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.
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.