ବ୍ୟବହାରକାରୀ:Snip1/ଉତ୍ତର ଆମେରିକୀୟ ଡାଇନୋସର ଗୁଡ଼ିକର ତାଲିକା
From Wikipedia, the free encyclopedia
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 wasn't as great as 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.