Two New Species of Lizards of the Liolaemus montanus Group (Iguania: Liolaemidae) from the Northwestern Uplands of Argentina

We provide descriptions for two new species belonging to the Liolaemus montanus group from northern Argentina. The new species are similar to Liolaemus nigriceps and Liolaemus multicolor. However, the new species differ from these taxa, and all other members of the montanus group, in a number of characteristics. The first new species differs from L. nigriceps in the following ways: smaller body size, dorsum of head grey, and variegated throat, and most males exhibit supernumerary precloacal pores. The second new species differs from all other members of the montanus series in having frontonasal scales forming a convex protruding area. It differs from L. multicolor in that males never show blue scales, in the lack of projecting scales on the anterior margin of the auditory meatus, in having an immaculate throat, and in the lack of supernumerary precloacal pores. The first new species occurs throughout the high elevation (3,500-4,300 m) of the puna region situated at the western edge of the southwest Salar de Arizaro (Salta Province, Argentina), an ancient hypersaline dehydrated lake. The second new species is known only from a restricted area on the hypersaline margins of the same ancient lakebed, where plant cover is quite scarce with small grassy plants, and the ground surface is salty. The discovery of these new taxa supports the hypothesis that large saline depressions, such as Salar de Arizaro, are natural vicariant barriers that favored speciation in this genus.