Camarasaurus (ca·mar·a·saur·us) was probably the most common sauropod dinosaurs to be found in North America but only average in size: about 18 meters (60 ft) in length as adults, and weighing up to 18 tonnes (19.8 tons). It lived in the Late Jurassic Morrison Formation (late Oxfordian to Tithonian stages), between 155 and 145 million years ago. A Camarasaurus pelvis recovered from Dinosaur National Monument in Utah shows gouging attributed to Allosaurus.[1]
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 skeleton without giving up strength. It is also how the dinosaur got its name, which means "chambered reptile."
Anatomy[]
Camarasaurus lentus skull
The arched skull of Camarasaurus may have contributed to the name 'chambered lizard'. The skull 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. Like a chicken, it may have swallowed stones (gastroliths) to help grind the food in the stomach and then regurgitated or passed them when they became too smooth.
Sketches of Camarasaurus head movements by Erwin Christman
Each giant foot bore five toes, with the inner 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 meant there was little slope in the back. In some sauropods, there were long upward projections on each vertebra but the absence of such structures from the spine of Camarasaurus suggests that it was not able to raise itself on its hind legs.
The vertebrae were nevertheless specialized. Serving the purpose of weight-saving, as seen in many later sauropods, some of the vertebrae were hollowed out. This feature may have contributed to the name "chambered lizard". Like a modern elephant, Camarasaurus appears to have had 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 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. Modern opinion asserts that, while it would have been an area of large nervous, possibly reflex, (automatic) activity, it was not a brain. However, this enlargement was actually larger than the remarkably small brain contained in the animals' box-like skull.
Discovery[]
E.S. Christman's pen-drawing of a Camarasaurus skeleton, 1921
The first record of Camarasaurus comes from 1877, when a few scattered vertebrae were located in Colorado, by Oramel W. Lucas. The paleontologist Edward Drinker Cope paid for the bones, as part of his long-running and acrimonious competition with Othniel Charles Marsh (known as the Bone Wars) and named them in the same year. Marsh later named some of his sauropod findings Morosaurus grandis but most paleontologists today consider this to be a species of Camarasaurus [1]. Such naming conflicts were common between the two rival dinosaur hunters, the most famous being Brontosaurus/Apatosaurus.
1925 illustration of the first full skeleton of Camarasaurus.
It was not until 1925 that a complete skeleton of Camarasaurus was recovered, by Charles W. Gilmore. However, it was the skeleton from a young Camarasaurus, which is why so many illustrations of the dinosaur from the time show it to be much smaller than it is now known to be. The specimen was immature, leading to many illustrations at the time portraying the dinosaur as much smaller than it actually was.
The earliest known skeletal reconstruction of a sauropod dinosaur: C. supremus by John A. Ryder, 1877
The Morrison Formation, along the eastern flank of the Rocky Mountains, is home to a rich stretch of Late Jurassic rock. A large number of dinosaur species can be found here, including relatives of the Camarasaurus such as Diplodocus, Apatosaurus and Brachiosaurus. However, camarasaurs are the most abundant of all the dinosaurs in the Formation.[2] There have been a number of complete skeletons recovered from Colorado, New Mexico, Utah, and Wyoming.
A recent discovery was made in Old Snowmass, Colorado.
Description[]
Scale diagram of three known species of Camarasaurus
Restoration of a C. supremus herd
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 flees and gouged the bones. Allosaurus was its fiercest enemy, but and 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.
Camarasaurus lived in the Morrison Formation, Colorado and Utah. Camarasaurus had hollow chambers in its vertebrae to lighten the load on its sturdy legs. Camarasaurus browsed in the high treetops of the Late Jurassic. Camarasaurus was about 23 meters long, 10 meters high and weighed about 20,000 kilograms. Camarasaurus are among the most frequently well-fossilized and common sauropods ever discovered. The most common species is C. lentus, and the largest species is C. supremus. The skull of Camarasaurus is arched, and very squared. It is known for a blunt rostrum and many large fenestrae. Many sturdy and intact skulls are documented. Teeth are about 19 centimeters (7.5 inches), and are spatulate in tightly-packed even rows arranged around the jaws. Teeth of Camarasaurus are remarkably strong, indicating individuals likely ate coarser foods, unlike the more slender-toothed diplodocids. Each forelimb adorns five toes; the innermost having a large sharp claw. The forelegs were smaller than the back, but the highly-arranged hips indicate a minor slope along the animals back.
