A REEVALUATION OF POPULATIONS OF THE CORN SNAKE ELAPHE GUTTATA (REPTILIA, SERPENTES, COLUBRIDAE) IN TEXAS

Three hundred thirty-seven preserved specimens of the corn snake Elaph e guttata from Texas, six from Arkansas, 51 from Louisiana and 20 from Missouri were examined and assigned to one of three subspecies. Based upon the number of dorsal body and tail blotches, the number of ventr als and subcaudals, the degree of ventral pigmentation and the presenc e or absence of paired subcaudal stripes, each specimen was assigned t o Elaphe guttata emoryi (great plains rat snake), E. guttata meahllmor um (southwestern rat snake) or E. guttata guttata (corn snake). When c ollection localities for the Texas specimens were plotted on a map by subspecies, the resulting distribution of the three subspecies represe nts a departure from the previous ranges for these subspecies in the s tate. Eastern specimens are newly assigned to the subspecies E. guttat a guttata, part of the central and all of the northwest specimens repr esent E. guttata emoryi, and E. guttata meahllmorum are restricted to southern Texas. A zone of intergradation exists between E. guttata emo ryi and E. guttata meahllmorum along the southern part of the Edwards Plateau and the Rio Grande River basin from Val Verde to El Paso count ies. A suspected contact between populations of E. guttata emoryi and E. guttata guttata occurs in Milam County, Texas.