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Little is known about phylogeography of armadillo species native to southern South America. In this study we describe the phylogeography of the screaming hairy armadillo Chaetophractus vellerosus, discuss previous hypothesis about the origin of its disjunct distribution and propose an alternative one, based on novel information on genetic variability. Variation of partial sequences of mitochondrial DNA Control Region (CR) from 73 individuals from 23 localities were analyzed to carry out a phylogeographic analysis using neutrality tests, mismatch distribution, median-joining (MJ) network and paleontological records. We found 17 polymorphic sites resulting in 15 haplotypes. Two new geographic records that expand known distribution of the species are presented; one of them links the distributions of recently synonimized species C. nationi and C. vellerosus. Screaming hairy armadillo phylogeographic pattern can be addressed as category V of Avise: common widespread linages plus closely related lineages confined to one or a few nearby locales each. The older linages are distributed in the north-central area of the species distribution range in Argentina (i.e. ancestral area of distribution). C. vellerosus seems to be a low vagility species that expanded, and probably is expanding, its distribution range while presents signs of genetic structuring in central areas. To explain the disjunct distribution, a hypothesis of extinction of the species in intermediate areas due to quaternary climatic shift to more humid conditions was proposed. We offer an alternative explanation: long distance colonization, based on null genetic variability, paleontological record and evidence of alternance of cold/arid and temperate/humid climatic periods during the last million years in southern South America.

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

Climatic oscillations acted as an essential factor in molding the distribution and composition of Neotropical biota. However, their effects on the South American Chaco are still poorly known. In this work, we present an updated collection of records of one of its flagship species, Tolypeutes matacus. We analyze the species' range dynamics in current and past scenarios to unveil the effects of past changes over the Chacoan biota. We construct three niches, one with current data (current niche), the other using Pleistocenic occurrence data and predictors from the Last Glacial Maximum (glacial niche), and the last one combining current and Pleistocene data to generate a multitemporal niche. Niches were projected to Current, Mid-Holocene, Last Glacial Maximum, and Last Interglacial scenarios. We obtain 398 records for the species, corresponding to current, historical, Holocene, and Pleistocene records. Current distribution occurs mainly in the currently Chaco region. For current niche reconstructions, suitable areas were smaller than those found nowadays, mainly during the Last Interglacial and Last Glacial Maximum. Holocene reconstruction recovers a distribution of suitable areas pretty similar to the present times. In contrast, glacial niche projection shows higher suitability values in the Pampean Region in all periods analyzed. Multitemporal niche projections showed similar results to those obtained from the current niche projections. Climatic oscillations seem to have significantly impacted the distribution of the species, generating retractions during past times and a period of range stability since the Holocene. Differences between niche projections suggest that Pampean populations may have evolved in different conditions than those from the Chacoan region. [ABSTRACT FROM AUTHOR]