PHYLOGEOGRAPHIC PATTERNS AND DEMOGRAPHIC HISTORY OF THE CTENOMYS TALARUM SPECIES GROUP (RODENTIA, CTENOMYIDAE)

CECILIA S. CARNOVALE; MATÍAS S. MORA; MARIANO L. MERINO; GABRIELA P. FERNÁNDEZ

Sao Pablo

Congreso; 66º Congresso Brasileiro de Genética; 2021

Sociedade Brasileira e Genética

Ctenomys Blainville, 1826 is the genus with the highest number of species of all known subterranean rodents. In the last decades, numerous molecular phylogenies have been inferred using multiple mitochondrial and nuclear molecular markers, which have led to the establishment of at least 8 major phylogenetic groups within the genus. The talarum group is composed by C. talarum Thomas, 1898 and C. pundti Nehring 1900, species that are closely related to each other, sharing several haplotype variants among their populations in the Pampas region of Argentina. In this study, mitochondrial control region (CR) sequences were used in order to assess the evolutionary relationships and the phylogeographic patterns among populations belonging to the talarum group, which is distributed in an extensive region in central Argentina. From 313 sequences studied (144 of them obtained in this study and 169 from GenBank database), 67 haplotypes belonging to 27 sampling locations were obtained. The studied populations showed a significant genetic structure considering the complete distributional ranges of each species. On the other hand, Bayesian analysis showed a signal of demographic expansion, followed by a gradual reduction in the effective population size that began approximately 2,000 years before present (BP), possibly accompanied by changes in the landscape during the Late Holocene. According to Pampas paleontological records and based on the results obtained here, the current populations of the talarum group are relicts of a much broader and more continuous historical distribution in the Pampas region. These results are an important report for future conservation practices, since the species C. talarum and C. pundti are currently categorized as Vulnerable and Endangered, respectively.