Aeretes

Aeretes is a genus of flying squirrel in the family Sciuridae with a single living species, the groove-toothed flying squirrel, plus two extinct fossil species; its living range is very limited, confined to China, with fossil records from Middle Pleistocene South China and Late Pleistocene sites near Beijing including Zhoukoudian. The genus is named for the distinctive grooves on its upper incisors, teeth that grew progressively higher-crowned over its evolutionary history as it specialized in eating tree bark and other fibrous vegetation.