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

Priscila S Carvalho,Diego J Santana,Nelson J Da Silva,Hussam Zaher

doi:10.7717/peerj.10073

Abstract

BackgroundStudies 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.MethodsWe 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.ResultsAccording 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.

Highlights

Species are considered lineages with distinct evolutionary histories (De Queiroz, 2007)
We evaluated the taxonomic status of Hydrodynastes gigas and Hydrodynastes melanogigas by sequencing two mitochondrial and two nuclear genes for 32 individuals belonging to the two species
The uncorrected p-distance for both the mtDNA 16S and Cytb showed low genetic differences (0.01% and 0.2%, respectively) between the lineages of H. gigas and H. melanogigas

Summary

Introduction

Species are considered lineages with distinct evolutionary histories (De Queiroz, 2007). A morphological and molecular study of Hydrodynastes gigas (Serpentes, Dipsadidae), a widespread species from South America. Many species are described based solely on morphological patterns, which could merely reflect interpopulational variation, instead of evidence of lineage separation (e.g., Brusquetti et al, 2014; Mângia et al, 2020). 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. 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

Methods

Results

Discussion

Conclusion