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Fossil range: late Eocene to early Miocene
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Family: Equidae
Genus: Miohippus
Marsh, 1874

Miohippus was a genus of prehistoric horse that lived in what is now North America during the Oligocene Period some 25 to 40 million years ago. It is believed to have branched off from Mesohippus, and the two coexisted for about four-eight million years.

Additional recommended knowledge

Mesohippus had died out by the mid-Oligocene, and Miohippus became much larger than it. They weighed around 40 to 55 kilograms. They were somewhat larger than most earlier Eocene horse ancestors, but still much smaller than modern horses, which typically weigh about 500 kilograms.

Miohippus was larger than Mesohippus and had a slightly longer skull. Its facial fossa was deeper and more expanded, and the ankle joint was subtly different. Miohippus also had a variable extra crest on its upper molars, which gave it a larger surface area for chewing tougher forage. This would become a typical characteristic of the teeth of later equine species.

Miohippus had two forms, one of which adjusted to the life in forests, while the other remained suited to life on prairies. The forest form led to the birth of Kalobatippus (or Miohippus intermedius), whose second and fourth finger again elongated for travel on the softer primeval forest grounds. The Kalobatippus managed to relocate to Asia via the Bering Strait land bridge, and from there moved into Europe, where its fossils were formerly described under the name Anchitherium. Kalobatippus is then believed to have evolved into a form known as Hyohippus, which became extinct near the beginning of the Pliocene.

See also

  • Evolution of the horse


  1. ^ McKenna, M. C, and S. K. Bell (1997). Classification of Mammals Above the Species Level. Columbia University Press. ISBN 023111012X. 
  • Evolution of the Horse
  • Horse Evolution, by Kathleen Hunt
  • Evolution of Horses
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Miohippus". A list of authors is available in Wikipedia.
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