Forbidden islands. The absence of endemics among the insular non-volant terrestrial mammalian fauna of the Red Sea

The Red Sea is a land-locked sea that is globally significant in terms of the unique biodiversity and endemism of its marine species. In contrast, the terrestrial biodiversity on its islands is poor and mainly composed of species present also on the mainland. To profile the non-volant terrestrial mammalian fauna, we reviewed all available records in the literature and report some recent captures; in particular, we point out two additional species from the Dahlak archipelago: the Northeast African spiny mouse (Acomys cahirinus) and a still undetermined shrew (Crocidura sp.). As far as we know, the only endemic vertebrates are three species of snake (Squamata, Serpentes) and perhaps one gazelle (Gazella arabica). The composition of the insular mammalian fauna of the Red Sea is olygotypic, consisting of only a few taxa, mostly anthropochorous, that are shared with the mainland of eastern Africa and/or western Arabia, and which are repeated monotonously on the few islands inhabited by mammals. A lack of endemic mammals can be explained as the result of the only recent connection of almost all the islands with the mainland during the Last Glacial Maximum and by the harsh climatic conditions that allow the survival of only a few xeric specialists.