Scutellation variation in Opheodrys aestivus

Abstract

Variation in the scutellation of Opheodrys aestivus is analyzed. North-south clines are demonstrated in the number of ventrals and caudals and the pattern of scale row reduction. Sexual dimorphism is described for the number of ventrals, the number of caudals, the locus of dorsal scale row reduction, and the locus of the umbilical scar. Taxonomic considerations result in the recognition of four races; two are newly described (carinatus and conanti); one is resurrected (majalis Baird and Girard 1853); and the nominate race is redefined. Two additional variant populations are noted but are not given taxonomic recognition.