A NEW SPECIES OF TUCO-TUCO, GENUS CTENOMYS (RODENTIA, CTENOMYIDAE) FROM PATAGONIAN CHILE

A new species of tuco-tuco, genus Ctenomys, is described from Chilean Patagonia. Multivariate analyses of external and cranial measurements discriminate between this and the allopatric C. colburni. Chromosomal and qualitative cranial characters confirm the specific distinction of the new taxon (2n = 28). Although morphologically most similar to nei ghboring C. colburni (2n = 34), chromosomal data indicate that the new taxon is more closely allied with the C. maulinus group (2n = 26). Di agnostic characters of the new species include relatively small size, silvery-white hairs on the dorsal surface of the hind feet, a roughly linear alisphenoid-presphenoid bridge, a single large lateral alisphen oid foramen, and a round and large post-alisphenoid canal.