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List of North American dinosaurs facts for kids

Kids Encyclopedia Facts

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.

History

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. However, the most reliable early record of North American dinosaurs comes from fragmentary saurischian fossils unearthed from the Upper Triassic Dockum Group of Texas. Later in the Triassic period, dinosaurs left more recognizable remains, and could be identified as specific genera. Examples of later Triassic North American dinosaur genera include Coelophysis, Chindesaurus, Gojirasaurus, and Tawa. Fossils of Tawa-like dinosaurs have also been found in South America, which has important indications about paleogeography. During the Early Jurassic Period, dinosaurs such as Dilophosaurus, Anchisaurus, Coelophysis (formerly known as Megapnosaurus), 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, Brontosaurus and Amphicoelias. Three genera of stegosaurs, Alcovasaurus, Stegosaurus and Hesperosaurus, have been found there. Finally, ornithopods 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, Protohadros 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, as well as tyrannosaurs such as Moros intrepidus, which would eventually replace 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, Nedoceratops, Tatankaceratops (the latter two possible species of Triceratops), and Ojoceratops, the pachycephalosaurs Pachycephalosaurus, Stygimoloch, Dracorex, and Sphaerotholus, the hadrosaurs Augustynolophus, Saurolophus and Edmontosaurus, the ornithopod Thescelosaurus the ankylosaur Ankylosaurus and the nodosaurs Denversaurus, Glyptodontopelta and Edmontonia. Predatory dinosaurs from this time period included the tyrannosaurids Tyrannosaurus, Nanotyrannus (which may just be a juvenile of the former) and Dryptosaurus, the ornithomimids Ornithomimus, Dromiceiomimus, Struthiomimus, the oviraptorids 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 Middle Cretaceous age 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. 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.

Criteria for inclusion

  • 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.
  • This list is a complement to Category:Mesozoic dinosaurs of North America.

List of North American dinosaurs

Valid genera

Name Year Formation Location Notes Images
Abydosaurus 2010 Cedar Mountain Formation (Early Cretaceous, Albian)  United States
( Utah)
Had a short domed crest on its skull similar to that of Giraffatitan Abydosaurus NT.jpg
Acantholipan 2018 Pen Formation (Late Cretaceous, Santonian)  Mexico
( Coahuila)
Known to possess spike-like osteoderms Acantholipan gonzalezi.jpg
Achelousaurus 1994 Two Medicine Formation (Late Cretaceous, Campanian)  United States
( Montana)
Combines long spikes on the top of its frill and a low keratinous boss over its eyes and nose Achelousaurus dinosaur.png
Acheroraptor 2013 Hell Creek Formation (Late Cretaceous, Maastrichtian)  United States
( Montana)
One of the geologically youngest dromaeosaurids Acheroraptor NT small.jpg
Acristavus 2011 Two Medicine Formation, Wahweap Formation (Late Cretaceous, Campanian)  United States
( Montana
 Utah)
Uniquely for a hadrosaurid, it lacked any ornamentation on its skull Acristavus.jpg
Acrocanthosaurus 1950 Antlers Formation, Arundel Formation, Cloverly Formation, Twin Mountains Formation (Early Cretaceous, Aptian to Albian)  United States
( Maryland
 Oklahoma
 Texas
 Wyoming)
Possessed elongated neural spines that would have supported a low sail or hump in life Acrocanthosaurus restoration.jpg
Acrotholus 2013 Milk River Formation (Late Cretaceous, Santonian)  Canada
( Alberta)
Had a tall, oval-shaped dome Acrotholus NT.jpg
Adelolophus 2014 Wahweap Formation (Late Cretaceous, Campanian)  United States
( Utah)
Potentially a close relative of Parasaurolophus Adelolophus LM.png
Agujaceratops 2006 Aguja Formation (Late Cretaceous, Campanian)  United States
( Texas)
The type species was originally assigned to the genus Chasmosaurus Agujaceratops life restoration.jpg
Ahshislepelta 2011 Kirtland Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Relatively small compared to other North American ankylosaurs Ahshislepelta LM.png
Akainacephalus 2018 Kaiparowits Formation (Late Cretaceous, Campanian)  United States
( Utah)
Much of the skeleton is known, including the entirety of the skull Akainacephalus (updated).png
Alamosaurus 1922 Black Peaks Formation, El Picacho Formation, Evanston Formation?, Javelina Formation, North Horn Formation, Ojo Alamo Formation (Late Cretaceous, Maastrichtian)  United States
( New Mexico
 Texas
 Utah
 Wyoming?)
