Effects of Quaternary climatic oscillations over the Chacoan fauna: phylogeographic patterns in the southern three-banded armadillo Tolypeutes matacus (Cingulata: Chlamyphoridae)

Abstract

The southern three-banded armadillo, Tolypeutes matacus, is one of the most representative species of the South American Chaco region. Thesusceptibility of this species to climatic changes and its good number of paleontological records has led to the study of their range dynamicsfor untangling the effects of Quaternary oscillations. These studies yielded contradictory results, suggesting expansion processes under op-posite conditions: some during glacial periods and others during interglacial periods. Here, we assess the population structure of T. matacusin Argentina based on mitochondrial genes, and estimate demographic and spatial dynamics that contribute to unveiling the evolutionaryprocess that moulded its biogeography. We found no clear phylogeographical breaks, although there were differences in the composition andfrequency of haplotypes between the northern and southern localities studied. Demographic inferences indicate that the species has under-gone population and range expansion processes. The higher diversity found in the north and the spatial diffusion analysis allow us to infer anorth–south direction of this expansive process. Our results yield essential evidence for disentangling the evolution of this Chacoan specieslinked with Quaternary climates and provide genetic information about its populations that should be taken into account for the conservationof this threatened mammal.