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This is a list of dinosaurs whose remains have been recovered from North America. North America has a rich dinosaur fossil record with great diversity of dinosaurs. This may not mean the dinosaurs were more diverse or abundant; it may be simply because substantial resources have been devoted to the North American fossil record. During the Triassic period, dinosaurs such as ''Coelophysis'', ''Chindesaurus'', ''Gojirasaurus'', and ''Tawa'' lived in North America. Fossils of ''Tawa'' have also been found in South America, which has important indications about paleogeography. During the Early Jurassic Period, dinosaurs such as ''Dilophosaurus'', ''Anchisaurus'', ''Ammosaurus'', ''Megapnosaurus'' (formerly known as ''Syntarsus''), and the early thyreophoran ''Scutellosaurus'' lived in North America. The latter is believed to have been the ancestor of all stegosaurs and ankylosaurs. The Middle Jurassic is the only poorly represented time period in North America, although several Middle Jurassic localities are known from Mexico. Footprints, eggshells, teeth, and fragments of bone representing theropods, sauropods, and ornithopods have been found, but none of them are diagnostic to the genus level. The Late Jurassic of North America, however, is the exact opposite of the Middle Jurassic. The Late Jurassic Morrison Formation is found in several U.S. states, including Colorado, Utah, Wyoming, Montana, New Mexico, Oklahoma, South Dakota, and Texas. It is notable as being the most fertile single source of dinosaur fossils in the world. The roster of dinosaurs from the Morrison is impressive. Among the theropods, ''Allosaurus'', ''Saurophaganax'', ''Torvosaurus'', ''Ceratosaurus'', ''Coelurus'', ''Ornitholestes'', ''Tanycolagreus'', ''Stokesosaurus'', and ''Marshosaurus'' are found in the Morrison. An abundance of sauropods has been found there, including ''Apatosaurus'', ''Diplodocus'', ''Barosaurus'', ''Brachiosaurus'', ''Camarasaurus'', and ''Amphicoelias'', which is possibly the largest known dinosaur ever to exist. Two genera of stegosaurs, ''Stegosaurus'' and ''Hesperosaurus'', have been found there. Finally, ornithopods found in the Morrison include ''Dryosaurus'', ''Camptosaurus'', ''Drinker'', ''Othnielia'', and ''Othnielosaurus''. During the Early Cretaceous, new dinosaurs evolved to replace the old ones. Sauropods were still present, but they were not as diverse as they were in the Jurassic Period. Theropods from the Early Cretaceous of North America include dromaeosaurids such as ''Deinonychus'' and ''Utahraptor'', ''Acrocanthosaurus'', and ''Microvenator''. Sauropods included ''Astrodon'', ''Brontomerus'', and ''Sauroposeidon''. Ornithischians were more diverse than they were in the Jurassic Period. ''Tenontosaurus'', ''Hypsilophodon'', ''Iguanodon'', ''Protohadros'', and ''Eolambia'' are some of the ornithopods that lived during this time period. Ankylosaurs replaced their stegosaur cousins in the Cretaceous. Ankylosaurs from the Early Cretaceous of North America include ''Sauropelta'' and ''Gastonia''. Therizinosaurs such as ''Falcarius'' are also known from the Early Cretaceous of North America. Finally, the Late Cretaceous Period, the greatest abundance and diversity of dinosaurs of all time lived in North America. During the early part of the Late Cretaceous, the therizinosaur ''Nothronychus'' and the ceratopsian ''Zuniceratops'' lived. During the Campanian stage of the Late Cretaceous, an enormous diversity of dinosaurs is known. Theropods included the tyrannosaurs ''Albertosaurus'', ''Gorgosaurus'', ''Daspletosaurus'', ''Teratophoneus'', ''Bistahieversor'', and ''Appalachiosaurus'', and the dromaeosaurids ''Dromaeosaurus'', ''Saurornitholestes'', ''Atrociraptor'', and ''Bambiraptor''. Ceratopsians, such as ''Pachyrhinosaurus'', ''Styracosaurus'', ''Centrosaurus'' ''Monoclonius'', ''Brachyceratops'', ''Pentaceratops'', and ''Leptoceratops'' also existed. Among hadrosaurs,'' Hypacrosaurus, Gryposaurus, Kritosaurus, Parasaurolophus'', ''Corythosaurus'', ''Lambeosaurus'', ''Saurolophus'', and ''Prosaurolophus'' existed. During the latest Cretaceous, the Maastrichtian age, the diversity of dinosaurs saw a decline from the preceding Campanian stage. North American herbivorous dinosaurs from this time period include the titanosaur sauropod ''Alamosaurus'', the ceratopsians ''Triceratops'' and ''Torosaurus'', the pachycephalosaurs ''Pachycephalosaurus'', ''Stygimoloch'', ''Dracorex'', and ''Stegoceras'', and the hadrosaur ''Edmontosaurus''. Predatory dinosaurs from this time period included the tyrannosaurids ''Tyrannosaurus,'' ''Dryptosaurus'', and ''Nanotyrannus'' (which may just be a juvenile of the former), and the troodontid ''Troodon''. : ==Key== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「List of North American dinosaurs」の詳細全文を読む スポンサード リンク
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