Hidden in Plain Sight: Description of a New Species of Liolaemus from the Chilean Altiplano and the True Identity of Liolaemus fabiani Yáñez and Núñez, 1983

Species of the genus Liolaemus inhabiting the high-Andean environments of northern Chile often exhibit morphological conservatism, obscuring species boundaries and generating persistent taxonomic uncertainty. One notable example involves populations historically assigned to Liolaemus fabiani from the Salar de Atacama basin. To clarify their taxonomic status, we examined type material and newly collected specimens, conducted field surveys, assessed geographic and ecological variation, and analyzed molecular and morphological evidence. Our results demonstrate that populations from the Salar de Atacama represent an independent evolutionary lineage that is clearly differentiated from L. fabiani sensu stricto. Mitochondrial data recovered both taxa in different clades within the L. montanus group and revealed a genetic divergence of 13%, comparable to interspecific distances within the group. Morphological analyses further identified consistent differences in scalation, morphometry, and coloration. Based on this integrative evidence, we redescribe L. fabiani, restrict its distribution to upland desert scrub habitats east of the Salar de Atacama, and describe a new species of Liolaemus from saline environments associated with the Salar de Atacama. These findings resolve a long-standing taxonomic problem, reveal previously unrecognized diversity within the L. montanus group, and highlight the value of integrative taxonomy for documenting biodiversity in extreme Andean ecosystems.