Range expansion for the Critically Endangered poison-dart frog Leucostethus bilsa Vigle et al., 2020 (Amphibia, Dendrobatidae), demonstrating the importance of small forest reserves in the Ecuadorian Chocó

The Ecuadorian Chocó is a global conservation hotspot with high levels of biodiversity and endemism but is threatened by extensive deforestation. Here, we report the discovery of an additional locality for the Critically Endangered poison-dart frog Leucostethus bilsa (Amphibia, Dendrobatidae) in a privately protected forest reserve in Esmeraldas, Ecuador. This may represent a distinct IUCN location for the species, thereby downgrading its IUCN threat level to Endangered. This finding increases the extent of occurrence for L. bilsa from 0.9 to 4.78 km², and the area of occupancy from 8.0 to 16.0 km², demonstrating the importance of small forest reserves for the conservation of forest-dependent amphibians. Further surveys are warranted to determine whether the species is present in additional forest fragments in the region, the degree of connectivity, if any, between individuals inhabiting different fragments, and whether the species’ population is increasing, stable, or in decline.