Seeley introduced the division between the two groups. Some of the quadrupedal saurischians developed into the largest land animals in history, including Diplodocus ( perhaps reaching lengths of 100 feet or more) and Brachiosaurus ( perhaps weighing as much as 130,000 pounds ). The saurischians or “lizard hipped,” including carnivorous bipedal forms (e.g., theropods such as Tyrannosaurus) and herbivorous bipedal and quadrupedal forms (e.g., sauropods). The ornithischians were “bird hipped” as well as being herbivores, including both bipedal and quadrupedal forms. With the discovery of many new species since the 1840s, scientists have divided the Dinosauria into two major groups: the Ornithischia and the Saurischia, with the distinction based on the construction of the pelvis. Many species apparently roamed the land easily despite their size, and some were quite social, traveling in herds, building nests, and caring for their young (Macdougall 1996). In fact, many dinosaurs were very agile (even the large ones). Modern research has disproved the old concept that dinosaurs were slow-moving, dim-witted, solitary creatures, forced to wade about in swamps because their great bulk could not be supported on land. Since Owen’s time, further data show that dinosaurs were animals that evolved into many sizes and shapes. The term “dinosaur” was invented by Sir Richard Owen in 1842 to describe these “terrible lizards,” specifically Megalosaurus, Iguanodon, and Hylaeosaurus, the only three dinosaurs known at the time. For example, Tyrannosaurus rex is so well-known that it seems to be one of the first tongue twisters that children master. Some consider the predators that preyed on these giants to be even more spectacular. Brachiosaurus lived from 150 to 145 million years ago. The type species of Brachiosaurus is known from two partial skeletons recovered in Colorado and Utah. Riggs discovered the first known Brachiosaurus in 1900 near Grand Junction, Colorado, just outside Colorado National Monument. Recently, several giant titanosaurians (e.g., Argentinosaurus) have been found that surpassed Brachiosaurus in terms of sheer mass.
For instance, Brachiosaurus was the largest known dinosaur for many decades. Learn more about events in the Jurassic Periodĭinosaurs have dominated the popular conception of paleontology, sometimes to the extent of seeming almost synonymous with the word “fossil.” Dinosauria, the scientific version of the term dinosaur, includes by far the largest terrestrial animals ever to have lived. rex and birds descended from the same group-Theropoda. Moreover, the oldest known fossil of a bird is from the Jurassic. Good thing they weren’t carnivores! However, carnivorous dinosaurs also diversified during the Jurassic. To do the “ Diplodocus dash” (head to foot) would take you four seconds. Let’s say you can do the 100-meter dash in 14 seconds. To get a sense of how large these animals were, imagine sprinting as fast as you can. Huge sauropod herbivores (such as 87-foot long Diplodocus) and carnivores (such as 35-foot long Allosaurus) emerged. The Jurassic Period was a golden time for dinosaurs, which flourished for 180 million years. In 1839 Leopold von Buch redefined the Jurassic as a system in its own right (Eicher 1976). Jurassic age fossil Camarasaurus skull, Dinosaur National Monument, Colorado and Utah.Īlexander von Humboldt, a German pioneer geologist, first coined this term “Jurassic” in 1795 for the strata of the Jura Mountains in northern Switzerland.