Singing on key: An integrative taxonomic revision of barking geckos (Gekkonidae: Ptenopus) with six additional species and keys for morphology and advertisement calls

Abstract Barking geckos, Ptenopus Gray, 1866 are burrowing geckos that occur across the xeric regions of southern Africa. They possess unique vocal abilities, with males producing loud advertisement calls to attract females. The taxonomy of the genus has remained stable for six decades, with three recognised species: Ptenopus garrulus (Smith, 1849), P. kochi Haacke, 1964, and P. carpi Brain, 1962. Within P. garrulus , two subspecies have been recognised since 1935: the nominotypical form ( P. g. garrulus ) and P. g. maculatus Gray, 1866. A recent phylogenetic analysis of the genus found that it contains eight to ten putative species. We used an integrated taxonomic approach to delimit a total of nine species, including evidence from phylogenetics, ecology, calls, and morphology. Ptenopus g. maculatus is elevated to full species, thereby restricting the geographic range of P. garrulus sensu stricto to the greater Kalahari. Additionally, four new species are named which were previously included in ‘ P. g. maculatus ’: Ptenopus adamanteus sp. nov. from the southern Namib Desert, P. circumsyrticus sp. nov. from the central Namib Desert, P. kenkenses sp. nov. from the northern Nama Karoo, and P. australis sp. nov. from southern Nama Karoo. As a result, the range of P. maculatus sensu stricto is restricted to the central northern Namib Desert. Furthermore, one new species previously included in P. carpi is named P. sceletus sp. nov. from the Skeleton Coast (northern coastal Namib Desert), thereby restricting the range of P. carpi sensu stricto to a small strip of coastal Namib Desert between the Swakop and Kuiseb rivers. The Namib Desert is the centre of diversity for the genus Ptenopus , containing seven of the nine species including the oldest divergent lineages. Two species-level keys are provided: a morphological key and a unique bioacoustic key to the advertisement calls.