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.
Martial eagle
The Accipitridae (hereafter accipitrids) family is by far the most diverse family of diurnal raptors in the world with more than 230 currently accepted species. As a member of the booted eagle subfamily, Aquilinae, it is one of the roughly 15% extant species of the family to have feathers covering its legs. This may be a useful feature for distinguishing these species from other eagles and raptors, as they are present even in tropical species such as the martial eagle. Under current classifications, booted eagles consist of approximately 38 living species that are distributed in every continent inhabited by the accipitrids, which excludes only the continent of Antarctica. Just under half of the living species of booted eagle are found in Africa. Studies have been conducted on the mitochondrial DNA of most booted eagle species, including the martial eagle, in order to gain insight on how the subfamily is ordered and which species bear relation to one another. DNA testing in the 1980s indicated the martial eagle was a specialized off-shoot of the small-bodied "Hieraaetus" eagles and one study went so far as to advocate that the martial eagle be included in the genus. However, more modern and comprehensive genetic testing has shown that the martial eagle is extremely distinct from other living booted eagles and diverged from other existing genera several million years ago. Genetically, the martial eagle fell between two other species in monotypical genera, the African long-crested eagle ("Lophaetus occipitalis") and the Asian rufous-bellied eagle ("Lophotriorchis kienerii"), that similarly diverged long ago from other modern species. Given the disparity of this species’ unique morphology and that the two aforementioned most closely related living species are only about as large as the bigger buzzards, the unique heritage of the martial eagle is considered even superficially evident. There are no subspecies of martial eagle and the species varies little in appearance and genetic diversity across its distribution.