Modifications on fossils of neoepiblemids and other South American rodents.

Modifications on the cheek teeth and dentary bone (loss of dental tissues on the extra-alveolar portion of the cheek teeth, and corrosion on the surface of the dentary bone) of fossil specimens of medium to giant South American rodents (mainly neoepiblemids) from the Neogene (Brazil and Argentina) are documented here. These features are similar to those observed in teeth and bones of small hypsodont rodents (recent and Quaternary fossils) that were subjected to digestive process by predators/scavengers. Based on comparisons, we tentatively hypothesize that acid-etching resulting from digestive processes could have caused the modifications in the specimens, providing evidence of a palaeoecological interaction between neoepiblemids (and other rodents), and predators or scavengers. [ABSTRACT FROM AUTHOR]