CAMPTOSAURUS

any of a genus of large herbivorous dinosaurs found as fossils in western Europe and western North America in Late Jurassic to Early Cretaceous rocks (from about 163 to 97.5 million years ago). Camptosaurus, an ornithopod (a group of relatively primitive bipeds), varied in length from 2 to 6 m (6 to 20 feet). It had very strong hind limbs and smaller forelimbs that were strong enough to support the animal if it chose to progress on all fours, as it might while feeding. The heavy tail may have been employed to support the animal when it stood erect. The skull was low, long, and massive, with large temporal and nasal openings. The lower jaw was shorter than the upper, but a distinctive jaw suspension ensured that the cheek teeth were brought into apposition in chewing. The teeth were broad and leaf-shaped and were present only at the sides of the jaws. A beaklike structure, which, scientists speculate, probably was covered by horny pads in life, was effective in getting plant material into the mouth, where it was cut by the cheek teeth.