The only titanosaur confirmed to have crossed into North America. One of the largest dinosaurs known from the continent Alamosaurus-sanjuanensis.jpg
Alaskacephale 2006 Prince Creek Formation (Late Cretaceous, Maastrichtian)  United States
( Alaska)
Had an array of polygonal nodes on its squamosal Alaskacephale gangloffi copia.jpg
Albertaceratops 2007 Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Possessed long brow horns and a bony ridge over its nose Albertaceratops BW.jpg
Albertadromeus 2013 Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
The proportions of its hindlimb suggest a cursorial lifestyle Albertadromeus syntarsus.png
Albertavenator 2017 Horseshoe Canyon Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
Its discovery suggests the diversity of small dinosaurs may be higher than previously thought Albertavenator LM.png
Albertonykus 2009 Horseshoe Canyon Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
May have used its specialized forelimbs to dig into tree trunks for termites Albertonykus borealis.jpg
Albertosaurus 1905 Horseshoe Canyon Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
Known from more than thirty specimens, twenty-six of which are preserved together Albertosaurus NT small.jpg
Aletopelta 2001 Point Loma Formation (Late Cretaceous, Campanian)  United States
( California)
Would have lived in present-day Mexico; its fossils were only found in California due to the shifting of tectonic plates Aletopelta NT.jpg
Allosaurus 1877 Morrison Formation (Late Jurassic, Kimmeridgian to Tithonian)  United States
( Colorado
 Utah
 Wyoming)
Multiple specimens have been discovered, making it well-known both popularly and scientifically. At least two species are known from the United States, with a third described from Portugal Allosaurus Revised.jpg
Ampelognathus 2023 Lewisville Formation (Late Cretaceous, Cenomanian)  United States
( Texas)
More closely related to iguanodonts than to the morphologically similar "hypsilophodonts" Ampelognathus.png
Amphicoelias 1878 Morrison Formation (Late Jurassic, Tithonian)  United States
( Colorado)
Originally believed to date from the Cretaceous Amphicoelias17DB2.jpg
Anasazisaurus 1993 Kirtland Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
May have been a second species of Kritosaurus Anasazisaurus LM.png
Anchiceratops 1914 Horseshoe Canyon Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Had a long, rectangular frill ringed by short, triangular spikes Anchiceratops dinosaur.png
Anchisaurus 1885 Portland Formation (Early Jurassic, Hettangian to Sinemurian)  United States
( Connecticut
 Massachusetts)
Some possible remains were originally misidentified as human skeletons Anchisaurus NT.jpg
Angulomastacator 2009 Aguja Formation (Late Cretaceous, Campanian)  United States
( Texas)
The tip of its jaw was angled 45 degrees downward, with the tooth row bent to match Angulomastacator LM.png
Animantarx 1999 Cedar Mountain Formation (Early Cretaceous to Late Cretaceous, Albian to Cenomanian)  United States
( Utah)
Its holotype was discovered during a radiological survey of a fossil site; no bones were exposed before it was excavated Animantarx 04829.JPG
Ankylosaurus 1908 Ferris Formation, Frenchman Formation, Hell Creek Formation, Lance Formation, Scollard Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta
 Saskatchewan)
 United States
( Montana
 Wyoming)
The largest and most well-known ankylosaur Ankylosaurus magniventris by sphenaphinae.png
Anodontosaurus 1929 Horseshoe Canyon Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta)
Originally mistakenly believed to have been toothless Anodontosaurus LM.png
Anzu 2014 Hell Creek Formation (Late Cretaceous, Maastrichtian)  United States
( Montana
 North Dakota
 South Dakota)
Large and known from considerably good remains. Preserves evidence of a tall head crest Anzu wyliei.jpg
Apatoraptor 2016 Horseshoe Canyon Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Quill knobs preserved on its ulna confirm this species had wings Apatoraptor NT small.jpg
Apatosaurus 1877 Morrison Formation (Late Jurassic, Kimmeridgian to Tithonian)  United States
( Colorado
 New Mexico
 Oklahoma
 Utah
 Wyoming)
Had a characteristically robust skeleton compared to other diplodocids Apatosaurus louisae by durbed.jpg
Appalachiosaurus 2005 Demopolis Chalk, Donoho Creek Formation?, Tar Heel Formation? (Late Cretaceous, Campanian)  United States
( Alabama
 North Carolina?
 South Carolina?)
