A new species of Apostolepis (Serpentes, Dipsadidae, Elapomorphini) from the Cerrado of Central Brazil

A morphological and molecular study of Hydrodynastes gigas (Serpentes, Dipsadidae), a widespread species from South America

BACKGROUND

Studies with integrative approaches (based on different lines of evidence) are fundamental for understanding the diversity of organisms. Different data sources can improve the understanding of the taxonomy and evolution of snakes. We used this integrative approach to verify the taxonomic status of Hydrodynastes gigas (Duméril, Bibron & Duméril, 1854), given its wide distribution throughout South America, including the validity of the recently described Hydrodynastes melanogigas Franco, Fernandes & Bentim, 2007.

METHODS

We performed a phylogenetic analysis of Bayesian Inference with mtDNA 16S and Cytb, and nuDNA Cmos and NT3 concatenated (1,902 bp). In addition, we performed traditional morphometric analyses, meristic, hemipenis morphology and coloration pattern of H. gigas and H. melanogigas.

RESULTS

According to molecular and morphological characters, H. gigas is widely distributed throughout South America. We found no evidence to support that H. gigas and H. melanogigas species are distinct lineages, therefore, H. melanogigas is a junior synonym of H. gigas. Thus, the melanic pattern of H. melanogigas is the result of a polymorphism of H. gigas. Melanic populations of H. gigas can be found in the Tocantins-Araguaia basin.

Taxonomic status of Apostolepisbarrioi Lema, 1978, with comments on the taxonomic instability of Apostolepis Cope, 1862 (Serpentes, Dipsadidae)

Apostolepis is a diverse neotropical snake genus, which has been historically subjected to poor taxonomic descriptions, largely based on either a small type series or subjective diagnoses. We evaluate the case of Apostolepisbarrioi Lema, 1978 and its intricate taxonomic history, suggesting its synonymization with Apostolepisdimidiata (Jan, 1862), and providing brief commentary on the taxonomic instability that has been plaguing the genus.