Mesohippus

Mesohippus
Mesohippus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Perissodactyla
Family:	Equidae
Genus:	Mesohippus Marsh, 1875
Species
M. bairdi M. barbouri M. braquistylus M. equiceps M. hypostylus M. intermedius M. latidens M. longiceps M. metulophus M. montanensis M. obliquidens M. proteulophus M. westoni

Left: General outline. Center: forelimb bones. Right: a molar tooth (white: cement; dotted: dentine; dark: enamel)

Mesohippus Greek (meso meaning "middle" and hippus meaning "horse") lived some 32 million years ago in the mid- Oligocene. It had longer legs than its predecessor Hyracotherium and stood about two feet tall. It had also lost a toe and now stood predominantly on its middle toe, although the other two were also used. The face of Mesohippus was longer and larger than earlier equids. It had a slight facial fossa, or depression in the skull. The eyes were rounder and were set wider apart and farther back. Like many fossil horses, Mesohippus was common in North America.

Its teeth were also larger and contained a single gap behind the front teeth, where the bit now rests in the modern horse. In addition, it had another grinding tooth, making a total of six. Like Hyracotherium, Mesohippus was a browser that fed on tender twigs and fruit. The cerebral hemisphere, or cranial cavity, was notably larger than that of its predecessors; its brain was like that of today's horse.

Mesohippus was extinct by the mid-Oligocene period.

See also

• Evolution of the horse

External links

• Mikko's Phylogeny Archive Equidae - horses
• Mesohippus at the Berkeley Natural History Museums