Taxonomic status of Chironius laurenti Dixon, Wiest & Cei, 1993 and of the long-forgotten Chironius dixoni Wiest, 1978 (Squamata, Serpentes)

The neotropical colubrid snake genus Chironius Fitzinger, 1826 comprises 22 species, distributed from Central America, at Honduras, to South America, in Uruguay and Argentina (Dixon et al. 1993; Hamdan & Fernandes 2015); this genus is diagnosed by the presence of 10–12 dorsal scale rows and hemipenis with single lobe and sulcus, centrally spinous, distally calyculate, acapitate and with a proximal naked pocket (Dixon et al. 1993). Chironius laurenti Dixon, Wiest & Cei, 1993 is a large sized colubrid, distributed in Bolivia, at departments of Beni, Cochabamba and Santa Cruz, and in Brazil, in Acre, Mato Grosso and Mato Grosso do Sul (Dixon et al. 1993; Miranda et al. 2014; Ferreira et al. 2017).