SUMMARY
The lacertid lizard Mesalina watsonana is widely distributed on the Iranian plateau where it is one of the most common lizards. However, the intraspecific variability and the phylogenetic position of this species within the genus still remain unknown. We sequenced a 715bp long fragment of the mtDNA cytochrome b gene from lizards sampled in 10 localities covering the Iranian distribution range of the species. We identified four distinct and geographically isolated clades with an average genetic divergence between them ranging from 9.8 to 13.1% (p-distance) which is comparable to the values of genetic distance commonly reported between Lacertidae species. Analyses combining data from recently published phylogeny of the genus Mesalina with our dataset confirmed the monophyly of M. watsonana. The isolation of this species from the rest of the genus points out the important role of the Zagros Mountains uplift during the Miocene. It is possible that this geological event participated on the isolation of the ancestor of M. watsonana from the rest of the Mesalina lizards and together with the upheaval of the whole Iranian plateau provided suitable environmental conditions for rapid diversification of this species.