IADIZA - GIB ACTIVIDADES Difusion Phylogeography Tympanoctomys

De Mendoza CONICET


The red vizcacha rat, Tympanoctomys barrerae, is a highly specialized octodontid rodent endemic to the central and southern aridlands of Argentina. It lives in complex burrows and occurs at low population densities in isolated patches associated to salt basins and sand dune habitats along the Monte and Patagonian deserts. To investigate the genetic structure and biogeography of this species I analyzed mitochondrial DNA control region sequences of 60 individuals occurring in 8 sites along its distribution. I found 26 haplotypes in the analysis of 800–base pair sequences. Most were restricted to single populations, although a few haplotypes were shared between populations. I found low levels of nucleotide diversity comparing with other subterranean rodents. Central populations had the lowest nucleotide diversity comparing with southern and northern populations. Molecular variance analyses indicated a slow geographic structure of the populations. Phylogenetic analyses and a haplotype network generated using statistical parsimony recovered 2 groups: A (Northern and Southern populations) and B (Central and Southern populations). Most of the populations were polyphyletic. Neutrality tests indicate no signal of population expansion. I discuss the likely southern origin of this species and suggest that topographic and climatic attributes could result in the differentiation and isolation of central populations. Furthermore, these results have implications in the conservation of isolated populations of the endangered red vizcacha rat.

Agustina A Ojeda; agustinao@lab.cricyt.edu.ar; Presentado en la IV International Conference of the International Biogeographyl Society, Enero 2009, Merida, Mexico; Partially supported through PIP CONICET 5944 and FONDECYT /1070217)

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