CONICET | Buscador de Institutos y Recursos Humanos

The Cerro Azul Formation (La Pampa Province, Argentina) comprises a rich vertebrate fauna of small mammals dominated by notoungulates and rodents. The fauna pertains to the late Miocene specifically to the Huayquerian Stage/Age. Taphonomic analysis of micromammals from Estancia Ré locality evidenced that the faunal assemblage was accumulated by the activity of a predator. This assemblage was compared with others from the Cerro Azul Formation in Telén and Caleufú localities (La Pampa Province), previously interpreted as products of predator activities. These microfossil accumulations differ from assemblages attributed to feces and pellets produced by modern predators (nocturnal and diurnal bird raptors and carnivore mammals). However, due to their anatomical representation, degree of bone breakage, and presence of tooth marks, they are interpreted as accumulations of uneaten prey remains discarded by the predator. The predator involved could not be determined with certainty, although the presence of tooth marks in some skeletal remains and the presence of coprolites in Telén and Caleufú suggest that it could be a carnivore mammal. Similarities in the accumulation mechanism, patterns of preservation, and sedimentary contexts in the three assemblages, support the recognition of a new taphonomic mode, termed "leftover prey remains".