Mid-Pleistocene Transition as a trigger for diversification in the Irano-Anatolian region: Evidence revealed by phylogeography and distribution pattern of the eastern three-lined lizard

Abstract

Past climatic events are one of the major drivers for divergence of species that could shape the present biodiversity and species dispersal patterns. Irano-Anatolian region is one of the biodiversity hotspots in the world. This region is predicted to serve various refugia during Quaternary glaciations. The eastern three-lined lizard ( Lacerta media media ) is a medium-sized lacertid species, which is originated from central Anatolian and is currently distributed almost across Irano-Anatolian region. In this study, the phylogeography, demographic history of the subspecies using mtDNA genes (cyt b , 12S and 16S) along with the species distribution models (SDMs) under past-present-future scenarios have been investigated. The results revealed that four distinct clades are well-established within the L. m. media which may intensely diverge during Pleistocene climatic fluctuations since the Mid-Pleistocene Transition (MPT). The past climate oscillations may isolate the population in various refugia throughout the Irano-Anatolian region which has been led to this divergence. The results of SDMs also indicates several localities with suitable climate conditions for eastern three-lined lizard in the region since LGM (21 thousand years ago) until the current date. This suitability can be expanded under future climate scenarios considering the existence of various low and high altitude refugia. Some conservation implications arise from the results that emphasize the importance of the region and its multiple refugia in preserving biodiversity. It can be suggested that, future conservation practices should be focused on the obtained biogeographical units such as central Anatolia, west and northwestern Iran, which encompass high levels of diversity including distinct clades within the eastern three-lined lizard.