Equus (genus)
Equus is a genus of mammals in the family Equidae, which includes horses, donkeys, and zebras. Within Equidae, "Equus" is the only recognized extant genus, comprising seven living species. The term equine refers to any member of this genus, including horses. Like Equidae more broadly, "Equus" has numerous extinct species known only from fossils. The genus most likely originated in North America and spread quickly to the Old World. Equines are odd-toed ungulates with slender legs, long heads, relatively long necks, manes (erect in most subspecies), and long tails. All species are herbivorous, and mostly grazers, with simpler digestive systems than ruminants, but able to subsist on lower-quality vegetation.
Aquila (genus)
Members of "Aquila" (excluding those moved to "Clanga" and "Hieraaetus", but including "A. fasciata/spilogaster") share two deletions in the (nuclear) LDH gene, as well as similarities in mitochondrial cyt-B gene sequence, though one of these deletions is reverted in "A. chrysaetos".Numerous fossil taxa of eagles have been described. Many have been moved to other genera, but several appear to be correctly assigned to this genus:Whether ""Hieraaetus" edwardsi" (Middle -? Late Miocene of SW Europe) belongs into "Aquila" or the hawk-eagles (if the latter are indeed distinct) is unclear. Its initial name, ""Aquila" minuta" , is preoccupied by a junior synonym of the booted eagle, "A. minuta" .