The front limbs were almost as long as the back, and each back foot had five toes.įamily: Barapasauridae: The next most primitive sauropod, Barapasaurus, is known from parts of several skeletons from the Early Jurassic of India. ![]() It had a bulky body and its legs were long and straight. The only skeleton is missing the head, neck, and much of the tail. Sauropod heads, which were lightly built and fragile, often broke off after death.įamily: Vulcanodontidae: The earliest true sauropod is Vulcanodon from the Early Jurassic of Zimbabwe. Sauropod skulls were either blunt (flat) or tapering (came to a point) and the nostrils were back from the tip of the snout. Also, to add strength they had more vertebrae where the pelvis and spine joined. Their vertebrae (bones in the spine) had deep hollows to lighten the weight of their backbone. They lost the grasping function of their front feet, and their legs looked like long, straight columns. Sauropods had many features because of their large size. Being large also helped them reach food, such as leaves in treetops, that was too high for smaller plant-eaters. ![]() Like today's elephants, sauropods had little fear of predators because of their size. All sauropods were giants and four-legged plant-eaters. This probably happened sometime in the Late Triassic, when sauropods first appeared. The second group of sauropodomorphs, the Sauropoda, probably came from an ancestor much like Thecodontosaurus. They were 25 to 30 feet long with narrow, long snouts, long necks, powerful front and back limbs, and heavy bodies. Seeley called these dinosaurs ornithischian, or "bird-hipped" dinosaurs.įamily: Plateosauridae: This is the best-known family of prosauropods, with animals found in Europe, China, and North and South America. In other dinosaurs, the pubes extended down and back, running beneath and parallel to the ischia, as they do in birds. This is why Seeley called them saurischian, or "lizard-hipped" dinosaurs. In some dinosaurs, the pubes extended down and forward, as they do in lizards. The left and right ischia (singular: ischium) extended down and back beneath the ilia and behind the pubes. The left and right pubes (singular: pubis) extended down beneath the ilia. The left and right ilia (singular: ilium) firmly gripped the spine in the sacrum. Birds belong to the saurischian dinosaur clade.Īs in all land animals, there were three bones in each side of the pelvis. Both orders probably had a common ancestor that lived sometime during the Middle Triassic. Harry Govier Seeley split dinosaurs into two groups, the Order Saurischia ("lizard-hipped" dinosaurs) and the Order Ornithischia ("bird-hipped" dinosaurs).
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