A New Genus of Mexican Snakes Related to Rhadinaea

Abstract

ONE of the most interesting and surprising results of the recent intensive herpetological explorations of the valley of Cuautlapan, Veracruz, is the present diminutive species. It adds another to the already imposing list of reptilian species known from this small, rich area. For the privilege of describing it, I am indebted to Dr. E. H. Taylor, who secured the specimens and presented me with one. I wish to express appreciation also for the drawing and for advice he has offered. The species appears to be related to both Rhadinaea and Diadophis. It resembles Rhadinaea in having a capitate hemipenis, long recurved teeth, similar characters of the nasal plate (naris pierced in anterior section, bordered below by a ridge), absence of pits on dorsal scales, and certain other features. It approaches Diadophis in color pattern, character of temporals, and tail proportion. It resembles both in having smooth scales in 17 rows, normal colubrid scales on head (except temporals), and a line through the supralabials. From these two genera it differs in numerous characters. From Rhadinaea it differs in its smaller size, short tail, straight spines on hemipenis, temporals 1 + 1, in color pattern, and in the relatively slight enlargement of the posterior teeth. The absence of pits on the dorsal scales, capitate hemipenis, and nearly homogeneous teeth differentiate it from Diadophis. Despite similarity in size, body form, tail proportion and shape of head of this species and various species of Tantilla, the teeth show no relationship whatever between them. Tantilla also lacks a loreal.