Phylogeographic structure of the subterranean rodent tuco-tuco Ctenomys talarum (Rodentia: Ctenomyidae).

ANA PAULA CUTRERA; MATIAS MORA; ENRIQUE LESSA; ALDO VASSALLO; ALEJANDRO D'ANATRO

Mendoza

Conferencia; 10th International Mammalogical Conference; 2009

International Mammalogical Society

We examined the phylogeography of the South American subterranean rodent Ctenomys talarum (Talas tuco-tuco) using mitochondrial DNA (mtDNA) control region (D-loop) sequences. We 1) assessed the genetic relationship among different populations of C. talarum in the Buenos Aires Province, Argentina, across the entire distributional range of the species and 2) analyzed how habitat history has affected the geographic genetic structure and demographic stability of these populations. The analysis comprised mitochondrial sequences (420 bp.) of 213 individuals distributed in 15 different populations along the coast from Magdalena to Pehuen Có localities (more than 900 km apart), and in the “Sierra de la Ventana” system. The results of the minimum spanning tree and AMOVAs showed high genetic subdivision and a strong phylogeographic pattern among populations of C. talarum. A complex network of haplotypes (most of which have restricted distributions) was obtained, as well as a bimodal mismatch distribution and a high portion of genetic variation attributable to differences among regions. Furthermore, pairwise FST values showed significant population differentiation among all populations studied. Nevertheless, there were shared haplotypes in populations separated by distances greater than 300 km. The overall pattern is similar to that expected under the isolation-by-distance or the stepping-stone models. Major rivers in the area appear to be associated with strong genetic differentiation in this species. In sum, the current populations of C. talarum appear to be relicts of a more extended historical distribution along the Argentinean pampas, with possible local extinctions of some inland populations of this species (e.g. in the sierras of Tandilia). These historical extinctions, however, seem not to have erased the signature of long-term stability and geographic structure of this species along the coastal and inland distribution ranges.