Two new species of long-fingered frogs of the genus Cardioglossa (Anura: Arthroleptidae) from Central African rainforests

Abstract We describe two new frog species of Cardioglossa (Family Arthroleptidae) from Central Africa. The new species are found in the rainforests of western-central Democratic Republic of the Congo and the Republic of the Congo near the Gabonese border, respectively. We demonstrate that these species are morphologically and genetically distinct from each other and all other species of Cardioglossa. Both new species lack the dorsal hour-glass pattern present in many species of the genus, but they can be distinguished from each other and related species by distinctive colour patterns on their lateral surfaces and extremities. Both new species most closely resemble C. gratiosa, which occurs in the Atlantic coastal forests extending from Cameroon through Gabon. The new species can be differentiated from C. gratiosa by the absence of black transverse bars on all limbs or by distinctive lateral colouration. Analysis of mitochondrial ribosomal 16S DNA sequences reveals low to moderate levels (1.9–7.5%) of divergence between these new species and closely related species of Cardioglossa. The floodplains of the Congo and Ubangi Rivers may be important geographic barriers for many of these species. The occurrence of these two new lowland species in the Congo Basin reveals that the distribution and diversity of Cardioglossa in this region was underestimated. In addition, we elevate C. nigromaculata inornata to species-level status, based in part on newly available colour photographs from 1950 of specimens from the only known locality.