SYSTEMATIC REVISION OF “CANIS” ENSENADENSIS AMEGHINO 1888 (CARNIVORA, CANIDAE) AND THE DESCRIPTION OF A NEW SPECIMEN FROM THE PLEISTOCENE OF ARGENTINA

Abstract

The fossil record of foxes in South America is very rich, with almost all extant South American species recorded. Currently, three fossil species are known in the Plio-Pleistocene of South America: “Dusicyon” cultridens, Dusicyon avus and “Canis” ensenadensis. In the present work we reviewed the systematics of “Canis” ensenadensis from the Pleistocene of Buenos Aires province using both qualitative and quantitative approaches. We also described a new fossil specimen (MCA 2082) from Buenos Aires province (Argentina) that shares some similarities with “Canis” ensenadensis. We compared the fossil specimens with a large sample of specimens that includes the living species Lycalopex gymnocercus, L. culpaeus, Cerdocyon thous, L. fulvipes, L. vetulus, L. sechurae and Atelocynus microtis. We performed a Principal Component Analysis using mandibular and dental measurements, and then a geometric morphometry analysis using photographs of the lateral view of the mandible. Our results indicate that “Canis” ensenadensis is a valid species and it should be included in the genus Lycalopex. We also conclude that MCA 2082 is a member of the genus Lycalopex, probably belonging to the species L. ensenadensis. These results suggest that the biochron of L. ensenadensis reaches the Lujanian Age. Even if our assignation of MCA 2082 is incorrect, this specimen represents a different taxon from those already described for the Lujanian, thus the diversity of foxes during the Lujanian is greater than previously known.