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Name means: Bent Reptile


Species: dispar

Range: Late Jurassic (Tithonian, 150-145 MYA) from Utah, Wyoming, Colorado, Oklahoma, possibly Germany

Size estimate: 18-25 ft length, 800-1000 lbs

Discovery: Othniel Charles Marsh, 1885

Classification: dinosauria, ornithischia, ornithopoda, iguanodontia, ankylopollexia


As one of the rarer plant eaters of the Morrison Formation, Camptosaurus has puzzled scientists for a long time. Several skeletons scientists once thought belonged to this animal now have new classifications thanks to better information. Better skeletons of Camptosaurus itself have also solved some problems. For example, Camptosaurus’ head had a more triangular shape than seen here. The skull used as a model for this sculpture belongs to a related animal called Theiophytalia. Scientists are still working out how all the new information fits together.


Camptosaurus was a medium-sized ornithopod that usually walked on all fours. Its overall body shape resembled Dryosaurus, but its greater size and change of gait might show a shift in diet. It may have preferred tougher food than Dryosaurus and needed a larger gut to digest it.


Popular tradition describes the thumb spike as a means of defense. Though Camptosaurus might have used it for that purpose, the spike’s small size makes it a poor weapon. When threatened, it probably ran away on its hind legs. The thumb spike might have helped the animal get food instead. Camptosaurus had rough teeth for chewing tough plant material. It also had a narrow snout that suggests a specific dietary preference. The spike might have helped it pry apart stems to get at more nutritious layers inside.

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