Revisión sistemática y antigüedad de Smilodontidion riggii (Carnivora, Felidae, Machairodontinae)

FRANCISCO J. PREVOSTI & LUCAS H. POMI

Revista Museo Argentino de Ciencias Naturales n. s.

MACN

Lugar: Buenos Aires; Año: 2007 p. 67 - 77

1514-5158

Abstract: Systematic review and antiquity of Smilodontidion riggii (Carnivora, Felidae, Machairodontinae).For twenty years the holotype of Smilodontidion riggii L. J. Kraglievich, supposedly recoveredfrom Chapadmalalan beds (early Pliocene), was the oldest felid record in South America. Later, it was synonymizedwith Smilodon populator Lund without clear justification. The synonymizing authors stated only that it was ajuvenile specimen of S. populator, and that it came from Ensenadan beds (late Pliocene–middle Pleistocene). Inthis paper the holotype of Smilodontidion riggii and other specimens referred to this species are reviewed,described in detail and compared with other machairodontines and large felines. The goals are to test thevalidity of this taxon, or its possible assignation to Megantereon Croizet and Jobert, S. gracilis Cope, S. fatalis(Leidy), or S. populator, and evaluate its age and provenance. Our review suggests that Smilodontidion is asynonym of Smilodon, although it could not be assigned to any species of the genus, and the validity of thespecies is not justified by the morphology of Smilodontidion riggii. The scarce and dubious geographic andstratigraphic data for MACN Pv 6802, and the information from other specimens, do not confirm a Chapadmalalanage for the taxon. Thus, the oldest South American felids are Ensenadan in age.