Mitochondrial gene diversity of the mega-herbivorous species of the genus tapirus (tapiridae, perissodactyla) in South America and some insights on their genetic conservation, systematics and the pleistocene influence on their genetic characteristics

We sequenced mitochondrial genes (COI, COII, Cyt-b) of accepted Latin America tapir species (Tapirus pinchaque, T. terrestris and T. bairdii) as well as an alleged new species, T. kabomani. The mountain tapir (T. pinchaque) is a relatively rare large mammal species. Some population censuses indicate that no more than 2,000 mountain tapirs are left in the wilderness areas of Colombia, Ecuador and Peru. Our results showed that the gene diversity levels are medium to low with respect to other mammals sequenced for the same or similar genes. However, these gene diversity levels are not impoverished, which means that the genetic situation of this species is not as critical as its population censuses suggest. It will be crucial to determine the gene diversity levels in certain populations not included in the current work (the eastern and, possibly, western Andean Cordilleras in Colombia as well as the Tabaconas Namballe National Sanctuary in Peru), because they are probably the smallest populations of this species. On the other hand, the lowland tapir (T. terrestris), the species with the largest geographical distribution in Latin America, showed the highest gene diversity levels of all the other tapir species studied. Additionally, the genetic structure of T. terrestris is clearly more robust than that of T. pinchaque. Different geographic populations of both species showed different demographic trends throughout time. Our results including five samples of T. kabomani showed this taxon to be a haplogroup within T. terrestris, reducing the likelihood of T. kabomani being a new full species. Finally, we also analyzed the influence of diverse Pleistocene climatic changes on the mitochondrial haplotype diversification of T. terrestris and T. pinchaque. The Pleistocene Refugia and the Recent Lake hypotheses probably played integral roles in the evolutionary history of T. terrestris. In contrast, the Pleistocene Refugia hypothesis involving the Andes, which probably played an important part in the genetic diversification of other mammals, did not have a significant impact on T. pinchaque.