Megalosaurus

Megalosaurus (meaning "great lizard", from Greek μέγας, megas, meaning 'big', 'tall' or 'great' and σαῦρος, sauros, meaning 'lizard') is an extinct genus of large carnivorous theropod dinosaurs of the Middle Jurassic Epoch (Bathonian stage, 166 million years ago) of southern England. Although fossils from other areas have been assigned to the genus, the only certain remains of Megalosaurus come from Oxfordshire and date to the late Middle Jurassic. The earliest remains of Megalosaurus were described in the 17th century, and were initially interpreted as the remains of elephants or giants. Megalosaurus was named in 1824 by William Buckland, becoming the first genus of dinosaur to be validly named (other than birds, not then recognized as dinosaurs). The type species is M. bucklandii, named in 1827 by Gideon Mantell, after Buckland. In 1842, Megalosaurus was one of three genera on which Richard Owen based his Dinosauria, along with Iguanodon and Hylaeosaurus. On Owen's directions a model was made as one of the Crystal Palace Dinosaurs, which greatly increased the public interest for prehistoric reptiles. Over 50 other species would eventually be classified under the genus; at first, this was because so few types of dinosaur had been identified, but the practice continued even into the 20th century after many other dinosaurs had been discovered. Today it is understood that none of these additional species was directly related to M. bucklandii, which is the only true Megalosaurus species. Because a complete skeleton of it has never been found, much is still unclear about its build. The first naturalists who investigated Megalosaurus mistook it for a gigantic quadrupedal lizard 20 metres (66 ft) in length. In 1842, Owen concluded that it was no longer than 9 metres (30 ft). Modern scientists were able to obtain a more accurate picture, by comparing Megalosaurus with its direct relatives in the Megalosauridae. Megalosaurus was about 6 metres (20 ft) long, weighing about 700 kilograms (1,500 lb). It was bipedal, walking on stout hindlimbs, its horizontal torso balanced by a horizontal tail. Its forelimbs were short, though very robust. Megalosaurus had a rather large head, equipped with long curved teeth. It was generally a robust and heavily muscled animal. At the time Megalosaurus lived, Europe formed an island archipelago bounded by then narrow Atlantic Ocean and Tethys Ocean, with Megalosaurus inhabiting an island formed by the London–Brabant Massif, where it likely served as the apex predator of its ecosystem, coexisting with other dinosaurs like the large sauropod Cetiosaurus, stegosaurs, ankylosaurs, and heterodontosaurids.