Bioerosion Structures on Dinosaur Bones Probably Made by Multituberculate Mammals and Dermestid Beetles (Guichón Formation, Late Cretaceous of Uruguay)

We describe the first fossil traces from the skeletal remains of dinosaurs from Uruguay, from the Upper Cretaceous Guichón Formation. We describe the first biting/gnawing fossil traces reported for Uruguay, Machichnus bohemicus Mikulás et al., 2006, probably made by small tetrapods, such as multituberculate mammals. Moreover, traces likely made by sarcosaprophagous beetles, namely Cubiculum Roberts et al., 2007, cf. Cubiculum, and cf. Osteocallis Roberts et al., 2007, are described. The presence of Cubiculum and Osteocallis supports previously proposed depositional conditions in a warm and arid to semi-arid continental environment for the referred stratigraphical unit. All traces would indicate a certain period of subaerial exposure before the definitive burial of the bones.