Taxonomic revision of the Brazilian Atlantic Forest Atractus (Reptilia: Serpentes: Dipsadidae)

Dipsadine snakes of the genus Atractus are endemic to the Neotropical region, occurring from Panama to Argentina. Currently, the taxonomic status of most species of the genus is unclear and previous attempts of taxonomic revisions have been local in scale. In this paper we evaluate the taxonomic status of the Brazilian Atlantic Forest species of Atractus based on meristic, morphometric, maxillary dentition, and hemipenis characters. Quantitative and qualitative analyses suggest the recognition of one new species (A. caete sp. nov.) from the state of Alagoas, another (A. francoi sp. nov.) from the mountainous regions of the states of Rio de Janeiro and Sao Paulo, and the synonymy of A. kangueryensis with A. thalesdelemai. Specimens previously assigned to A. taeniatus in Argentina and Brazil are here considered A. paraguayensis. A key to the Atlantic Forest Atractus is provided and three new species groups are proposed for some cisAndean Atractus, mainly on the basis of hemipenial morphology: the A. emmeli, A. maculatus, and A. pantostictus species groups.