Definition

Noun: 1. An extinct three-toed horse of the Oligocene epoch: Mesohippus is the genus name for a prehistoric, three-toed horse that lived in North America approximately 30 to 40 million years ago during the Oligocene epoch. It represents an important evolutionary stage in the horse lineage, being larger and more horselike than its earlier ancestors but not a direct ancestor of modern one-toed horses.

Usage Examples

• Noun:
  • Fossils of Mesohippus show it had three toes on each foot, though it primarily walked on its central toe.
  • The discovery of a Mesohippus skeleton helped paleontologists understand the migration of early horses.
  • Mesohippus was significantly larger than its predecessor, Hyracotherium.

Advanced Usage

• In evolutionary biology: The term is used to denote a specific transitional form in the fossil record.
  • The limb structure of Mesohippus provides clear evidence for the adaptation to running on harder, drier grasslands.

Variants and Related Words

• Mesohippine (adj): Pertaining to or characteristic of the genus .
  • The mesohippine fossils were found in the Badlands.

Synonyms

• Three-toed horse (descriptive term)
• Transitional horse (in an evolutionary context)

Related Terms (Scientific Context)

• Merychippus: A later, more advanced three-toed horse genus.
• Hyracotherium: An earlier, smaller ancestor, often called "eohippus".
• Equus: The modern genus of horses, to which is indirectly related.

Noun

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