Merychippus is an extinct proto-horse of the family Equidae that was endemic to North America during the Miocene, 15.97–5.33 million years ago. It had three toes on each foot and is the first horse kn

Hyracotherium is an extinct genus of small perissodactyl ungulates that was found in the London Clay formation. This small, fox-sized animal was once considered to be the earliest known member of Equi