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.
Ecnomidae
The Ecnomidae taxonomy has been problematic, Ecnomidae was first described (Ulmer 1903) as a subfamily of Hydropsychidae, and later as a subfamily within Psychomiidae. The family Ecnomidae is now accepted as monophyletic beside its sister-group Polycentropodidae. The Ecnomidae contain at least 9 genera with the most diversity found in the genus "Ecnomus". Currently, a total of 375 species are described. In recent years, several new species has been discovered, mainly from the Oceania region. Other phylogenetically distinct genera exist which have not been scientifically described yet.All Ecnomidae genera are restricted to the Southern Hemisphere except the genus "Ecnomus", which is widely distributed. This means the group of may have a Gondwanan origin.