Tyrannosaurus rex ("tyrant lizard king"), also recognized colloquially as The King of the Dinosaurs, was a huge carnivorous theropod dinosaur from the Upper Maastrichtian, the last stage of the Cretaceous time, 65–66 million years ago. Its fossil leftovers are rare — as of 2005 only 30 specimens had been found1, including three total skulls. The first specimens found played a significant role in the Bone Wars. T. rex is the best known carnivorous dinosaur, chiefly because it was consideration to be the largest to have ever existed for a long time. While there have been sensationalistic claims of new, larger theropods "dethroning" T. rex as the King of the Dinosaurs, proof remains scant and open to debate. T. rex will very likely remain a subject of ongoing scientific investigate and popular culture.
The first specimen (a partial vertebra) was establish by Edward Cope in 1892 and was described as Manospondylus gigas. It was assigned to Tyrannosaurus rex in 1912 by Henry Osborn. Barnum Brown, helper curator of the American Museum of Natural History, establishes the second T. Rex Skeleton in Wyoming in 1900. This specimen was at first named Dynamosaurus imperiosus in the same paper in which Tyrannosaurus rex was described. Were it not for page order, Dynamosaurus would have turn out to be the official name. The original "Dynamosaurus" material resides in the collections of the Natural History Museum, London.
Up to 13 meters (43 feet) in length and 4–7 tons in weight, T. rex was one of the main carnivorous dinosaurs of all time. Compared to additional carnivorous dinosaurs, the skull of Tyrannosaurus is a lot modified. Many of the bones are compound together, preventing group between them. The bones themselves are much more massive than is typical of a theropod, and the jagged teeth, far from being bladelike, are massive and oval in cross-section. Heavy wear and the bite script found on bones of other dinosaurs indicate that these teeth could bite into solid bone. The teeth are often damaged or broken at the tips from heavy use but, unlike mammals, were continually full-grown and shed all through the life of the animal. Compared to other giant carnivorous dinosaurs such as Allosaurus, Tyrannosaurus appears to have had a sizeable brain, but it was almost certainly not chiefly intelligent by mammalian standards.
The neck was short and very a lot muscled. The arms of T. rex were small, maybe to make up for the weight of its huge head, but were very sturdy. Paleontologists continue to argue about what reason, if any, they served. They may have served to grab the female during sex, and surely helped the animal to get up, temporarily behind the front body like the struts of a detached truck trailer. The legs were comparatively long and slender for an animal of this size. Recent investigate suggests that an adult Tyrannosaurus could not run much, but juveniles might have been with no trouble as fast as a modern lion. Most scientists and paleontologists adults were not fast runners. The configuration of its hip bone relative to the legs and spine propose a muscle tissue expansion and posture that would have enabled the animal to run close to 30 mph (50 km/h) in adulthood. Evidence of its prey in fossils and migrating patterns propose this animal probably had to have been able to sustain a speed strong enough to hunt its prey. To recompense for its immense bulk, the center of many bones were hollowed out. This significantly reduced the weight of the skeleton while maintaining much of the power of the bones.