That sauropod fossils have been found on every continent suggests they were able to adapt to diverse environments. Prosauropods roamed the earth from 210 to 190 million years ago, during the late Triassic and early Jurassic periods. The fossil record indicates that members of this group were the first dinosaurs to rely on plants for food. As their numbers declined, prosauropods were replaced by larger plant-eating sauropods. There are two kinds of dinosaur hips.
Paleontologists use the difference to divide dinosaurs into two large groups.
In one group, the two bones called the pubis and the ischium are positioned as seen in the sauropod pelvis in the movie. This phrase was chosen because this hip structure resembles that of present-day reptiles, though these two groups are not closely related. The other group of dinosaurs is called Ornithischia. Back to Highlights Pterosaurs Pterosaurs were flying reptilian cousins of the dinosaurs. Many of the pterosaurs' skeletal modifications paralleled those of birds.