The Camarasaurus (pronounced KAM-a-ra-SORE-us) was a genus of quadrupedal, herbivorous dinosaurs found in Royal Tyrrell Museum. They are the most normal of the giant sauropods to be establish in North America, but only average in size, about 18 meters (60 feet) in length as adults, and weighing up to 28 tonnes (31 tons). It lived in the late Jurassic period, between 155 and 145 million years ago.
The main feature of attention is its skull. The skull was remarkably square and the blunt snout had many holes, though it was sturdy and often recovered in good condition.
The 19 cm-long (7.5 inch) teeth were shaped like chisels (spatulate) and set consistently along the jaw. The power of the teeth indicates that Camarasaurus almost certainly ate coarser plant material than the fragile-toothed diplodocids.
Like a chicken, it would almost certainly have swallowed stones (gastroliths) to help physically digest the food in the stomach, and then regurgitated or passed them when they became too smooth. Consistent with this suggestion, the rock formation in which they are often found (the Morrison Formation) includes a large number of isolated piles of strangely smooth stones.
Each giant foot bore five toes, with the internal toe having a large sharpened claw for self-defense. Like most sauropods, the front legs were shorter than the hind legs, but the high position of the shoulders destined there was little slope in the back. In some sauropods there were long upward projections on each vertebra, but the nonattendance of such structures from the spine of Camarasaurus suggests that it was not able to raise itself up on its hind legs.
The vertebrae were nevertheless specialized; as a weight-saving device seen in many later sauropods, the vertebrae were hollowed out, hence the name "chambered lizard". Like a new elephant, Camarasaurus appears to have a wedge of spongy tissue at the base of the heel, to support the weight of such a large creature. The neck, and counter-balancing tail, was shorter than usual for a sauropod of this size.
Camarasaurus, again like certain other sauropods, had an amplification of the spinal cord near the hips. Paleontologists originally believed this to be a second brain, perhaps essential to co-ordinate such a huge creature. Modern opinion asserts that while it was an area of large anxious activity, it was not a brain. However, this enlargement was actually larger than the extraordinarily small brain contained in the animals' box-like skull.
It is optional by some paleontologists that Camarasaurus may have lived for up to a hundred years.
There is a fossil evidence of adults and young that died together. This suggests that Camarasaurus traveled in herds. Also, recovered camarasaur eggs are establish in lines, not in neatly approved nests as with some other dinosaurs. Like most sauropods, it seems Camarasaurus did not care for its young.
The first record of Camarasaurus ("chambered lizard") comes from 1877, when a few scattered vertebrae where situated in Colorado by Oramel W. Lucas. The paleontologist Edward Drinker Cope paid for the bones as element of his long-running and acrimonious competition with Othniel Charles Marsh (known as the Bone Wars), and named them in the same year.
It was not until 1925 that a whole skeleton of Camarasaurus was recovered, by Charles W. Gilmore. However, it was the skeleton from a young Camarasaurus so many illustrations of the dinosaur from the time show it to be much lesser than it is now known to be.
The Morrison Formation along the eastern flank of the Rocky Mountains is home to a rich widen of late Jurassic rock. A large number of dinosaur species can be establish here, including relatives of the Camarasaurus such as Diplodocus, Apatosaurus and Brachiosaurus. However camarasaurs are the most plentiful of all the dinosaurs in the Formation, and there have been a number of complete skeletons improved from Colorado, New Mexico, Utah, and Wyoming.
The scientific arrangement of the Camarasaurus using the Linnaean system is given in the box to the upper right, but amongst paleontologists this method of categorizing dinosaurs has been mainly supplanted by cladistics. A simplified version of one probable branching evolutionary tree (cladogram), showing the relationship between Camarasaurus and the other major groups of sauropods follows:
Saurischia ("lizard hipped" dinosaurs)
Sauropoda ("lizard feet")
Macronaria ("large nostrils") motha fucka
Brachiosauridae (like the Brachiosaurus and Sauroposeidon)
Titanosauridae (like the Argentinosaurus)
Diplodocidomorpha (like the Apatosaurus and Diplodocus)
Camarasaurus is considered to be a basal macronarian, or more personally related to the common ancestor of all macronarians than more evolved forms like Brachiosaurus.
Cope's unique Camarasaurus was the species C. supremus ("the biggest chambered lizard") in 1877. Other species since discovered include C. grandis ("grand chambered lizard") later in 1877, C. lentus in 1889, and C. lewisi (originally Cathetosaurus) in 1988.