Camptosaurus

Phylogeny: Dinosauria > Ornithischia > Genasauria > Neornithischia > Cerapoda > Ornithopoda > Iguanodontia > Ankylopollexia > Camptosauridae

Overview: In the late 1870’s, a fossil hunter working on behalf of the famed Othniel C. Marsh came across the fossilized remains of a then unknown ornithopod dinosaur. The discovery was made in the state of Wyoming, within the rocks of the Late Jurassic-aged Morrison Formation. Marsh went on to give it a formal description in 1879, calling it Camptonotus, meaning “flexible back” in Greek, referring to the unusually flexible vertebrae it sported between its pelvic bones. Camptonotus was later recognized to already be in use for an insect, so Marsh would formally rename the dinosaur in 1885. The name Camptosaurus, or “flexible lizard”, refers to the same anatomical trait. Numerous other Camptosaurus specimens would be found over the next century, mainly within the Morrison Formation, but fossils from elsewhere in the world are also suspected to belong to the genus. The genus Uteodon, also known from the United States, and England’s Cumnoria are thought by some to be junior synonyms of Camptosaurus, but not all researchers are convinced.

Camptosaurus was often classified as a potential early iguanodontid in older studies, but later, the genus was referred to its own family – the Camptosauridae. Some similar dinosaur genera such as Draconyx and the aforementioned Cumnoria and Uteodon may belong to this group, but there is a lot of disagreement on this matter. Camptosaurus itself seems to have been an iguanodont that was more derived than Dryosaurus, a genus it probably coexisted with. Similar to Dryosaurus, this genus appears to have been a strictly bipedal animal, based on its limb morphology. Camptosaurus seems to have been significantly more robust and bulky than Dryosaurus. The snout was narrow, ending in a keratinous beak, implying a selective diet of low-level plants like ferns and young shoots. It itself may’ve been a source of food for predatory dinosaurs like Ceratosaurus and Allosaurus. The rocks of the Morrison Formation preserve a semi-arid climate that was also home to other dinosaurs like Stegosaurus, Camarasaurus, Brachiosaurus, Diplodocus, Apatosaurus, and Ornitholestes.