The most complete theropod known from the eastern side of North America Appalachiosaurus montgomeriensis.jpg
Aquilarhinus 2019 Aguja Formation (Late Cretaceous, Campanian)  United States
( Texas)
May have been a semiaquatic, coastal species that used its unusual, shovel-shaped bill to scoop up vegetation in wet sediment Aquilarhinus LM.png
Aquilops 2014 Cloverly Formation (Early Cretaceous, Albian)  United States
( Montana)
May have had a short horn protruding from its upper beak Aquilops NT small.jpg
Arkansaurus 2018 Trinity Group (Early Cretaceous, Aptian to Albian)  United States
( Arkansas)
State dinosaur of Arkansas. Its generic name was in use informally even before its formal description Arkansaurus NT.jpg
Arrhinoceratops 1925 Horseshoe Canyon Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta)
Described as lacking a nasal horn although this is an artifact of preservation Arrhinoceratops BW.jpg
Astrodon 1859 Antlers Formation?, Arundel Formation (Early Cretaceous, Albian)  United States
( Maryland
 Oklahoma?)
State dinosaur of Maryland Astrodon johnstoni.jpg
Astrophocaudia 2012 Trinity Group (Early Cretaceous, Albian)  United States
( Texas)
Known from a single partial skeleton Astrophocaudia LM.png
Atlantosaurus 1877 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Colorado)
Potentially synonymous with Apatosaurus, but a referred species may represent a separate taxon Atlantosaurus montanus.jpg
Atrociraptor 2004 Horseshoe Canyon Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
Had a short, deep snout with enlarged teeth Atrociraptor.jpg
Aublysodon 1868 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Only known from teeth Aublysodon.jpg
Augustynolophus 2014 Moreno Formation (Late Cretaceous, Maastrichtian)  United States
( California)
State dinosaur of California. Originally named as a species of Saurolophus Augustynolophus NT.jpg
Avaceratops 1986 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Lacked the fenestrae in its frill, a feature shared only with Triceratops Avaceratops dinosaur.png
Bambiraptor 2000 Two Medicine Formation (Late Cretaceous, Campanian)  United States
( Montana)
Small but well-preserved enough to display its mix of dinosaur- and bird-like features Bambiraptor reconstruction.jpg
Barosaurus 1890 Morrison Formation (Late Jurassic, Tithonian)  United States
( South Dakota
 Utah)
Similar to Diplodocus but larger and with a longer neck Barosize.svg
Bistahieversor 2010 Fruitland Formation, Kirtland Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Analysis of its braincase suggest it behaved like tyrannosaurids despite not being a member of that family Bihastieversor NT.jpg
Bisticeratops 2022 Kirtland Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Preserves bite marks from a tyrannosaurid Bisticeratops Life Reconstruction.png
Borealopelta 2017 Clearwater Formation (Early Cretaceous, Albian)  Canada
( Alberta)
So well preserved that several osteoderms, keratin, pigments, and stomach contents are preserved in the positions they would been in while alive, without flattening or shriveling Borealopelta NT.jpg
Boreonykus 2015 Wapiti Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
One of the few dromaeosaurids known from high latitudes Boreonykus LM.jpg
Brachiosaurus 1903 Morrison Formation (Late Jurassic, Kimmeridgian to Tithonian)  United States
( Colorado
 Oklahoma
 Utah
 Wyoming)
A high browser with a tall chest and elongated forelimbs Brachiosaurus NT new.jpg
Brachyceratops 1914 Two Medicine Formation (Late Cretaceous, Campanian)  United States
( Montana)
Only known from juvenile remains. One specimen has been found to represent a subadult Styracosaurus ovatus Brachyceratops BW.jpg
Brachylophosaurus 1953 Judith River Formation, Oldman Formation, Wahweap Formation? (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana
 Utah?)
Several specimens preserve extensive soft tissue remains Brachylophosaurus NT alternate.png
Bravoceratops 2013 Javelina Formation (Late Cretaceous, Campanian to Maastrichtian)  United States
( Texas)
May have had a single small horn on the top of its frill Bravoceratops NT small.jpg
Brontomerus 2011 Cedar Mountain Formation (Early Cretaceous, Aptian to Albian)  United States
( Utah)
Possessed an enlarged ilium which supported powerful leg muscles, which it may have used to kick away predators Brontomerus.jpg
Brontosaurus 1879 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Utah
 Wyoming)
Popularly associated with Apatosaurus but a 2015 study found enough differences for it to be classified as a separate genus Brontosaurus by Tom Parker.png
Caenagnathus 1940 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
One of the largest known caenagnathids Caenagnathus mandible.jpg
Camarasaurus 1877 Morrison Formation, Summerville Formation? (Late Jurassic, Kimmeridgian to Tithonian)  United States
( Colorado
 New Mexico?
