Taxonomic status and morphological variation of Hydrodynastes bicinctus (Hermann, 1804) (Serpentes: Dipsadidae)

Abstract

Hydrodynastes bicinctus was described with no type material or locality and it has two subspecies currently recognized that are not taxonomically well defined. We tested the validity of the two subspecies through meristic, morphometric, and color pattern characters. Two apparently distinct color patterns of H. bicinctus were noticed, one from the Cerrado open formations and the other from the Amazon rainforest. These aforementioned patterns, however, exhibited a high degree of geographic overlap and many specimens showed a blended pattern. Based on these results we propose synonymizing H. bicinctus schultzi with the nominal taxon. Furthermore, we designate a neotype for the species, present data on geographic distribution, and provide morphological descriptions of the hemipenis, cephalic glands, and skull.

Roadkill records of reptiles and birds in Cerrado and Pantanal landscapes

“…3). Previously, this species has only been reported in the Cerrado plateaus and Amazon rainforest (Murta-Fonseca et al 2015, Ferreira et al 2017. Eight reptile species were recorded as roadkill for the first time in Brazil (new roadkill records, NRR): Hydrodynastes bicinctus, Amerotyphlops brongersmianus, Bothrops mat- Bearded Toadhead Turtles are easily recognizable, despite doubts about subspecies occurrence within the geoffroanus complex (Souza 2005).…”

“…Based on the most recent reptile checklist from Mato Grosso do Sul (Ferreira et al 2017), which encompasses a broad inventory of the Pantanal and sur-rounding plateaus, our record of Hydrodynastes bicinctus (Dipsadidae) in the Pantanal basin is the first geographic record (FGR) for this species (Table 2). Hydrodynastes bicinctus has only been reported in open areas of the Cerrado plateaus and Amazon rainforest (Murta-Fonseca et al 2015). In Mato Grosso do Sul, H. bicinctus was only reported in the municipalities of Bataguassu, Ivinhema, Paraíso das Águas, Três Lagoas, and Santa Rita do Pardo (Murta-Fonseca et al 2015), while the reptile checklist from the state (Ferreira et al 2017), which included areas near the BR-262 between Campo Grande and Corumbá, did not make any record of this species.…”

Snakes as a model for measuring skull preparation errors in geometric morphometrics

“…Therefore, to standardize the acquisition of images and to avoid the wide-angle distortions problem, skulls must be positioned in the centre of the field of view in both techniques (Zelditch, Swiderski & Sheets, 2004). Taking the above precautions into account, both techniques represent efficient methods to access information on skull morphology of vertebrates and are largely used in the literature (Cardini & Elton, 2007;Cardini et al, 2015;Hamdan & Fernandes, 2015;Murta-Fonseca, Franco & Fernandes, 2015;Murta-Fonseca & Fernandes, 2016;Souto et al, 2017).…”

Distribution extension for Hydrodynastes melanogigas Franco, Fernandes & Bentim, 2007 (Serpentes: Dipsadidae: Xenodontinae) in the Araguaia-Tocantins basin, Brazilian Cerrado

“…The snake genus Hydrodynastes is associated with aquatic environments and occurs in some river basins of South America (Franco et al 2007, Murta-Fonseca et al 2015. It is currently represented by three species: H. gigas (Duméril, Bibron & Duméril, 1854), H. bicinctus (Hermann, 1804), and H. melanogigas Franco, Fernandes & Bentim, 2007.…”

“…It is currently represented by three species: H. gigas (Duméril, Bibron & Duméril, 1854), H. bicinctus (Hermann, 1804), and H. melanogigas Franco, Fernandes & Bentim, 2007. In Brazil, Hydrodynastes gigas and H. bicinctus have wide geographical distributions, occurring mainly in rivers of the Amazon and Cerrado biomes (Franco et al 2007, Murta-Fonseca et al 2015. In contrast, H. melanogigas is known only from few localities in the Tocantins river basin in the Brazilian states of Tocantins (municipalities of Lajeado, Palmas, and Porto Nacional) and Maranhão (municipality of Carolina), all within the Cerrado biome (Franco et al 2007, Silva Jr et al 2012.…”