GEOGRAPHIC-VARIATION OF SERUM-ALBUMIN IN THE MONOTYPIC SNAKE GENUS DIADOPHIS (COLUBRIDAE, XENODONTINAE)

The ringneck snake, Diadophis punctatus (Colubridae [s.l.]: ''Xenodont inae''), is one of the most widespread snake species in North America. Thirteen subspecies currently are recognized based upon variation in several morphological characters. An antiserum prepared against the se rum albumin of the eastern subspecies, D. p. edwardsii, revealed very high levels of variation in albumin across the range of this species. The immunological distances (direct estimates of amino acid difference s) range from 0 to 25; this degree of albumin divergence typically is found between congeneric species in other vertebrates, including snake s, and indicates substantial genetic differentiation within D. punctat us. The primary division within this genus appears to separate eastern and western (including midwestern) subspecies and dates to approximat ely the Miocene. These data indicate that Diadophis may not be a monot ypic genus, but instead contains at least two genetically distinct spe cies.