 Oklahoma?
 South Dakota?
 Utah
 Wyoming)
Very common and known from multiple specimens Camarasaurs1.jpg
Camposaurus 1998 Bluewater Creek Formation (Late Triassic, Norian)  United States
( Arizona)
Potentially the oldest known neotheropod Camposaurus arizonensis.png
Camptosaurus 1885 Morrison Formation (Late Jurassic, Oxfordian to Tithonian)  United States
( Utah
 Wyoming)
May have fed on tough vegetation as evidenced by extensive wear frequently exhibited on its teeth Camptosaurus.jpg
Caseosaurus 1998 Dockum Group (Late Triassic, Norian)  United States
( Texas)
Possibly synonymous with Chindesaurus Caseosaurus ilium.jpg
Cedarosaurus 1999 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
One specimen preserves over a hundred gastroliths Cedarosaurus SW.png
Cedarpelta 2001 Cedar Mountain Formation (Late Cretaceous, Cenomanian to Turonian)  United States
( Utah)
Lacked the extensive cranial ornamentation of later ankylosaurs Cedarpelta.jpg
Cedrorestes 2007 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
Known from a partial skeleton. The specific name, C. crichtoni, is named after Michael Crichton, author of Jurassic Park Left ilium of Cedrorestes.png
Centrosaurus 1904 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Hundreds of individuals have been preserved in a single "mega-bonebed" Centrosaurus.png
Cerasinops 2007 Two Medicine Formation (Late Cretaceous, Campanian)  United States
( Montana)
Combines features of both Asian and American basal ceratopsians Cerasinops BW.jpg
Ceratops 1888 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Although only known from a few bones, this genus is the namesake of the Ceratopsia and the Ceratopsidae Ceratops.jpg
Ceratosaurus 1884 Morrison Formation (Late Jurassic, Oxfordian to Tithonian)  United States
( Colorado
 Utah
 Wyoming)
Possessed a row of osteoderms running down its back Ceratosaurus nasicornis DB.jpg
Chasmosaurus 1914 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Known from multiple remains, including various skulls Chasmosaurus BW.jpg
Chindesaurus 1995 Chinle Formation (Late Triassic, Norian)  United States
( Arizona)
May be a herrerasaur or a close relative of Tawa Chindesaurus femur.png
Chirostenotes 1924 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Originally known only from isolated body parts Volant Chirostenotes.jpg
Cionodon 1874 Denver Formation, Judith River Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta)
 United States
( Colorado)
Poorly known Cionodon arctatus.jpg
Citipes 2020 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Some specimens were found as stomach contents of Gorgosaurus Citipes elegans.jpg
Claosaurus 1890 Niobrara Formation (Late Cretaceous, Santonian to Campanian)  United States
( Kansas)
Historically conflated with other hadrosaurs Kansas sea2DB.jpg
Coahuilaceratops 2010 Cerro del Pueblo Formation (Late Cretaceous, Campanian)  Mexico
( Coahuila)
Possessed the longest brow horns of any ceratopsian Coahuilaceratops NT.jpg
Coelophysis 1889 Chinle Formation (Late Triassic, Carnian to Rhaetian)  United States
( Arizona
 New Mexico)
Known from over a thousand specimens, making it one of the more well-known early dinosaurs. Some referred species may belong to their own genera Coelophysis size.jpg
Coelurus 1879 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Wyoming)
Potentially an early member of the tyrannosauroid lineage Coelurus BW.jpg
Colepiocephale 2003 Foremost Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Originally described as a species of Stegoceras Colepiocephale updating version.JPG
Convolosaurus 2019 Twin Mountains Formation (Early Cretaceous, Aptian)  United States
( Texas)
Before its formal description, it had been informally referred to as the "Proctor Lake hypsilophodont" 3d model Convolosaurus marri.png
Coronosaurus 2012 Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Had irregular masses of small spikes on the very top of its frill Coronosaurus NT small.jpg
Corythosaurus 1914 Dinosaur Park Formation, Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Possessed a semicircular crest which may have been used for vocalization Life reconstruction of Corythosaurus casuarius.png
Crittendenceratops 2018 Fort Crittenden Formation (Late Cretaceous, Campanian)  United States
( Arizona)
The youngest known member of the Nasutoceratopsini Crittendenceratops shaded.jpg
Daemonosaurus 2011 Chinle Formation (Late Triassic, Rhaetian)  United States
( New Mexico)
Unique among early dinosaurs for possessing a short snout with long teeth Daemonosaurus chauliodus.jpg
Dakotadon 2008 Lakota Formation (Early Cretaceous, Barremian)  United States
( South Dakota)
Originally named as a species of Iguanodon Dakotadon restoration.png
Dakotaraptor 2015 Hell Creek Formation (Late Cretaceous, Maastrichtian)  United States
( South Dakota)
The holotype assemblage may represent a chimera of multiple taxa Dakotaraptor wiki.jpg
Daspletosaurus 1970 Dinosaur Park Formation, Judith River Formation, Oldman Formation, Two Medicine Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana)
At least three species are known. These have been interpreted as forming an anagenetic lineage but this hypothesis has been criticized Daspletosaurus torosus steveoc.jpg
Deinonychus 1969 Antlers Formation, Arundel Formation?, Cedar Mountain Formation?, Cloverly Formation (Early Cretaceous, Aptian to Albian)  United States
( Maryland?
