedition, spring 1949. I. Introduction, Testudines, Serpentes. Trans. Kansas Acad. Sci., 52(4):494-509. 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. WILLIAMS, E. 1956. _Pseudemys scripta callirostris_ from Venezuela with a general survey of the scripta series. Bull. Mus. Comp. Zool., 115(5):145-160, Pls. I-III, 4 figs. _Department of Zoology and Entomology, University of Utah, Salt Lake City, Utah, Transmitted May 23 1960._ 28-3860