Camptosaurus dispar
Camptosaurus dispar was a stocky plant-eating dinosaur with a barrel-shaped body, short but powerfully built forelimbs and long, muscular hind legs. Its skull was low and elongated, ending in a toothless horny beak used to crop vegetation.
Camptosaurus
Camptosaurus dispar
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Quick facts
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Weight
500–1000 kg
Length
5–7.9 m
Diet
Herbivore
Period
Jurassic
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500–1000 kg
5–7.9 m
Jurassic
Both bipedal and quadrupedal
1.5–2 m
25 km/h
Herbivore
Regions where fossils have been found, shown by present-day continent.
The timeline shows the whole age of dinosaurs – and how much time has passed since. The glowing part is when Camptosaurus lived.
million years ago
Lived 156–145 million years ago
If the whole age of dinosaurs were a single day, Camptosaurus lived at 13:05.
Chapter • Meet the dinosaur
Camptosaurus dispar was a stocky plant-eating dinosaur with a barrel-shaped body, short but powerfully built forelimbs and long, muscular hind legs. Its skull was low and elongated, ending in a toothless horny beak used to crop vegetation. Behind the beak sat tightly packed rows of leaf-shaped cheek teeth that ground against one another while the animal chewed, with fleshy cheeks holding the food inside the mouth. The hand had five fingers, the middle three bearing broad hoof-like unguals that could take the animal's weight on the ground, while the thumb was short and conical – an early, far smaller version of the famous thumb spike of Iguanodon. The tail was held straight out behind the body as a counterweight, never dragging along the ground.
Chapter • Where it lived
Camptosaurus lived in the Late Jurassic, roughly 156–145 million years ago, in what is now the western United States. Its fossils come almost entirely from the Morrison Formation of Wyoming, Utah, Colorado and Oklahoma, with the richest sites at Como Bluff in Wyoming and the quarry at Dinosaur National Monument in Utah. The setting was a vast plain crossed by meandering rivers, with seasonally flooded floodplains and drier intervals between rains. Ferns, horsetails, cycads, ginkgoes and conifers grew in gallery forests along the watercourses – exactly the sort of low to medium-height vegetation that the beak and tooth rows of Camptosaurus were built to process.
Chapter • Wild behavior
Diurnal
Several individuals have been recovered from the same bone-bearing layers, which has been read as evidence that Camptosaurus may at least sometimes have moved in groups. The evidence is weak, however: bone accumulations can equally well form when river currents gather carcasses in one spot. No trackways, nesting sites or other finds confirm herding in this species, so the extent of its social life remains uncertain.
The name means roughly "bent lizard", referring to the curved thigh bones of the first specimens.
Othniel Charles Marsh named the animal Camptonotus in 1879 but had to rename it Camptosaurus in 1885, because Camptonotus was already taken by a cricket.
The first fossils were collected by William Harlow Reed at Quarry 13, Como Bluff, Wyoming.
Camptosaurus could probably walk on all fours and rear up on its hind legs to run or reach higher plants.
The three central fingers carried wide, hoof-like claws – clear evidence that the hand was used for walking.
It shared its landscape with Allosaurus, Stegosaurus, Apatosaurus and Diplodocus in the Morrison Formation.
Charles Gilmore published a classic monograph on Camptosaurus in 1909 that researchers still cite today.
As an ankylopollexian, Camptosaurus is regarded as an early relative of the later iguanodonts and duck-billed dinosaurs.
Chapter • Scientific place
Zootaxa (Magnolia Press)
Reviewed: 9/6/2026
Peer-reviewed taxonomic revision that evaluates every species referred to Camptosaurus and establishes the classification and validity of the type species C. dispar within Ankylopollexia.
Open sourceThe Paleobiology Database
Reviewed: 9/6/2026
Database taxon page listing the recorded fossil collections, Morrison Formation localities in the western United States, and the stratigraphic (Kimmeridgian–Tithonian) range of the species.
Open sourceSedimentary Geology (Elsevier)
Reviewed: 9/6/2026
Peer-reviewed study of Morrison Formation plant fossils and climate reconstructing the seasonally dry floodplain and riparian gallery-forest palaeoenvironment Camptosaurus inhabited.
Open sourceNatural History Museum, London
Reviewed: 9/6/2026
Museum reference entry documenting Camptosaurus as a herbivorous ornithopod that cropped low- to medium-height vegetation with its beak and tooth batteries.
Open sourceSedimentary Geology (Elsevier)
Reviewed: 9/6/2026
Extinct taxon; conservation status NE
Open sourceAnnals of Carnegie Museum
Reviewed: 9/6/2026
Peer-reviewed monographic treatment of Camptosaurus material that redescribes the anatomy of C. dispar and analyses its posture and locomotion, serving as the general overview source.
Open sourceAnnals of Carnegie Museum
Reviewed: 9/6/2026
Peer-reviewed monographic treatment of Camptosaurus material that redescribes the anatomy of C. dispar and analyses its posture and locomotion, serving as the general overview source.
Open sourceAnnals of Carnegie Museum
Reviewed: 9/6/2026
Peer-reviewed monographic treatment of Camptosaurus material that redescribes the anatomy of C. dispar and analyses its posture and locomotion, serving as the general overview source.
Open sourceAnnals of Carnegie Museum
Reviewed: 9/6/2026
Peer-reviewed monographic treatment of Camptosaurus material that redescribes the anatomy of C. dispar and analyses its posture and locomotion, serving as the general overview source.
Open source