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''Camarasaurus'' ( ) was a genus of quadrupedal, herbivorous dinosaurs. 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 Period (late Oxfordian to Tithonian stages), between 155 and 145 million years ago. The name means "chambered lizard", referring to the hollow chambers in its vertebrae (Greek ''καμαρα''/''kamara'' meaning "vaulted chamber", or anything with an arched cover, and ''σαυρος''/''sauros'' meaning "lizard"). == Description == ''Camarasaurus'' is among the most common and frequently well-preserved sauropod dinosaurs. The maximum size of the most common species, ''C. lentus'', was about 15 meters (50 ft) in length. The largest species, ''C. supremus'', reached a maximum length of 23 meters (75 ft) and maximum estimated weight of 47 tonnes (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 centimeter 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 sharpened claw. Like most sauropods, the front limbs were shorter than the hind legs, but the high position of the shoulders meant there was little slope in the back. Serving the purpose of weight-saving, as seen in other sauropods, many of the vertebrae were hollowed out or ''pneumatic'', riddled with passages and cavities for an intricate system of air sacs connected to the lungs. This feature was relatively unknown at the time ''Camarasaurus'' was discovered, and was the inspiration for its name, meaning "chambered lizard". The neck and counterbalancing tail were shorter than usual for a sauropod of this size. ''Camarasaurus'', again like certain other sauropods, had an enlargement of the spinal cord near the hips. Palaeontologists originally believed this to be a second brain, perhaps necessary to co-ordinate such a huge creature. However, while it would have been an area of large nervous, probably reflex (automatic) activity, it was not a brain, and such enlargements are actually found to some degree in all vertebrate animals. ''Camarasaurus lewisi'' and ''C. grandis'' both had more robust radii than fellow sauropod ''Venenosaurus''.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Camarasaurus」の詳細全文を読む スポンサード リンク
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