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 ... Read more

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. [Pg 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). Less