Horse
The horse adapted to survive in areas of wide-open terrain with sparse vegetation, surviving in an ecosystem where other large grazing animals, especially ruminants, could not. Horses and other equids are odd-toed ungulates of the order Perissodactyla, a group of mammals that was dominant during the Tertiary period. In the past, this order contained 14 families, but only three—Equidae (the horse and related species), Tapiridae (the tapir), and Rhinocerotidae (the rhinoceroses)—have survived to the present day.
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" .