Thanks to recent palaeontological surveys in the Miocene of southern Africa, it has become evident that, like the endemic plants of the Cape Floristic Region, there are numerous lineages of animals that originated in southern Africa during the Neogene. The spread of some of the plants and many hitherto endemic southern vertebrate lineages northwards into the tropics and beyond into Eurasia from Middle Miocene times onwards, has watered down the appreciation of endemism among the vertebrates, because several of the lineages that used to be endemic to southern Africa have subsequently become pan-African or even cosmopolitan. Among these are the ostrich, the Nile crocodile, pliohyracids, bovids and other groups, which previously were thought to have originated in the tropics or even in Eurasia. It is likely that the early onset of arid biotopes in the Namib arose well before they occurred anywhere else in Africa, and started a long period of adaptation to semi-arid, arid and hyper-arid conditions, well removed from similar biotopes in other parts of the world. The location of the Namib, in the southwestern extremity of the continent, meant that it was far from the Eurasian landmass. This factor no doubt promoted a high degree of isolation of the Namibian gene pool from that of the latter region, and thus weakened the effects of the Eurasian gene pool on southern African faunas compared with its influence on northern and eastern African ones. At the same time faunas in north and central Africa, on the one hand, and in Eurasia, on the other, were participating in relatively free genetic flow on a much more regular basis throughout the Miocene. When other parts of Africa became arid in the Late Miocene and Plio-Pleistocene, several lineages that had originated in southern Africa spread northwards and occupied those areas, replacing some of the autochthonous lineages before they themselves could adapt to the changes.