Aythya is a genus of diving ducks. It has twelve described species. The name Aythya comes from the Ancient Greek word αυθυια (authuia), which may have referred to a sea-dwelling duck or an auklet. Aythya shihuibas was described from the Late Miocene of China. Zelenkov (2016) transferred the species Anas denesi Kessler (2013), known from the late Miocene of Hungary, to the genus Aythya. An undescribed prehistoric species is known only from Early Pleistocene fossil remains found at , Turkey; it might however be referrable to a paleosubspecies of an extant species considering its age (see also Greater scaup).