MOLECULAR SYSTEMATICS AND BIOGEOGRAPHY OF THE MOUSE OPOSSUMS OF THE GENUS THYLAMYS

PALMA, R. EDUARDO; CANCINO, RICARDO; FLORES, DAVID., PARDIÑAS, ULYSES; RODRIGUEZ-SERRANO, ENRIQUE; BORIC- BARGETTO, DUSAN; RAMOS, SEBASTIÁN; ZEBALLOS, HORACIO; ALFARO, FERNANDO, JAYAT, PABLO

Mendoza

Congreso; 10th International Mammalogical Congress; 2009

Currently, 10 species of mouse opossums of the genus Thylamys are recognized in the southern cone of South America (Wilson& Reeder 2005). These species are distributed on and at both sides of the Cordillera de los Andes and they characterize foroccurring in open and semi-arid environments. Previous work using molecular systematic approaches have considered some of the species currently recognized. We evaluated the phylogenetic and biogeographic relationships in 60 specimens of Thylamys belonging to 9 of the recognized species by sequencing mitochondrial and nuclear genes. The reconstructed phylogeny showed that T. karimii from the Brazilian Cerrado is the most basal form, whereas the Andean T. pallidior and the Pacific coastal desert T. elegans are the most derived forms. We recovered additional well supported clades, representing the other species currently recognized. In addition, we are validating T. tatei from the higlands and lowlands of the Peruvian coast, as well as some other forms from the Argentinean Chaco. Not only species are recognized within the genus, but also subspecies, as is the case of T. elegans in its north and south distributional range, as well as in T. pallidior in both, the Andes and Patagonia. We suggest that succesive founder events from east (the Brazilian Cerrado) to west (the Andes-Pacific) in southern South America would account for the evolutionary history of this genus of mouse opossums.