A Key to Identify the Snakes of Rio de Janeiro State, Brazil, along with Notes on Geographical Records.

The unequivocal identification of species helps us understand and organize life and assess the humanmediated impacts on biodiversity, allowing for an easier way to communicate biological information. However, identifying vertebrates at the species level is sometimes tricky for several reasons; therefore, compiled information and illustrative tools may help tackle this challenge. Even with questionable records, amounting to about 89 species, the state of Rio de Janeiro boasts a rich ophidiofauna with similar species in external morphology, many of which are only known from a few specimens and bear lengthy and complicated taxonomic histories. Here, we present an identification key comprising the snakes in the Brazilian state of Rio de Janeiro and a photographic catalogue for Colubridae and Dipsadidae, the most challenging families to identify due to their high richness and interspecific similarities. Due to the ongoing uncertainty about the richness and composition of snake in Rio de Janeiro, we are presenting an updated checklist of the species found in the state, along with notes on their geographical distributions. We found two species of Anomalepididae, one Typhlopidae, one Leptotyphlopidae, one Tropidophiidae, three Boidae, 15 Colubridae, 62 Dipsadidae, four Elapidae and eight Viperidae, adding up to 97 species. We then provide notable data for <i>Drymarchon corais</i>, <i>Erythrolamprus almadensis</i>, <i>Mesotes rutilus</i>, <i>Oxyrhopus rhombifer</i>, and <i>Tantilla</i> cf. <i>melanocephala</i>. This study makes distinguishing all species ascribed to Rio de Janeiro easier and offers summarized characteristics accessible to academic zoologists, wildlife managers, eco-tourists, and environmental consultants. As a result, our research adds to the efforts of numerous researchers who, in a pioneering and collaborative manner, work together to gather knowledge about this ophidiofauna.