Patagonia, the southernmost part of the American continent encompasses approximately one million km2, and although the majority of this area corresponds to the steppe biogeographic region, the Northwestern part of Patagonia also includes Monte and Altoandina regions. This area includes western Río Negro, Neuquén and southern Mendoza provinces in Argentina and neighboring areas of Chile and adjacent southern Andes. This region is geographically very complex, with high mountains and steep volcanic peaks, deep valleys, and isolated high plateaus, product of Andes orogeny and subsequent history of volcanism coupled with a long history of glaciations that produced pronounced climatic changes along the most recent million years. During the last years, lizard field surveys in this region have shown that it constitutes a biodiversity “hotspot” for this fauna, and several microendemic species have been described for some high plateaus isolated areas, which are the most vulnerable to extinction due to climate change. Lizards have been proposed as model organisms for a variety of studies and particularly the South American genus Liolaemus is emerging as a model system itself. This genus is the most prominent of northwestern Patagonia, and almost half the lizard species from this area are endemic. Based on several genes sequence data and morphological data I have generated during my first 3 years of PhD program, I would like to implement several new phylogeographic statistical methods as well as new phylogenetic and areas for conservation methods to: 1-test hybridization hypotheses as the origin of biodiversity and 2-accurately delineate species boundaries, 3-propose high priority conservation areas and highlight species at high extinction risk due to climate warming.