Undescribed and imperiled vertebrate biodiversity near an American urban center.

Urban expansion threatens biodiversity hotspots and endemic species. In this study, we describe two imperiled new species of fishes belonging to the vermilion darter (Etheostoma chermocki) complex. These new species are restricted to individual stream systems surrounding the city of Birmingham, Alabama, USA, and are at risk of extinction due to anthropogenic development. Genomic species delimitation reveals that members of this species complex, which differ subtly but consistently in meristic counts and coloration, show high levels of genomic divergence and little gene flow among them. These brilliantly coloured species, whose diversification tied to the erosional dynamics of the Black Warrior River basin, exemplify the imperiled, yet undescribed, species diversity within an urban landscape in the southeastern North American biodiversity hotspot.