List of North American dinosaurs

The earliest potential record of dinosaurs in North America comes from rare, unidentified (possibly theropod) footprints in the Middle-Late Triassic Pekin Formation of North Carolina.^[1] However, the most reliable early record of North American dinosaurs comes from fragmentary saurischian fossils unearthed from the Late Triassic Dockum Group of Texas.^[2] Later in the Triassic period, dinosaurs left more recognizable remains, and could be identified as specific genera. Examples include Coelophysis, Chindesaurus, Gojirasaurus, and Tawa. Fossils of Tawa-like dinosaurs have also been found in South America, which has implications for paleogeography. During the Early Jurassic, dinosaurs such as Dilophosaurus, Anchisaurus, Podokesaurus, and the early thyreophoran Scutellosaurus lived in North America. The latter is thought ancestral to all stegosaurs and ankylosaurs. The Middle Jurassic is the only poorly represented 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, 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, Brontosaurus and Amphicoelias. Three genera of stegosaurs, Alcovasaurus, Stegosaurus and Hesperosaurus, have been found there. Finally, neornithischians found in the Morrison include Camptosaurus, Dryosaurus, and Nanosaurus.

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, the carnosaur Acrocanthosaurus, and the coelurosaur Microvenator. Sauropods included Astrodon, Brontomerus, and Sauroposeidon. Ornithischians were more diverse than they were in the Jurassic Period. Tenontosaurus, Dakotadon, and Hippodraco 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, during the Late Cretaceous Period, dinosaurs continued to diversify, with the Cenomanian stage seeing the rise of hadrosaurs such as Eolambia and Protohadros, as well as tyrannosaurs such as Moros intrepidus, which would make the carnosaurs, like Siats, as the continent's apex predators. These groups continued to thrive into the Turonian stage, in which therizinosaurs like Nothronychus, and larger ceratopsians such as 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 and Pentaceratops also existed. Among hadrosaurs, Hypacrosaurus, Gryposaurus, Kritosaurus, Parasaurolophus, Corythosaurus, Lambeosaurus 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 Bravoceratops, Regaliceratops, Triceratops, Leptoceratops, Torosaurus, Ojoceratops, Nedoceratops, and Tatankaceratops (the latter two possible synonyms of Triceratops), the pachycephalosaurs Pachycephalosaurus, Sphaerotholus, Stygimoloch, and Dracorex (the latter two possible synonyms of Pachycephalosaurus), the hadrosaurs Augustynolophus, Saurolophus, and Edmontosaurus, the neornithischian Thescelosaurus, the ankylosaurid Ankylosaurus and the nodosaurids Denversaurus, Glyptodontopelta, and Edmontonia. Predatory dinosaurs from this time period included the tyrannosauroids Tyrannosaurus, Nanotyrannus, and Dryptosaurus, the ornithomimids Ornithomimus, Dromiceiomimus, Struthiomimus, the oviraptorosaurs Anzu, Leptorhynchos and Ojoraptorsaurus, the troodontids Pectinodon, Paronychodon and Troodon, the coelurosaur Richardoestesia and the dromaeosaurs Acheroraptor and Dakotaraptor.

The only recorded find of a dinosaur fossil in Central America consists of a single femur discovered from mid Cretaceous-aged deposits in Comayagua Department in the central part of Honduras. The fossil had been found in January, 1971 by Bruce Simonson and Gregory Horne, though it was later sent to the National Museum of Natural History, USA where it is deposited under catalogue number USNM PAL 181339. The discovery was not formally described until 1994 where it was identified as the femur of a small hadrosaur or iguanodontid, probably the former.^[3] The first report of a dinosaur from Central America ever however was a newspaper article published in August of 1933 by Canada's Montreal Gazette, though the story was picked up by several American newspapers. The fossil was an isolated metatarsus that had been collected by University of Pennsylvania explorer George Mason from woods near Olanchito, Honduras, though a vertebra was also mentioned to be found by locals. The bones have since been lost and their true identity remains indeterminable.^[4]

• The genus must appear on the List of dinosaur genera.
• At least one named species of the creature must have been found in North America.