Camarasaurus (//KAM-ər-ə-SAWR-əs) was a genus of quadrupedal, herbivorousdinosaurs. It was the most common of the giant sauropods to be found in North America. Its fossil remains have been found in the Morrison Formation of Colorado and Utah, dating to the Late Jurassic epoch (Kimmeridgian to Tithonian stages), between 155 and 145 million years ago.
Camarasaurus presented a distinctive cranial profile of a blunt snout and an arched skull that was remarkably square. It likely travelled in herds, or at least in family groups.
The name means “chambered lizard”, referring to the hollow chambers in its vertebrae (Greekκαμαρα (kamara) meaning “vaulted chamber”, or anything with an arched cover, and σαυρος (sauros) meaning “lizard”.
Camarasaurus is among the most common and frequently well-preserved sauropod dinosaurs uncovered. The maximum size of the most common species, C. lentus, was about 15 m (49 ft) in length. The largest species, C. supremus, reached a maximum length of 23 m (75 ft) and, a maximum estimated weight of 47 metric tons (51.8 tons).
The arched skull of Camarasaurus was remarkably square and the blunt snout had many fenestrae, though it was sturdy and is frequently recovered in good condition by paleontologists. The 19-cm-long (7.5-in) teeth were shaped like chisels (spatulate) and arranged evenly along the jaw. The strength of the teeth indicates that Camarasaurus probably ate coarser plant material than the slender-toothed diplodocids.
Each front limb bore five toes, with the inner toe having a large, sharp claw. Like most sauropods, the front limbs were shorter than the hind legs, but the high position of the shoulders meant little slope in the back existed.
Serving the purpose of weight-saving, as seen in other sauropods, many of the vertebrae were hollowed out, or “pneumatic”; that is, the vertebrae were riddled with passages and cavities for an intricate system of air sacs connected to the lungs. This feature was little understood at the time Camarasaurus was discovered, but its structure was the inspiration for the creature’s name, meaning “chambered lizard”. The neck and counterbalancing tail were shorter than usual for a sauropod of this size. Camarasaurus, like certain other sauropods, had an enlargement of the spinal cord near the hips. Paleontologists[who?] originally believed this to be a second brain, perhaps necessary to co-ordinate such a huge creature. Indeed, while it would have been an area of intensive nervous system—probably reflex, or automatic—activity, it was not, however, a brain; such enlargements are frequently found to some degree in vertebrate animals.
Camarasaurusgrandis had a more robust radius than fellow sauropod Venenosaurus.
A specimen of Camarasaurus called SMA 0002 (which has also been assigned to Cathetosaurus) from Wyoming’s Howe-Stephens Quarry, referred to as “E.T.”, shows evidence of soft tissue. Along the jaw line, ossified remains of what appear to have been the animal’s gums have been recovered, indicating that it had deep-set teeth covered by gums, with only the tips of the crowns protruding. The teeth were, upon death, pushed further out from their sockets as the gums retracted, dried, and tightened through decay. The examinations of the specimen also indicate that the teeth were covered by tough outer scales and possibly a beak of some variety, though this is not known for certain.