Photo: National Park Service, Fossil Butte National Monument
- Order
- Perissodactyla
- Family
- Equidae
- Size
- About 33 cm / 13 in at the shoulder (adult specimen)
Known from only two FBM specimens — including the most complete dawn-horse skeleton ever found.
Living species of the Order Perissodactyla include horses, tapirs, and rhinoceroses — mammals with an odd number of toes. The family Equidae has seven modern species including horses, donkeys, and zebras.
One P. venticolus specimen was found in nearshore deposits and the other in mid-lake. Scientists are unsure how this non-aquatic species ended up in the middle of Fossil Lake — it may have fled a predator into the lake, or been swept in from a river and drowned.
The mid-lake specimen measures 33 centimeters tall at the shoulder and is believed to be a full-grown adult. It has four small hoofed toes on its front limbs and three on its back limbs. Its long head, slim body, and long hind legs indicate this species was a strong jumper.
Species text: National Park Service, Fossil Butte National Monument — Fossil Mammal Species.