As seen in other sauropods, Camarasaurus had pneumatic vertebrae that reduced the creatures' weight. When first discovered, little was known about what function they held, but they inspired the name "chambered lizard". The neck and tail were proportionally smaller compared to similarly-sized sauropods. It had an enlarged spinal cord by the hips, which some interpreted as evidence for a second brain, as they though such a large creature could not function with one small brain. The area was likely a reflex or automatic activity hotspot, but there is no such evidence of a brain, since some vertebrates have similar features. C. grandis, compared to Venenosaurus, has a more robust radius. In the past, the specimen SMA 0002 'E.T.' (sometimes as Cathetosaurus), originating from Howe-Stephens Quarry in Wyoming, shows trace of soft tissue, The ossified remains of what may be gums near the jawline were recovered, showing that Camarasaurus had deep-set teeth covered up-to-the-crown with gum tissue. As the remains decay, the teeth fall out of their sockets, and tightened as the tissue decayed. Marks on the teeth show they were covered by something, either tough scales or some sort of beak. This theory is not certain.
Some specimens of Camarasaurus have a skull <50% of the femoral length, which is a supposed synapomorphy of sauropoda, but other specimens have a skull >50& of the femoral length. This results in a morph with a large head that have been nicknamed "bobbleheads". This large-headed morph is seen in all species, across maturities and across the geographic an stratigraphic range. This has been hypothesized to be extreme individual variation or even sexual dimorphism.
Behaviour[]
Mounted Camarasaurus skeleton cast, Jurassic Museum of Asturias.
There is a fossil record of two adults and a 12.2 meter (40 ft) long juvenile that died together in the Late Jurassic Period, approximately 150 million years ago (in north east Wyoming, USA, excavated by the Division of Vertebrate Paleontology of the University of Kansas Natural History Museum and Biodiversity Center, during the 1997 and 1998 'field seasons'). It is assumed that their bodies were washed to their final resting place, in alluvial mud, by a river in spate. This suggests that Camarasaurus traveled in herds or, at least, 'family' groups. Also, recovered camarasaur eggs have been found in lines, rather than in neatly arranged nests as with some other dinosaurs, which appears to suggest that, like most sauropods, Camarasaurus did not tend its young.
Classification[]
The scientific classification of Camarasaurus, using the Linnaean system, is given in the box to the upper right but, among palaeontologists, this method of taxonomic classification of dinosaurs is being supplanted by the cladistics inspired phylogenetic taxonomy. A simplified version of one possible branching evolutionary tree, showing the relationship between Camarasaurus and the other major groups of sauropods, follows:
Saurischia ("lizard hipped" dinosaurs) `--Sauropoda ("lizard feet") |--Macronaria ("large nostrils") | |--Camarasauridae | `--Titanosauriformes | |--Brachiosauridae (which includes Brachiosaurus and Sauroposeidon) | `--Titanosauria (dinosaurs such as Argentinosaurus) `--Diplodocoidea (which includes Apatosaurus and Diplodocus)
Camarasaurus is considered to be a basal macronarian, more closely related to the common ancestor of all macronarians than to more derived forms like Brachiosaurus.
Camarasaurus supremus vertebrae at Quarry 1 in Garden Park c. 1878
Multiview skeletal reconstruction of C. supremus.
C. supremus, "the biggest chambered lizard", was named as the type species of Camarasaurus by Cope in 1877. C. grandis, "giant chambered lizard", was named in 1877, C. lentus in 1889 and C. lewesi (originally as Cathetosaurus) in 1988. C. supremus is the largest species of Camarasaurus and one of the largest Morrison sauropods. However, the animal was found indistinguishable from C. lentus apart from size. Atypical of Camarasaurus, remains are known from the Latest Uppermost Morrison. C. grandis and C. lentus were smaller and lived earlier. From stratigraphic evidence, an evolutionary progression may be visible due to chronological sequence and morphological difference. C. grandis appears in the oldest and lowest rock layers. C. lentus appears later, coexisting with C. grandis for several million years. They likely coexisted because of different niche occupation, due to differences in the spinal anatomy. Later, C. grandis disappears, leaving C. lentus. The latter disappears at the moment C. supremus is first recorded. The succession and close anatomy between C. lentus and C. supremus suggests C. supremus is a larger and late-surviving population of C. lentus. C. lewisi was named as Cathetosaurus lewisi, and was synonymized with Camarasaurus. In 2013, both genera split.