 Montana
 Oklahoma
 Utah?
 Wyoming)
Its discovery helped researchers realize that dinosaurs were active, warm-blooded animals, kicking off the Dinosaur Renaissance Deinonychus ewilloughby.png
Denversaurus 1988 Lance Formation (Late Cretaceous, Maastrichtian)  United States
( South Dakota
 Wyoming)
The youngest known nodosaurid Denversaurus schlessmani scale.png
Diabloceratops 2010 Wahweap Formation (Late Cretaceous, Campanian)  United States
( Utah)
Had a distinctively short and deep skull Diabloceratops NT.jpg
Diclonius 1876 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Replaced its teeth in such a way that new teeth could be used at the same time as older ones
Dilophosaurus 1970 Kayenta Formation (Early Jurassic, Sinemurian to Pliensbachian)  United States
( Arizona)
Possessed two semicircular crests running along the length of the skull Dilophosaurus with nest.png
Dineobellator 2020 Ojo Alamo Formation (Late Cretaceous, Maastrichtian)  United States
( New Mexico)
Several features of its hands and feet may be adaptations for increased grip strength Dineobellator notohesperus NT.jpg
Diplodocus 1878 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Colorado
 Montana
 New Mexico
 Utah
 Wyoming)
Had a long, thin tail. Popularly thought to have been used like a bullwhip but it is possible that it could not handle the stress of supersonic travel Diplodocus carnegii.jpg
Diplotomodon 1868 Hornerstown Formation?/Navesink Formation? (Late Cretaceous, Maastrichtian)  United States
( New Jersey)
Has been suggested to be non-dinosaurian Diplotomodon.jpg
Dromaeosaurus 1922 Dinosaur Park Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta)
Analysis of wear on its teeth suggest it preferred tougher prey, including bone Dromaeosaurus Restoration.png
Dromiceiomimus 1972 Horseshoe Canyon Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
May be synonymous with Ornithomimus edmontonicus Dromiceiomimus 03747.JPG
Dryosaurus 1894 Morrison Formation (Late Jurassic, Kimmeridgian to Tithonian)  United States
( Colorado
 Utah
 Wyoming)
Remains of multiple growth stages have been found, including embryoes DryosaurusNV.jpg
Dryptosaurus 1877 Hornerstown Formation?/New Egypt Formation? (Late Cretaceous, Maastrichtian)  United States
( New Jersey)
Its discovery showed that theropods were bipedal animals Dryptosaurus by Durbed.jpg
Dynamoterror 2018 Menefee Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Part of the Teratophoneini, a clade of exclusively southwestern American tyrannosaurs Dynamoterror right frontal in dorsal and ventral views.png
Dyoplosaurus 1924 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
The holotype specimen preserves skin impressions Dyoplosaurus.tif
Dysganus 1876 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Four species have been named, all from isolated teeth
Dyslocosaurus 1992 Lance Formation?/Morrison Formation? (Late Jurassic, Kimmeridgian?/Late Cretaceous, Maastrichtian?)  United States
( Wyoming)
Has been suggested to have four claws on its hind limbs Dyslocosaurus polyonychius.jpg
Dystrophaeus 1877 Morrison Formation (Late Jurassic, Oxfordian)  United States
( Utah)
Inconsistent in phylogenetic placement, although undescribed remains could further clarify its relationships Pube di Dystrophaeus.jpg
Edmontonia 1928 Dinosaur Park Formation, Horseshoe Canyon Formation, Judith River Formation? (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta)
 United States
( Montana?)
