Chance, luck and a fortunate finding: a new species of watersnake of the genus Helicops Wagler, 1828 (Serpentes: Xenodontinae), from the Brazilian Pantanal wetlands.

We describe a new watersnake of the genus Helicops based on a single specimen found in the northern limit of the Brazilian Pantanal. Immediately after collection, the unique features of color pattern and head proportions prevented us to attribute this specimen to any other congener. Further comparisons revealed that the combination of entire nasal scales, a distinctively acuminate snout, high dorsal and supralabial counts, as well as a dorsal pattern with chain-like spot rows and a venter with vivid and peculiar orange markings confirmed that the specimen represented a new species. Molecular data supported our morphological conclusion recovering the new species deeply nested within Helicops terminals, sister to a clade composed by H. carinicaudus and H. nentur. Our discovery represents a rare instance of a snake species restricted to the Brazilian Pantanal, but we refrain from considering it a Pantanal endemic until further records allow more considerations on distributional patterns.

Diagnostic clarification, new morphological data and phylogenetic placement of Amphisbaena arenaria Vanzolini, 1991 (Amphisbaenia, Amphisbaenidae).

Several decades ago, Vanzolini (1991) described Amphisbaena arenaria Vanzolini, 1991 based on a single individual (MZUSP 65817) collected at Raso da Catarina, a large flat sandy deposit at the southern bank of São Francisco River. In the same paper he described A. frontalis Vanzolini, 1991 based on specimens collected at another sandy area, at the northern bank of São Francisco River, both in Bahia state, Brazil. As conflicting values are presented throughout his paper, the diagnosis of A. arenaria still needs clarification. We here comment on these differences and re-diagnose A. arenaria including new topotypic material, providing its phylogenetic placement and a new state record.