Evidencias de agregados óseos generados por depredadores durante el Mioceno tardío en los valles Calchaquíes, Tucumán y Catamarca.

NASIF, NORMA L.; ESTEBAN, GRACIELA I.; ORTIZ, PABLO E.; GAVRILOV, IGOR

San Miguel de Tucumán.

Jornada; Segundas Jornadas Geológicas de la Fundación Miguel Lillo,; 2008

Fundación Miguel Lillo

We communicate the finding of microvertebrate fossil assemblages associated in a sandy matrix. These structures come from Andalhuala Formation, that outcrops in several localities in Santa María valley. We interpretate that these accumulations were produced by the trophic activity of predators living in the Calchaquí valleys during the late Miocene. Two of these accumulations have a subspherical shape and content many cranial and postcranial fragmentary remains, highly concentred and with a very good preservation state. Some long bones are nearly completes (diaphysis more epiphyses), other bones are articulated while the remaining are irregularly disposed. Some teeth have the enamel with clear evidence of corrosion through digestion (pitting). These features permit us to consider both accumulations as pellets generated by owls. Here the first direct physic evidence of a pellet in the argentine fossil record is documented. Moreover, these structures constitute the oldest record for fossil pellets in South America. The third accumulation shows a more fragmented bony association included in a lower calcareous matrix, contains very fragmentary bones of larger unidentified vertebrates and isolated teeth that indicates a more intense destruction. These features permit us suggest that this bony accumulation shows physical damage produced by the chewing and digestive actions of a carnivore mammal. This accumulation is here considered as a fossil scat or coprolite.