Hyracotherium

Hyracotherium Temporal range: 55–45 Ma PreЄ Є O S D C P T J K Pg N
BMNH C21361, the second specimen
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Perissodactyla
Family:	†Palaeotheriidae
Genus:	†Hyracotherium Owen, 1841
Species
†H. leporinum

Hyracotherium (/ˌhaɪərəkoʊˈθɪəriəm, -kə-/HY-rək-o-THEER-ee-əm; "hyrax-like beast") is an extinct genus of very small (about 60 cm in length) perissodactyl ungulates which was found in the London Clay formation. This small, dog-sized animal was once considered to be the earliest known member of Equidae before the type species, H. leporinum, was reclassified as a palaeothere, a perissodactyl family basal to both horses and brontotheres. The remaining species are now thought to belong to different genera, such as Eohippus, which had previously been synonymised with Hyracotherium.

Hyracotherium averaged 78 cm (2.5 feet) in length and weighed about 9 kg (20 pounds). It had four-hoofed toes on each front foot and three-hoofed toes on each hind foot. Each toe had a pad on its underside, similar to those of a dog. It had a short face with eye sockets in the middle and a short diastema (the space between the front teeth and the cheek teeth). The skull was long, having 44 low-crowned teeth. Although it had low-crowned teeth, the beginnings of the characteristic horse-like ridges on the molars can be seen. Hyracotherium is believed to have been a browsing herbivore that ate primarily soft leaves as well as some fruits and nuts and plant shoots.