Integrative Taxonomic Assessment of Two Atractus (Serpentes: Dipsadidae) from Mérida Andes, Venezuela

Recently, the nominal species Atractus meridensis was considered a junior synonym of Atractus erythromelas, both species being endemic to the cordillera de Mérida in Venezuela. Here, its taxonomic status is resolved through the examination of the original descriptions, available type specimens, and an extensive comparison of additional museum material. In this review, we provide a new morphological–phylogenetic approach regarding its diagnosis and description for each species, including a model of its current distribution, which demonstrates its allopatric distribution. Both sleepyhead snakes are considered mimetic, but A. erythromelas exhibits a polymorphic color pattern with at least five known morphs, while A. meridensis is dichromatic with only two known color patterns. According to the IUCN, both taxa should be included in the Vulnerable category according to criteria B2abi,ii,iii,iv.