Possessed forward-pointing, bifurcated spikes on its shoulders Edmontonia rugosidens.png
Edmontosaurus 1917 Frenchman Formation, Hell Creek Formation, Horseshoe Canyon Formation, Lance Formation, Prince Creek Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta
 Saskatchewan)
 United States
( Alaska
 Colorado
 Montana
 North Dakota
 South Dakota
 Wyoming)
Known from multiple well-preserved specimens, including a few "mummies". Several were originally assigned to their own genera and/or species Edmontosaurus sp. reconstruction.PNG
Einiosaurus 1994 Two Medicine Formation (Late Cretaceous, Campanian)  United States
( Montana)
Distinguished by its forward-curving nasal horn Einiosaurus BW.jpg
Eolambia 1998 Cedar Mountain Formation (Late Cretaceous, Cenomanian)  United States
( Utah)
Remains of multiple individuals are known, making up much of the skeleton Eolambia.png
Eotrachodon 2016 Mooreville Chalk (Late Cretaceous, Santonian)  United States
( Alabama)
Had a saurolophine-like skull despite its basal position Eotrachodon NT small.jpg
Eotriceratops 2007 Horseshoe Canyon Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
May have been the largest known ceratopsid Eotriceratops BW.jpg
Epichirostenotes 2011 Horseshoe Canyon Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
Its discovery allowed researchers to connect isolated caenagnathid body parts to each other Epichirostenotes.jpg
Euoplocephalus 1910 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Unusually, its palpebral bone was mobile, allowing it to be used as an eyelid Euoplocephalus BW.jpg
Falcarius 2005 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
Transitional between generalized theropods and specialized therizinosaurs Falcarius reconstruction.jpg
Ferrisaurus 2019 Tango Creek Formation (Late Cretaceous, Maastrichtian)  Canada
( British Columbia)
Its holotype was discovered close to a railway line Ferrisaurus.jpg
Foraminacephale 2016 Dinosaur Park Formation, Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Originally assigned to three different pachycephalosaurid genera Foraminacephale.png
Fosterovenator 2014 Morrison Formation (Late Jurassic, Oxfordian to Tithonian)  United States
( Wyoming)
Has been variously described as a ceratosaurid, a tetanuran, or a close relative of Elaphrosaurus Fosterovenator fíbula.jpg
Fruitadens 2010 Morrison Formation (Late Jurassic, Tithonian)  United States
( Colorado)
One of the smallest known ornithischians Fruitadens.jpg
Furcatoceratops 2023 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Preserves most of the postcranial skeleton, a rarity for ceratopsids. Remains originally identified as Avaceratops Furcatoceratops.png
Galeamopus 2015 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Colorado
 Wyoming)
One specimen is nearly complete, even preserving an associated skull Galeamopus.jpg
Gargoyleosaurus 1998 Morrison Formation (Late Jurassic, Kimmeridgian to Tithonian)  United States
( Wyoming)
Combines features of both ankylosaurids and nodosaurids Gargoyle.png
Gastonia 1998 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
Several concentrations of fossils may suggest this taxon lived in herds Gastonia burgei dinosaur.png
Geminiraptor 2010 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
The proportions of its maxilla are similar to those of Late Cretaceous troodontids Geminiraptor NT.jpg
Glishades 2010 Two Medicine Formation (Late Cretaceous, Campanian)  United States
( Montana
Described as a basal hadrosauroid but may in fact be a juvenile saurolophine hadrosaurid
Glyptodontopelta 2000 Ojo Alamo Formation (Late Cretaceous, Campanian to Maastrichtian)  United States
( New Mexico)
Originally interpreted as possessing a flat mosaic of osteoderms similar to the shields of glyptodonts Glyptodontopelta mima profile reconstruction.jpg
Gojirasaurus 1997 Dockum Group (Late Triassic, Norian)  United States
( New Mexico)
May be a chimera consisting of undiagnostic theropod bones mixed with pseudosuchian vertebrae Gojirasaurus BW.jpg
Gorgosaurus 1914 Dinosaur Park Formation, Judith River Formation?, Two Medicine Formation? (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana?)
Dozens of specimens are known Gorgosaurus 2022 Life Reconstruction.png
Gravitholus 1979 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Potentially synonymous with Stegoceras Gravitholus.png
Gremlin 2023 Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Possessed a ridge running along the top of the skull Gremlin UDL.png
Gryphoceratops 2012 Milk River Formation (Late Cretaceous, Santonian)  Canada
( Alberta)
Potentially the smallest adult ceratopsian known from North America Gryphoceratops morrisoni.png
Gryposaurus 1914 Bearpaw Formation?, Dinosaur Park Formation, Javelina Formation?, Kaiparowits Formation, Two Medicine Formation (Late Cretaceous, Santonian to Maastrichtian)  Canada
( Alberta)
 United States
( Montana
 Texas?
