Two new African hinged terrapins (Testudines: Pelomedusidae: Pelusios)

The African hinged terrapin genus Pelusios currently contains 17 recognized species. We describe an additional new species with two subspecies from the Democratic Republic of the Congo and Tanzania. According to phylogenetic analyses of mitochondrial DNA, the new species is closely related to P. subniger, whereas three nuclear loci (C-mos, RAG2, R35) suggest a closer relationship to P. bechuanicus and P. upembae. Morphologically, the new species resembles in plastral shape P. subniger, but differs in plastral coloration in having a diffuse dark plastral pattern instead of the blotched pattern of P. subniger. The two subspecies of the new species are characterized by distinct mitochondrial clades and private alleles in the nuclear RAG2 and R35 loci. According to an examination of museum specimens and photographic records, the new species occurs largely west of the Rift Valley, while P. subniger is distributed east of the Rift Valley. Museum specimens and iNaturalist records suggest that the two species could occur sympatrically in central Tanzania. Furthermore, we found no evidence for any genetic distinctness of P. subniger from the Seychelles, supporting that the subspecies from there is invalid.