from the GNU version of the Collaborative International Dictionary of English

  • n. An extinct mammal of the Horse family, but not larger than a sheep, and having three toes on each foot.

from The Century Dictionary and Cyclopedia

  • n. A genus of very small three-toed horses, of the family Equidæ founded by Marsh in 1875 upon remains from the early Miocene of North America.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. North American three-toed Oligocene animal; probably not directly ancestral to modern horses


Sorry, no etymologies found.


  • This mesohippus, c. 40mya apparently looks like a modern horse to Bob.

    Church Signs on CNN iReport - The Panda's Thumb

  • By about 30 mya, the mesohippus, a collie-dog-Sized, horselike animal, became typical of the medium-sized mammals appearing in the record.

    The Source

  • And then, about thirty million years ago, when the land that was to form the twin pillars was being laid down, mesohippus developed, twenty-four inches high at the shoulders and with all the basic characteristics of his ancestors, except that he had only three toes on each of his feet.


  • A group of new scholars is pushing the line that the ancestors of our horse developed in America only as far as mesohippus, which then emigrated to Asia, where it developed into the horse proper, in the form of the Appaloosa, which thus becomes the great ancestor of subsequent breeds.


  • But what gained greatest attention, especially from ranchers in the west, was his discovery in subsequent years of handsome skeletons of four of the progenitors of the horse: eohippus, mesohippus, miohippus and the crucial, determinative merychippus.



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