Moraes-Da-Silva, A., Amaro, R.C., Nunes, P.M.S., Rodrigues, M.T. and Curcio, F.F. 2021. Long known, brand new, and possibly threatened: a new species of watersnake of the genus Helicops Wagler, 1828 (Serpentes; Xenodontinae) from the Tocantins-Araguaia River Basin, Brazil. Zootaxa. 4903, 2 (Jan. 2021), 217–241. DOI:https://doi.org/10.11646/zootaxa.4903.2.3.