Diversity of Sand Snakes (Psammophiidae, Psammophis) in the Horn of Africa, with the description of a new species from Somalia

Abstract

The biological diversity of the Horn of Africa is one of the least studied in the world. Yet the Horn supports rich communities of species that are mostly endemic to the region. Here we study the diversity of Sand Snakes (Psammophis) in East Africa, their phylogeny and systematics. Previous studies have unveiled several cryptic and potentially undescribed species of Psammophis that occur in the Horn and their taxonomic status has remained unclear to this day. We used sequence data from two mitochondrial and one nuclear genes to reconstruct the phylogeny of the genus, in which we included newly obtained samples of six different Psammophis species from Somalia, Ethiopia, Eritrea, Sudan, and Egypt. Our aim was to assess the status of some of the undescribed species, examine the level of intraspecific genetic variation within individual species, improve our understanding of the species distributions, and contribute to the taxonomy of the genus. Our results confirm the existence of two undescribed species, one in eastern Somalia, which we formally describe as new, and one in southern Ethiopia that we refer to as Psammophis cf. sudanensis in accordance with previous studies. Further, we provide first genetic data for the nominotypical subspecies of P. punctulatus and confirm the species status for its subspecies P. trivirgatus. In addition, we provide new genetic data for P. tanganicus from Ethiopia and Somalia, and range extension records for P. rukwae from Eritrea and Ethiopia and for P. aegyptius from Somalia. Our findings contribute considerably to our understanding of the diversity and distribution of Psammophis in East Africa.