Camarasaurus

CAMARASAURUS (CAM-er-uh-SORE-us)

Period: Late Jurassic

Order, Suborder, Family: Saurischia, Sauropodomorpha, Camarasauridae

Location: North America

Length: 60 feet (18 meters)

Camarasaurus was probably the most common sauropod dinosaur of the Late Jurassic Morrison Formation in North America. This large, 25-ton plant-eater was strong and massive, with powerful legs, a strong neck and tail, and a rounded head. Deep pockets or chambers in the vertebrae (bones of the spine) of Camarasaurus lightened the skeleton without giving up strength. It is also how the dinosaur got its name, which means "chambered reptile."

The most unusual features of Camarasaurus were on its head. The large jaw bones had strong jaw muscles, and the teeth were unusually large for a sauropod. They were as large as chisels, with sharp points that chopped the plants it ate. Camarasaurus probably fed on plants that were coarse and tough. Its relatives Apatosaurus and Diplodocus, with their small weak teeth, probably ate soft, tender plants.

With large eyes and nostrils, Camarasaurus was alert and active. Like other sauropods, it probably moved in herds. It lived in the arid and semi-arid open country of North America.

One Camarasaurus pelvis from the Cleveland-Lloyd Dinosaur Quarry in Utah has huge grooves in the bones where an Allosaurus tore into the flesh and gouged the bones. Allosaurus was its fiercest enemy, but an adult Camarasaurus was so much larger that it was seldom attacked. A complete skeleton of a juvenile Camarasaurus was excavated from Dinosaur National Monument in Utah. Such skeletons are rare. Perhaps young sauropods grew to adult size quickly, so there is little chance of finding them in the fossil record.

One interesting twist of fate for Camarasaurus was that its head was mistakenly placed on the skeleton of Apatosaurus at the Carnegie Museum of Natural History. The mistake was not fixed for 75 years.