Horse
Besides the horse, there are six other species of genus "Equus" in the Equidae family. These are the ass or donkey, "Equus asinus"; the mountain zebra, "Equus zebra"; plains zebra, "Equus quagga"; Grévy's zebra, "Equus grevyi"; the kiang, "Equus kiang"; and the onager, "Equus hemionus".
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.