The short-faced bears (Ursidae, Tremardinae) of Venezuela

LEOPOLDO HECTOR SOIBELZON; RINCÓN, A.

Córdoba

Congreso; 9° CONGRESO ARGENTINO DE PALEONTOLOGÍA y BIOESTRATlGRAFÍA; 2006

The [¡rst record of a Tremarctinae bear in Venezuela was made by Royo y Gomez in 1960. Since thispublication, few new specimens were collected but not reported. The objective ofthis contribution is to discusst4e taxonomy, bioestratigraphy, and biogeographic implications of these records. The bear genera that constitutethe subfamily Tremarctinae are distributed exclusively in America. In South America the only fossil genusrecorded is Arctotherium which comprises five species: A. angustidens, which is restricted to the Ensenadan(Early-Middle Pleistocene) of Argentina and Bolivia; A. vetustum, registered onIy in the Bonaerian (MiddlePleistocene) ofBrazil andArgentina; two Bonaerian and Lujanian (Middle Pleistocene-Early Holocene) species,A. bonariense (recorded onIy in Argentina), and A. tarijense (distributed in Argentina, Uruguay and Chile); andA. wingei, registered with certainty only in the Lujanian (Upper Pleistocene-Lower Holocene). After the presentstudy we conclude that (1) the onIy species recorded in Venezuelais A. wingei, and (2) all known specimens comefrom the Lujanian. Outside Venezuela, this species is recorded in Bolivia and Brazil but without accuratestratigraphic provenances. Although A. wingei is one of the most plesiomorphic species of Arctotherium, it hasnot been recorded in sediments older than Upper Pleistocene. That could be explained as a species's preferencefor low latitude, tropical or subtropical environments, where the Lower Pleistocene continental sediments arepoorly represented.114