Camarasaurus ( ) was a genus of quadrupedal, herbivorous dinosaurs and is the most common North American sauropod fossil. 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. The name means "chambered lizard", referring to the hollow chambers, known as pleurocoels, in its cervical vertebrae (Greek () meaning "vaulted chamber", or anything with an arched cover, and () meaning "lizard". Camarasaurus contains four species that are commonly recognized as valid: Camarasaurus grandis, Camarasaurus lentus, Camarasaurus lewisi, and Camarasaurus supremus. C. supremus, the type species, is the largest and geologically youngest of the four. Camarasaurus is the type genus of Camarasauridae, which also includes its European close relative Lourinhasaurus. Camarasaurus was named in 1877 by Edward Drinker Cope, during the period of scientific rivalry between him and Othniel Marsh known as the Bone Wars. Soon after, Marsh named a genus Morosaurus, but it was subsequently shown to be synonymous with Camarasaurus. History Initial discovery 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. The original material sent consisted of a partial cervical vertebra, which would become the taxon's namesake, three dorsal vertebrae, and four caudal vertebrae. This specimen is now thought to have been composed of several individuals. From these initial fragmentary remains, Cope made his original description of Camarasaurus supremus (“supreme chambered lizard”) and founded the genus; these remains are now in the American Museum of Natural History under the catalogue number AMNH 560. 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. The amount of material was great, it composed of several jumbled partial skeletons. It was not all prepared at once, but a considerable amount of it was cleaned up by Jacob Geismar under Cope's direction throughout the 1870s to 1890s. 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