Phylogeny of the tribe Tachymenini Bailey, 1967 (Serpentes, Dipsadidae, Xenodontinae)

Abstract

Caenophidia systematics ("advanced" snakes) has been impelled in recent years, coincidently with the development of molecular biology, resulting in crucial taxonomical changes for the group. Intra and intertribal evolutionary relationships of the Xenodontinae, and its association with other Dipsadidae, are incipient and the monophyly of several groups are yet instable. The current project addresses the study of the phylogenetic relationships among the members of the tribe Tachymenini (Dipsadidae, Xenodontinae) and its arrangement within Dipsadidae, one of the most representatives groups within Caeonophidia. Morphological and molecular data will be employed in order to compile a comprehensive set of information concerning the tribe's evolutionary relationships. The main objectives herein proposed are: 1) to test the hypothesis of relationship among Tachymenini members, for a better comprehension among genera relationships and to validate taxonomical changes; 2) to test the positioning of Tachymenini within the Xenodontinae. The phylogenetic relationships will be inferred through the analysis of morphological data and gene sampling from four mitochondrial and six nuclear genes. The analysis will be performed following the cladistics methodology and maximum parsimony as the phylogenetic inference method, in a comparative context with probabilistic methods. The assembled results will allow to infer a better resolution of evolutionary patterns from the Tachymenini, to elucidate the relationships between the Xenodontinae and, ultimately, will assist with the understanding of diversification patterns of Neotropical snakes. (AU)