A New Species of Snail-Eating Snake, Dipsas Cope, 1860 (Serpentes: Colubridae: Dipsadinae), from the Atlantic Forest of Brazil

We describe a new species of snail-eating snake from two localities within the Atlantic Forest of the states of Bahia and Minas Gerais, Brazil. The new species differs remarkably from all congeners by its dorsal pattern consisting of sharply bordered triangles resembling the pattern of sympatric pitvipers, more precisely Bothrops jararaca and B. pirajai. Parameters of external morphology of the new species resemble those of the Dipsas incerta species group. Its scalation, body/head shape, and color pattern are most similar to D. alternans, a species known to occur 360 km farther south, across the Rio Doce river. The new species differs from D. alternans by exhibiting triangular dorsal blotches and a higher number of pileus blotches, by the distribution of ventral spots and morphology of the supratemporal and premaxillae, as well as in hemipenial morphology. We also provide comparisons of the new species with all sympatric and/or parapatric congeners. The finding of a new snake species in the Atlantic rainforest of southern Bahia and adjacent Minas Gerais is particularly surprising as this region is easily accessible and represents a well-sampled area regarding herpetological surveys in the last decades.