Genetic divergence and evolution of reproductive isolation in eastern mediterranean water frogs

Water frogs [genus Pelophylax (Rana)] that occur around the eastern Mediterranean Sea provide an opportunity to study early stages of speciation. The geography of the eastern Mediterranean region has changed dramatically since the Middle Miocene as a result of motions of adjoining lithospheric plates and regional-scale vertical crustal motions (uplift and subsidence). For several hundred thousand years between 6 and 5 million years ago (Mya), the Mediterranean basin was isolated from the Atlantic Ocean, and became desiccated (the Messinian Salinity Crisis; MSC). Geological data suggest that the endemic water frog lineage on Cyprus was isolated by the flooding of the Mediterranean basin by salt water at the end of the MSC, circa 5.5–5.3 Mya