Phylogeography and Past Distribution of Peripheral Individuals of Large Hairy Armadillo Chaetophractus villosus

The fossil and molecular evidence suggests that the area of origin of the Hairy Armadillo Chaetophractus villosus was the central Pampas region of Argentina, with a current distribution that includes Bolivia, Paraguay and Chile. We studied the evolutionary history of peripheral individuals of C. villosus using phylogeographic approaches and potential distribution models for the Holocene. We sequenced a segment of the mitochondrial DNA control region in 22 individuals with a peripheral distribution that inhabit the western limit of its current distribution in Chile, which was compared with Argentine sequences of the central distribution. The results show that the peripheral individuals studied have less genetic polymorphism than populations in the central distribution. All Chilean sequences were grouped in the haplotype C, which is dominant in Patagonian populations of Argentina. The potential distribution model predicts that during the Holocene the areas in which the peripheral populations of Chilean C. villosus are currently distributed presented medium–high habitability conditions for the species. Our results are consistent with the center–periphery model, showing a decrease in genetic diversity in peripheral areas of the distribution of C. villosus. It is probable that the low genetic diversity of the peripheral population is related to recent population establishment by dispersion from adjacent Argentine Patagonian populations. Peripheral populations such as those studied can have small population sizes; however, they can remain stable and have high survival rates during climatic oscillations, acting as important relics for the conservation and evolutionary potential of the species.