Its fossil remains have been found in the Morrison Formation, 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, typical of basal Macronarians.

Camarasaurus was named in 1877 by Edward Drinker Cope, during the period of scientific rivalry between him and Othniel Charles Marsh known as the Bone Wars.

The first record of Camarasaurus comes from the spring of 1877 when Mr. Oramel William Lucas of Cañon City, Colorado discovered some large vertebrae at Garden Park, which he sent to Edward Drinker Cope who was based in Philadelphia, Pennsylvania.

[2] After receiving the original bones, Cope employed collectors who gathered more of the material which was described in 1921 by Henry Osborn and Charles Mook.

[2] In 1877 a reconstruction of the skeleton of Camarasaurus was painted by Dr. John Ryder on several canvasses, under the direction of Professor Cope who would use them in lectures to impress his audience.

[2] The next Camarasaurus discovery came later in 1877, when a fragmentary posterior skull and a partial postcranial skeleton was discovered and collected in Quarry 1, Como Bluff, Wyoming by crews working for Othniel Charles Marsh.

In 1998, Kenneth Carpenter argued that the stratigraphic position of the find suggested it was more likely to be synonymous with C. grandis,[6] but in a 2005 study of the biostratigraphic distribution of Camarasaurus, Takehito Ikejiri retained it in synonymy with C.

[18] In 2013, Octavio Mateus and Emanuel Tschopp argued that C. lewisi was actually its own genus based on a specimen found at Howe Quarry in 1992[21] that they referred to the species.

[30] The northernmost specimen of Camarasaurus was discovered in 2005 in the Snowy Mountains region of central Montana and consists of a nearly complete skull and several postcranial elements.

[32] It is found in a wide area over the western United States, from as far north as Montana to as far south as New Mexico, in rocks of the Morrison Formation.

[21][13][2] Similar to other Macronarians, it had the typical large naris, long forelimbs, and short tail compared to the contemporary Diplodocids.

[citation needed] 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.

[41] As in other sauropods, the vertebrae of the neck and torso contained chambers that in life were filled by air sacs connected to the respiratory system.

[40][43] Camarasaurus is the type genus of the family Camarasauridae, members of which are medium-sized Macronarian sauropods that mostly date to the Late Jurassic.

[44][2] When Edward Cope described Camarasaurus in 1877, he believed it was a dinosaur closely related to Cetiosaurus, Bothriospondylus, Ornithopsis, Anchisaurus (Megadactylus), and Pneumatosteus,[1] but didn’t name a group for these taxa until the description of Amphicoelias when he erected Camarasauridae.

[45][46] A simplified cladogram of basal Macronaria after Tan et al (2020) is shown below: Turiasauria Jobaria Diplodocoidea Camarasaurus Bellusaurus Europasaurus Tehuelchesaurus Galvesaurus Euhelopus Titanosauriformes 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.

[7][50] C. supremus, as its name suggests, is the largest known species of Camarasaurus[2] and one of the most massive sauropods known from the late Jurassic Morrison Formation.

Stratigraphic evidence suggests that chronological sequence aligned with the physical differences between the three species, and it describes an evolutionary progression within the Morrison Formation.

This immediate succession of species, as well as the very close similarity between the two, suggests that C. supremus may have evolved directly from C. lentus, representing a larger, later-surviving population of animals.

[51]Previously, scientists have suggested that Camarasaurus and other sauropods may have swallowed gastroliths (stones) to help grind the food in the stomach, regurgitating or passing them when they became too smooth.

[66] Eagle et al. performed clumped isotope thermometry on the enamel covering the teeth of various Jurassic sauropods, including Camarasaurus.

[68] A Camarasaurus pelvis recovered from Dinosaur National Monument in Utah shows gouging attributed to Allosaurus[69] and on the ilium of the C. lewisi holotype there are large Theropod bite marks.

[20] In 1992, a partial C. grandis skeleton was discovered at the Bryan Small Stegosaurus Quarry of the Morrison Formation near Canon City, Colorado.

[72] Other candidates identified by the scientists for the origin of the spur-bearing lesion included: The Morrison Formation, situated along the eastern flank of the Rocky Mountains, is home to a fossil-rich stretch of Late Jurassic rock.

Dinosaur and trace fossils are found particularly in the Morrison Basin, which stretches from New Mexico to Alberta and Saskatchewan and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west.

The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs such as Maraapunisaurus, Amphicoelias, Barosaurus, Diplodocus, Apatosaurus, Brontosaurus, and Brachiosaurus.

Dinosaurs living alongside Camarasaurus included the herbivorous ornithischians Camptosaurus, Gargoyleosaurus, Dryosaurus, Stegosaurus, and Nanosaurus.

[89] Other organisms in this region included bivalves, snails, ray-finned fishes, frogs, salamanders, turtles, sphenodonts, lizards, terrestrial and aquatic crocodylomorphs, and several species of pterosaurs such as Harpactognathus and Mesadactylus.

The flora of the period has been revealed by fossils of green algae, fungi, mosses, horsetails, cycads, ginkgoes, and several families of conifers.