 Utah)
One specimen preserves impressions of a row of pyramidal scales running along its back Gryposaurus-notabilis jconway.png
Hadrosaurus 1858 Woodbury Formation (Late Cretaceous, Campanian)  United States
( New Jersey)
Its holotype was the first dinosaur skeleton to be mounted Hadrosaurus foulkii restoration.png
Hagryphus 2005 Kaiparowits Formation (Late Cretaceous, Campanian)  United States
( Utah)
Large but only known from a single hand Hagryphus2.jpg
Hanssuesia 2003 Dinosaur Park Formation, Judith River Formation, Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana)
One dome preserves several lesions Hanssuesia sternbergi.jpg
Haplocanthosaurus 1903 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Colorado
 Montana?
 Wyoming)
One of the smallest sauropods of the Morrison Formation Haplocanthosaurus.jpg
Hesperonychus 2009 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
A common component of its habitat as indicated by the great number of its remains Hesperonychus elizabethae pelvis by Nick Longrich.jpg
Hesperornithoides 2019 Morrison Formation (Late Jurassic, Oxfordian to Tithonian)  United States
( Wyoming)
Before its formal description, it had been nicknamed "Lori" Hesperornithoides.png
Hesperosaurus 2001 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Montana
 Wyoming)
Two morphotypes of plates are known, which has been interpreted as an indication of sexual dimorphism Hesperosaurus restoration.jpg
Hierosaurus 1909 Niobrara Formation (Late Cretaceous, Coniacian to Campanian)  United States
( Kansas)
Only known from a few bones, including osteoderms Hierosaurus sternbergi.jpg
Hippodraco 2010 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
Its tooth crowns were shaped like shields Hippodraco restoration.png
Hoplitosaurus 1902 Lakota Formation (Early Cretaceous, Barremian)  United States
( South Dakota)
Known from some osteoderms, including spikes, similar to those of Polacanthus Hoplitosaurus marshi.jpg
Huehuecanauhtlus 2012 Unnamed formation (Late Cretaceous, Santonian)  Mexico
( Michoacán)
The southernmost non-hadrosaurid hadrosauroid known from North America Huehuecanauhtlus tiquichensis copia.jpg
Hypacrosaurus 1913 Horseshoe Canyon Formation, Two Medicine Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta)
 United States
( Montana)
Some juveniles of this genus were originally interpreted as dwarf lambeosaurines Life reconstruction of Hypacrosaurus altispinus.png
Hypsibema 1869 Black Creek Group, Ripley Formation (Late Cretaceous, Campanian)  United States
( Missouri
 North Carolina)
Potentially one of the largest non-hadrosaurid hadrosauroids HypsibemaCrassicaudaVertNC.jpg
Hypsirhophus 1878 Morrison Formation (Late Jurassic, Tithonian)  United States
( Colorado)
Usually seen as synonymous with Stegosaurus but may be a separate genus due to differences in its vertebrae Hypsirhophus discurus.png
Iani 2023 Cedar Mountain Formation (Late Cretaceous, Cenomanian)  United States
( Utah)
It and possibly Tenontosaurus represent the only known rhabdodontomorphs from North America Iani UDL.png
Iguanacolossus 2010 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
Large and robustly built Life restoration of Iguanacolossus.jpg
Invictarx 2018 Menefee Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Only known from a few bones but can be distinguished from other genera by characters of its osteoderms Invictarx zephyri.jpg
Issi 2021 Fleming Fjord Formation (Late Triassic, Norian)  Greenland
(Sermersooq)
Originally described as an exemplar of Plateosaurus Issi saaneq.png
Jeyawati 2010 Moreno Hill Formation (Late Cretaceous, Turonian)  United States
( New Mexico)
Its postorbital bone had a rugose texture Jeyawati NT.jpg
Judiceratops 2013 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Unusually, its brow horns were teardrop-shaped in cross-section Judiceratops tigris by Nick Longrich.jpg
Kaatedocus 2012 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Wyoming)
Originally interpreted as a diplodocid although study finds it to be more likely a basal dicraeosaurid Kaatedocus skull.png
Kayentavenator 2010 Kayenta Formation (Early Jurassic, Sinemurian to Pliensbachian)  United States
( Arizona)
Described in a book published through an online print-on-demand service Kayentavenator.jpg
Koparion 1994 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Utah)
Known from a single tooth which may have come from a troodontid Koparion NT.jpg
Kosmoceratops 2010 Kaiparowits Formation (Late Cretaceous, Campanian)  United States
