Life on the Rocks: Shallow Genetic Structure in a Narrowly Endemic Lizard from the Argentine Puna

ROBERTSON J; RHYMER R; AKOPYAN M; SANABRIA E.; QUIROGA L.; ESPINOZA R.

New Orleans

Congreso; Joint Meeting of Ichthyologists and Herpetologists; 2016

Kansas State University

Narrowly endemic species often have small geographic ranges, which can have implications for population genetic structure and gene flow. Phymaturus extrilidus (Liolaemidae) is a recently described rock-dwelling lizard from the high-elevation (>3100 m) desert region (Puna) of San Juan, Argentina. The known geographic range of this species is limited to three mountainside passes covered by rocky outcrops and separated from each other by 1?3 km of largely unsuitable (boulder-free) habitat. Demographic data based on a 2-y mark?recapture study at one site indicated a strongly female-biased adult population (~2F:1M), suggestive of male-biased dispersal. We examined the population genetic structure of 65 individuals captured at the three sites using 12 microsatellite loci. We found weak genetic structure across the three sites, with low but significant estimates of FST (0.01?0.02). STRUCTURE analyses indicated that lizards from these sites belong to a single genetic deme. Combined, the population genetic analyses indicate that sites are not demographically isolated despite the seemingly inhospitable intervening habitat. Next we amplified a portion of the mtDNA NADH4 gene from 5?7 individuals per site to examine the evolutionary history of the populations. Our sampling revealed five unique haplotypes with few nucleotide differences. The two most common haplotypes (frequency of 66% and 14%) were present at all sites, indicating that this narrow endemic species has undergone a recent evolutionary expansion with historical admixture across its range. A field-based study of migration and dispersal patterns is needed to determine the extent of current gene flow among sites.