Period: Late Jurassic period (155 – 145 million years ago)
Group: Sauropods (lizard feet)
Size: It was 27 m long and 5 m tall at the hips. It weighed between 10,000kg – 20,000kg
Characteristics: The Diplodocus walked slowly on four elephant-like legs and had an 8 m long neck and a 14 m long, whip-like tail. Its front legs were shorter than its back legs and they had four toes and a thumb claw on each foot. Palaeontologists believe the Diplodocus could not hold their necks more than 5.4 m off the ground. Its head was only half a meter long and its nostrils were at the top, giving it a good sense of smell. The Diplodocus had blunt teeth set at the front of their jaws that were used for stripping leaves off branches. Its main food was probably conifers but may also have included ferns and moss.
Named by: Othniel Charles Marsh in 1878
Discovery: The first Diplodocus fossil was found by Earl Douglass and Samuel W. Williston in 1877. Many more Diplodocus fossils, including a skin impression, have been found in the Rocky Mountains of the western North America, in particular Colorado, Montana, Utah, and Wyoming.