Mitochondrial phylogeography of the Iberian endemic frog Rana iberica, with implications for its conservation

Genetic characterization of species using phylogeographic approaches represents a basic reference to understand their evolutionary history as well as to identify conservation priorities to protect areas of particular interest regarding evolutionary potential. Even in well-studied regions such information is lacking for the majority of species, including many endemic species with reduced distribution ranges. We investigate the phylogeographic pattern of the Iberian frog Rana iberica, an endemic amphibian restricted to Central and North-Western Iberian Peninsula. Using mitochondrial sequences, we reconstruct the phylogeographic history of the species to test the effect of Quaternary climate changes on the evolutionary diversification of lineages, that is, the differentiation of mitochondrial lineages and the formation of genetic diversity melting pots, and integrate phylogeographic evidence for future conservation planning. Our results indicate the existence of 3 main mitochondrial lineages differentiated during the Upper Pleistocene. Both historical demographic analyses and climatic niche modeling show a strong effect of glacial climate changes, suggesting recurrent range contractions and expansions. Under such circumstances, differentiation took place most likely by isolation in allopatric interglacial refugia. Secondary lineage admixture in northern Portugal generated a broad mixed zone with highest nucleotide diversity. Given its particular evolutionary potential, its reduced distribution and eventual threats under current climate change scenario, conservation priorities should focus on the isolated lineage from Sierra de Guadalupe.