Análisis ecomorfológico del cánido hipercarnívoro Theriodictis platensis Mercerat (Mammalia, Carnivora), basado en un nuevo ejemplar del Pleistoceno de Argentina

Abstract

"Theriodictis was part of a South American clade of canids showing hypercarnivorous characters such as large carnassial teeth lacking the metaconid and the hypoconid, wide palate, and small postcarnassial molars. This genus comprises two species: T. platensis Mercerat, from the pampean region of Argentina, and T. tarijensis (Ameghino) from Tarija, Bolivia. Both are restricted to the Ensenadan Age, early to earliest late Pleistocene (Biozone of Tolypelltes pampeus, 1.8 to 0.5 Ma). The discovery of an almost complete skeleton of T. platensis (MLP 96-IX-1-I) permits an ecomorphological analysis. This approach uses principal component and discriminant function analyses, as well as multiple regression analysis for estimating ecomorphological adaptations and body mass in extinct canids. The body mass estimated for T. platensis was ~37 kg. The craniodental morphology of this species was similar to that shown by extant hypercarnivorous canids whose diet includes >70% of herbivores and other carnivores. The potential ungulate prey of T. platensis included camelids (Lama sp.), cervids [Epieurycerus truncus Ameghino, Antifer ensenadensis (Ameghino)], equids [Equus (Amerhippus) sp., Hippidion devillei (Gervais)], and tayassuids (Catagonus metropolitanus Ameghino), as well as giant rodents (Neochoerus sp.). mesotherids (Mesotherium cristatum Serrés), and giant dasypodids [Eutatus seguini (Gervais), Propraopus grandis Ameghino, Pampatherium sp.].