Multigene phylogeny, phylogeography and population structure of Podarcis cretensis species group in south Balkans

The evolutionary history of taxa with limited overseas dispersal abilities is considered to be majorly influenced by vicariant events constituting them as model organisms for the interpretation of evolutionary processes. An excellent candidate are the wall lizards of the genus Podarcis exhibiting an impressive level of genetic and morphological diversification and harboring several cases of recently discovered cryptic diversity. In this study, we investigated the effect of palaeogeographic events on the wall lizards' biodiversity patterns in the Aegean (Greece) as well as the evolutionary processes that acted both in space and time. To accomplish that we studied a group of three endemic Podarcis species (i.e., P. cretensis, P. levendis, and P. peloponnesiacus) both at the intra and interspecific levels employing mitochondrial and nuclear DNA sequence data as well as microsatellites. Furthermore, presence information coupled with bioclimatic data (i.e., species distribution modeling, and niche similarity analyses) shed light on the necessary ecological factors for the species' occurrence. These approaches revealed yet another case of cryptic diversity for this group of lizards, with the existence of two slightly overlapping lineages within P. peloponnesiacus and highly structured populations within P. cretensis. Species diversification occurred during the Pliocene with P. peloponnesiacus divergence into the two lineages dating back to 1.86 Mya. Furthermore, temperature and precipitation related environmental parameters were the most important ones regarding the current distribution of the studied species. Based on the results, we propose a more detailed phylogeographic scenario where both the paleogeography of the area and several environmental parameters have shaped the genetic diversity and the current distribution pattern of this species group.