Introducing
Your new presentation assistant.
Refine, enhance, and tailor your content, source relevant images, and edit visuals quicker than ever before.
Trending searches
A descendant of Pliohippus most likely gave rise to the Pleistocene genus Equus, which rapidly spread to Europe, Asia, Africa, and South America. However, by the end of the Pleistocene the genus was extinct in the New World. Nine species survive to this day in the Old World – the wild horse, donkeys, and zebras.
Merychippus lived 20.43—10.3 mya, they also had three toes, but the central toe bore most of the weight. The structure of the foot suggests that a strong elastic ligament, like that of modern horses, passed behind this central toe. Unlike Hyracotherium and Mesohippus, the teeth of this horse were high-crowned and had a more complex chewing surface.
The root of the family tree of the horse is to be found in a creature called Hyracotherium, which lived between 45 and 55 million years ago, during the Eocene period. It had 4 toes on each front foot, and 3 toes on each back foot. It had low-crowned teeth. Its characteristics are those of a forest-dwelling animal that ate foliage.
High crown teeth
Hooves
35mya
25mya
15mya
5mya
45-55mya
Equus ferus caballus (or the modern horse) emerged about 5 mya. E. ferus was lager yet. They also had modern day hooves, which gave them an advantage over their predecessors in running and in supporting their massive bodyweight. They have probably developed this trait in order to enhance their ability to expand across thousands of miles of land, which is why they have expanded so rapidly over the past million years.
The Merychippus line led to Pliohippus, who lived about 15 mya. A late Miocene to Pliocene form. In Pliohippus the side toes became vestigial – although some species are now known to have had three toes and the teeth were high-crowned. Larger than predecessors.
Next came the Mesohippus, which lived 32 to 37 million years ago. Mesohippus, a sheep-sized Oligocene form, had only three toes on the forefoot. As in Hyracotherium, the teeth were low-crowned. Mesohippus appears to have become extinct by the middle Oligocene, and is commonly thought to have given rise to the characteristic Miocene genus Merychippus.