Comparative phylogeography of two co-distributed species of lizards of the genus Liolaemus (Squamata: Tropiduridae) from Southern Chile.

Comparative phylogeography describes the patterns of evolutionary divergence and whether or not they are congruent, in co-distributed populations of different taxa. If the populations of these taxa have been co-distributed for a prolonged time, and if the times between processes of perturbation or vicariance have been more or less stable, it is expected that patterns of divergence will be congruent in closely related species, for example because of similar biological and demographic characteristics. Liolaemus pictus and L. cyanogaster are widely co-distributed lizard species in southern Chile, occurring in a region with a complex topology. We analyzed the phylogeographic structure of the two lizard species using Cytochrome b DNA sequences to estimate their genetic structure in response to historical events. Our results suggest an evolutionary pattern of genetic diversity for each species that is consistent with the geomorphological history of the region, suggesting a complex phylogeographic history in Liolaemus species. Also, the high levels of divergence among haplotypes in several populations suggest the possibility that their origin might predate the middle Pleistocene in both species. Finally, our results are consistent with our hypothesis that two species have responded to historical events in parallel, where historical process have been sufficient to influence their phylogeographical structure (0.80 congruency between topologies). [ABSTRACT FROM AUTHOR]