Morphology and ecology of Meniscomys hippodus based on an upper jaw from the John Day formation

1 page.Aplodontiidae (mountain beavers) are common fossils found within the John Day formation of central Oregon. This paper diagnoses and identifies the species Meniscomys hippodus from a fossil jaw found at the Turtle Cove Member within the John Day formation and describes its morphology. This is done by paying particular attention to the presence of a third premolar, as well as the tribosphenic morphology of the molars. Further analysis is done on the ecology of the species. Tooth morphology can aid in identifying diet, habitat, and other forms of ecology of a specimen. Coming from the Oligocene and Miocene, evidence suggests Meniscomys hippodus to be an herbivorous and forest-dwelling rodent, which provides an insight as to the ecology and types of ecosystems that were present while this specimen was alive