Paleobiology[]
C. lentus skull
There is a fossil record of two adults and a 12.2 meter long juvenile that died together in the Late Jurassic Period, (excavated in north east Wyoming, USA, by the Division of Vertebrate Paleontology of the University of Kansas Natural History Museum and Biodiversity Center, during the 1997 and 1998 'field seasons'). It is assumed that their bodies were washed to their final resting place, in alluvial mud, by a river in spate. This suggests that Camarasaurus traveled in herds or, at least, 'family' groups. Also, recovered Camarasaurus eggs have been found in lines, rather than in neatly arranged nests as with some other dinosaurs, which appears to suggest that, like most sauropods, Camarasaurus did not end its young. As for its digestion, some scientists had suggested that Camarasaurus and other sauropods may have swallowed stones to help grind the food in the stomach and then regurgitated or passed them when they became too smooth. However, more recent analysis of the evidence for stomach stones has suggested that this was not the case. Furthermore, the strong, robust teeth of Camarasaurus in particular were more developed than those of most sauropods, indicating that it may have processed food in its mouth to some degree before swallowing.
Herding[]
Around 150 million years ago in Wyoming, two 12.2 meter (40 foot) long juvenile Camarasaurus died together. This was suggested to have been washed together in a flood, or that Camarasaurus lived in herds or family groups. Other sites preserve their eggs in lines rather than mounds, which may insinuate these animals did not care for their young.
Feeding[]
It was previously assumed these dinosaurs ate gastroliths to help grind food, which would become smooth. However, research shows Camarasaurus had more robust, developed teeth, with D'Emic et al. finding they replaced teeth every 62 days, indicating it masticated food in it's mouth before swallowing. Others find Camarasaurus preferred different vegetation, allowing sauropods to share an ecosystem without competing.
Growth[]
Griebeler et al. in 2013 determine the long-bone histology of C. sp. CM 36664, found a weight of 14,247 kilograms (15.7 short tons), a sexual maturity of 20 years and a death age of 26 years.
Metabolism[]
In the teeth of various Jurassic sauropods, Eagle et al. performs clumped isotope thermometry in the enamel. The temperature obtained was 32.4-36.9 °Celsius (90.3-98.4 °Fahrenheit). This is comparable to modern mammals.
Paleopathology[]
C. lentus in the death pose.
A pelvis recovered from Dinosaur National Monument, Utah has gouging marks from an Allosaurus. In 1992, a C. grandis specimen from Bryan Small Stegosaurus Quarry near Canon City, Colorado was discovered, among the remains were a partial right humerus (DMNH 2908) and vertebrae from the back and tail. Pathologies in the humerus were described in 200 by Lorie McWhinney, Kenneth Carpenter and Bruce Rothschild. A juxtacortical lesion 25x18 centimeters that resembles woven fibers was noted, appearing as a sign of injury/illness. The "undulating fibrous bundles" oriented by the m. brachialis, with the lesion's lack of porosity near the ends indicating the periostitis was either inactive, or healed. McWhinney and others argue the pathology would have been extremely difficult for the animal, exerting pressure on the muscles, compressing the blood vessels and nerves. This would have reduced the range of motion in the forelimb's flexor and extensor muscles. This would have hindered the mM. brachialis, m. brachoradialis and the m. biceps brachii (to a lesser degree) to the the lesion's position. It was found the muscle and periosteum inflammation would have complicated the lower forelimb. Such a lesion would have caused long-term fasciitis and myositis. All of these combined would have caused moderate-severe effects on the limb's movement, making activities such as foraging and escaping predators harder than normal. McWhinney et al. performed a CT scan in 3-millimeter increments, finding the mass has a consistent radiodensity, separating from the bone's cortex via a radioleucent line. No evidence of a stress fracture or infections like osteomyelitis or periostitis were found. Osteochondroma was ruled out due to the spur having an axis of 25°, relative to the humerus' vertical axis, where osteochondroma would form a 90° angle. Others identify the source as:
- Hypertrophic osteoarthropathy, ruled out because of the spur-like formation.
- Osteoid osteoma, which would not explain the spur or osteoblastic reactions.
- Shin splints and tibial stress syndrome, being a possible origin that has similar symptoms, the former not explaining the spur.
- Myositis ossificans traumatica (circumscripta) was deemed possible but unlikely.
- Avulsion injury, introduced by McWhinney and others, this injury is caused by repetitive overexertion in the muscles, which was deemed the most likely cause. It is thought it originated in the m. brachialis, forming an elliptical mass sloping downward. The spur was caused based on the osteoblastic response of the base of the m. brachioradialis, caused by flexor motion.
Paleoecology[]
A Camarasaurus skull from Dinosaur National Monument in mudstone matrix.
