Brown-Banded Watersnake

distribution

Distribution. Widespread in the northern portion of South America, occurring in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Trinidad, and Venezuela (Plt. 276 A). In Brazil, widespread in Amazonia, Chiquitano Dry Forest, Cerrado, Caatinga, and northern portion of the Atlantic Forest (Plt. 276 A), mostly at low elevations (Plt. 276 B). Observed in the field in streams in forest (Martins and Oliveira, 1998) and savanna (Dal Vechio et al., 2013).

Atlas of Brazilian Snakes: Verified Point-Locality Maps to Mitigate the Wallacean Shortfall in a Megadiverse Snake Fauna

Diagnosis

Helicops angulatus can be distinguished from all its congeners, except H. scalaris and H. apiaka by having subcaudal keels, 17–20 dorsal scale rows at mid-body (compared to 19 in H. gomesi ; 21–27 in H. hagmanni ; 23–25 in H. pastazae ) and 103–123 ventrals (compared to 125–132 in H. gomesi ; 117–138 in H. hagmanni ). From H. scalaris , it differs in having no intergenials (for information on references, see Suppl. material 3; for summarised pholidosis information of the examined specimens, see Tables 1, 2). For differentiation from H. apiaka , see identification of H. apiaka.

Distribution and identification of the species in the genus Helicops Wagler, 1830 (Serpentes, Colubridae, Xenodontinae)

Distribution

The distribution of H. angulatus extends over nearly the complete northern part of South America. As shown in Fig. 1a, the distribution range extends from Columbia to the east coast of Brazil and from Venezuela and offshore islands to the Brazilian Province of Sao Paulo and Bolivia.

Distribution and identification of the species in the genus Helicops Wagler, 1830 (Serpentes, Colubridae, Xenodontinae)

Helicops angulatus (Linnaeus 1758) Linnaeus 1758

Helicops angulatus (Linnaeus, 1758) “Cobra-d’água” (Figs. 15.5 and 28.2) It was recorded in the states of Piauí, Ceará, Paraíba, and Sergipe. The records in Caatinga are in low altitudes (up to 560 m elevation). This species also occurs in the Amazon Forest, Cerrado, and Pantanal regions (Cunha & Nascimento 1978; Martins & Oliveira 1998; Marques et al. 2005; Nogueira et al. 2010). It inhabits arboreal and bush caatinga next to the eastern Atlantic Forest and relictual moist forests in highland areas. As other congeneric species, it is an aquatic snake and consequently, its distribution is determined by the presence of water bodies and dependent on the dranage system (see Rodrigues 2005). It is diurnal and nocturnal, and feeds mostly on frogs and fishes (Marques et al. 2005; Scartozzoni 2009).

Diversity, natural history, and geographic distribution of snakes in the Caatinga, Northeastern Brazil