The Zagros Mountains acting as a natural barrier to gene flow in the Middle East: more evidence from the evolutionary history of spiny-tailed lizards (Uromasticinae: Saara)

We investigated the phylogeographic structure of the genus Saara and studied whether the Zagros Mountain ranges influence the gene flow and dispersal at the landscape scale between the Iranian Saara species, including S. asmussi in the central Iranian plateau and S. loricata in the Mesopotamian lowlands. Phylogenetic analyses clearly show three well-supported species, including S. loricata, S. asmussi and S. hardwickii, that are distinct from Uroinastyx species. The S-DIVA and BBM analyses demonstrate that species of Saara originated from an ancestor somewhere in the Iranian Plateau and then dispersed to its current geographical range. Our results indicate that the separation of S. loricata from S. asmussi coincides with the orogenic events of the Zagros Mountains during the Pliocene, and thus it may show a vicariance event. Diversification within populations of S. loricata and S. assmussi are estimated to have occurred during the Pleistocene. The haplotype network indicates one haplogroup for each of the Iranian Saara species. Population genetic analyses shows signals of demographic expansions at the beginning of the Holocene for S. loricata. Our results support the hypothesis that the Zagros Mountains act as a barrier for gene flow and Quaternary climatic oscillations affected intraspecific genetic divergences of S. loricata and S. asmussi.

Automated summary

Our study revealed that Saara species originated from an ancestor in the Iranian Plateau and dispersed to their current geographical range, with the separation of S. loricata from S. asmussi coinciding with orogenic events in the late Pliocene. Intraspecific genetic divergences within populations occurred during the Pleistocene.