The Morrison sat along the edge of the eastern end of the Rocky Mountains. A large amount of dinosaurs are known from this formation, including fellow sauropods Diplodocus, Apatosaurus and Brachiosaurus, with Camarasaurus being the most common dinosaur in the formation. Specimens from Colorado, New Mexico, Utah and Wyoming are often found in stratigraphic zones 2-6. The Morrison Formation is 156.3 million years old at the base and 146.8 million years old at the top. This places it as ranging from the Oxfordian-Kimmeridgiann in the Early Tithonian of the Late Jurassic. The formation was semiarid, with wet and dry seasons that are distinct. The Morrison Basin, stretching from New Mexico to Alberta and Saskatchewan, being formed when the precursor of the Front Range in the Rocky Mountains pushed upwards to the west, preserves dinosaur and trace fossils. The formation was formed when material eroded off an east-facing drainage basin, carried by streams and rivers and depositing into swampy lowlands, lakes, river channels and floodplains. This is similar to the Solnhofen Limestone and Tendaguru Formations. The Morrison was the center of the Bone Wars, starting in 1877.
The Morrison was dominated by Barosaurus, Diplodocus, Apatosaurus, Brontosaurus and Brachiosaurus. Other herbivores include Camptosaurus, Gargoyleosaurus, Dryosaurus, Stegosaurus and Othnielosaurus. Predators include Saurophaganax, Torvosaurus, Ceratosaurus, Marshosaurus, Stokesosaurus, Ornitholestes and Allosaurus. The latter listed make up 75% of all Morrison theropods. Camarasaurus is often found alongside Allosaurus, Apatosaurus, Stegosaurus and Diplodocus. The region also contains bivalves, snails, ray-finned fish, frogs, salamanders, turtles, spheonodonts, lizards, both terrestrial and aquatic crocodylomorphs, docodonts like Docodon, multituberculates, symmetrodonts, triconodonts and pterosaurs such as Harpactognathus and Mesadactylus. Flora includes green algae, fungi, moss, horsetails, cycads, ginkgoes, several conifer families, tree ferns, ferns (the latter two in river-lining forests) and fern savannas with the occasional Brachyphyllum tree.
JPInstitute.com Description[]
Camarasaurus was a very heavily built member of the long-necked sauropod family of Jurassic dinosaurs. It is very well known by scientists and recently a family of these large creatures was discovered in the Western U.S. Camarasaurus is also a part of one of paleontology's big mistakes when its head was put on the body of Apatosaurus and called Brontosaurus.
Compared to some of the other sauropods, Camarasaurus had a relatively short neck and tail. It also had a large head compared to other sauropods, but the head was almost hollow. The skull openings for the nose and eyes were very large. This is the most common North American sauropod found, with more than ten fairly complete skeletons unearthed to date. At least four species have been identified within this genus.
Camarasaurus gets its name from the hollow spaces in its neck vertebrae. These would have made the neck lighter and easier for the dinosaur to lift and move about. This dinosaur also had the largest teeth among sauropods.
Dinosaur Field Guide Description[]
Camarasaurus. ("chambered lizard") is one of the most bulky of the sauropods, the big long-necked plant-eaters, It has teeth that are shaped like spoons, only much thicker. The head is large and boxlike, with powerful jaws and a wide bite. Camarasaurus fed on very tough, fibrous plants and, like all sauropods, did not chew food but swallowed it whole. This is why sauropods swallowed gastroliths, or stomach stones. The stones helped to grind up the plants inside their stomachs. The name Camarasaurus comes from the chambers that can be seen in its vertebrae. These hollow chambers serve to lighten the skeleton and give it strength. Some scientists believe that these chambers also housed an air-sac system similar to that in birds. Air sacs are part of the respiratory system and are connected to the lungs. This would have greatly helped the air flow through the lungs. Gigantic animals like sauropods would have benefited from a more efficient system of breathing, because carrying around over twenty-five tons of weight would require a lot of oxygen.
Fun Facts[]
Camarasaurus is one of the very few dinosaurs for which juvenile skeletons have been found along with adults.
Trivia[]
This dinosaur was part of the famous "Bone Warg" of the 1870s between Edward Drinker Cope and Othniel C. Marsh, two scientists who comlpeted to name the most dinosaurs.
Gallery[]
Appearance in other media[]
Jurassic Park[]
- Camarasaurus appeared in the video game Jurassic Park: Operation Genesis.
- Camarasaurus appeared in the video game Jurassic Park Builder.
- Camarasaurus appeared in the video game Jurassic World: Evolution.
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Read more Camarasaurus on Jurassic Park Wiki |
Links[]
References[]
- https://en.wikipedia.org/wiki/Camarasaurus
- https://twitter.com/DoubleBeam/status/1475164192101470212
- https://twitter.com/Bhmllr/status/1477830363019894784/photo/3
Template:Reflist
- ↑ "Camarasaurus." In: Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B. The Age of Dinosaurs. Publications International, LTD. p. 56. ISBN 0-7853-0443-6.
- ↑ Template:Cite book