Camarasaurus lewisi

Camarasaurus lewisi is a species of sauropod dinosaur from the Upper Jurassic of the United States. It was named by James A. Jensen in 1988. C. lewisi was originally placed in its own genus, Cathetosaurus, but in 1996 it was reclassified as a species of Camarasaurus; most researchers since have considered it to be one of the four valid species of Camarasaurus. Two unpublished studies have since argued that the genus Cathetosaurus should be reinstated, whereas two other studies have argued that C. lewisi may be a junior synonym of another species of Camarasaurus. Description C. lewisi is the smallest species assigned to Camarasaurus; despite representing a very old individual, the holotype specimen is roughly 26% smaller than C. supremus, with a humerus long. The possible C. lewisi specimen SMA 0002 also represents a fully mature individual, but is exceptionally small, with a humerus only long. It is possible that the size difference reflects sexual dimorphism. Frank Seebacher estimated the length of C. lewisi as and mass as 11.7 tonnes, whereas Gregory S. Paul estimated the length of C. lewisi as and mass as 10 tonnes. C. lewisi was relatively long-necked compared to most specimens of Camarasaurus.