Geographic distribution and phenotypic variation of Tantilla boipiranga Sawaya & Sazima, 2003 (Serpentes, Colubridae)

Abstract

The discovery of new specimens of Tantilla biopiranga from some new sites revealed morphological and chromatic variations from that previously known only based on Serra do Cipó, south part of Espinhaço Mountain Range, Minas Gerais State, Brazil. The new sites are Ouro Preto and Alvorada de Minas, both in Minas Gerais State, and also in the same geographic complex of Espinhaço Mountain Range. This geographic distribution indicates that it is a probably endemic species to this region. The following morphological and chromatic variations were obtained from specimens from Ouro Preto: presence of a longitudinal vertebral black line, evident or vestigial in some individuals; a cephalic black region extending along the temporal region or a black spot in this region; presence of a narrow yellow collar on the neck after the black collar; smaller number of ventral scales (143-147 in males, 153-158 in females); smaller number subcaudal scales (56-67 in males, 51-58 in females). These variations allowed to differentiate two distinct populations of this species, one from Serra do Cipó and another from Ouro Preto. Based on our data we propose: T. boipiranga shows different metapopulation, with different states of characters in each population, or, the species presents a single population in the south of Espinhaço Mountain Range, presenting clinal variations in the characters analyzed. From the variations described, a new diagnose to T. boipiranga is presented.