( Utah)
Possessed fifteen horns and horn-like structures, including eight hornlets folding down from the top of the frill Kosmoceratops NT small.jpg
Kritosaurus 1910 El Picacho Formation?, Javelina Formation?, Kirtland Formation, Ojo Alamo Formation? (Late Cretaceous, Campanian)  United States
( New Mexico
 Texas)
Had an elevated nasal bone with an enlarged nasal cavity to match Kritosaurus BW.jpg
Labocania 1974 La Bocana Roja Formation (Late Cretaceous, Campanian)  Mexico
( Baja California)
Robustly built with particularly strengthened frontals LabocaniaanomalaSkull.png
Lambeosaurus 1923 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Possessed a hollow head crest that varied in shape between species, sexes, and ages. Most familiarly, it was hatchet-shaped in adult male L. lambei Lambeosaurus2-v2.jpg
Laosaurus 1878 Morrison Formation (Late Jurassic, Oxfordian to Tithonian)  United States
( Wyoming)
Several referred specimens have been reassigned to other taxa Laosaurus celer pubis.png
Latirhinus 2012 Cerro del Pueblo Formation (Late Cretaceous, Campanian)  Mexico
( Coahuila)
As described, it represented a chimera composed of lambeosaurine and saurolophine remains; the exact holotypic bones belonged to a lambeosaurine Life reconstruction of Latirhinus uitstlani.png
Lepidus 2015 Dockum Group (Late Triassic, Norian)  United States
( Texas)
Muscle scars are preserved on the holotype bones Lepidus praecisio.jpg
Leptoceratops 1914 Hell Creek Formation, Lance Formation, Scollard Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
 United States
( Montana
 Wyoming)
Analysis of its teeth show it could chew like a mammal, an adaptation to eating tough, fibrous plants Leptoceratops BW.jpg
Leptorhynchos 2013 Aguja Formation (Late Cretaceous, Campanian to Maastrichtian)  United States
( Texas)
Had a slightly upturned mandible similar to those of oviraptorids Leptorhynchos by Nick Longrich.jpg
Lophorhothon 1960 Black Creek Formation?, Mooreville Chalk (Late Cretaceous, Campanian)  United States
( Alabama
 North Carolina?)
Although incomplete, the holotype skull preserves evidence of a crest Lophorhothon atopus.jpg
Lythronax 2013 Wahweap Formation (Late Cretaceous, Campanian)  United States
( Utah)
Already had the forward-directed orbits of derived tyrannosaurids despite its early age Lythronax UDL.png
Machairoceratops 2016 Wahweap Formation (Late Cretaceous, Campanian)  United States
( Utah)
Possessed two long, forward-pointing horns on the top of its frill Machairoceratops NT small.jpg
Magnapaulia 2012 El Gallo Formation (Late Cretaceous, Campanian)  Mexico
( Baja California)
Has been suggested to be semi-aquatic due to its tall, narrow tail Magnapaulia skeleton.jpg
Maiasaura 1979 Oldman Formation, Two Medicine Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana)
Remains of hundreds of individuals, including juveniles, eggs, and nests, have been found at a single site Maiasaura BW.jpg
Malefica 2022 Aguja Formation (Late Cretaceous, Campanian)  United States
( Texas)
Its discovery suggests a greater diversity of basal hadrosaurids than previously thought Malefica.png
Maraapunisaurus 2018 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Colorado)
Named from a single, lost vertebra of immense size Maraapunisaurus.jpg
Marshosaurus 1976 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Colorado?
 Utah)
Potentially a close relative of South American megalosauroids Marshosaurus restoration.jpg
Martharaptor 2012 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
Had not yet acquired the robust feet of derived therizinosaurs Martharaptor.tif
Medusaceratops 2010 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Possessed elongated spikes curving away from the sides of its frill Medusaceratops NT.jpg
Menefeeceratops 2021 Menefee Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
One of the oldest centrosaurines Menefeeceratops.png
Mercuriceratops 2014 Dinosaur Park Formation, Judith River Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana)
Had "wing"-like projections on its squamosal bones Mercuriceratops NT small.jpg
Microvenator 1970 Cloverly Formation (Early Cretaceous, Albian)  United States
( Montana)
Teeth from Deinonychus have been mistakenly attributed to this species Microvenator.jpg
Mierasaurus 2017 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
One of the latest-surviving turiasaurs Mierasaurus Skull.png
Moabosaurus 2017 Cedar Mountain Formation (Early Cretaceous, Aptian)  United States
( Utah)
Described as a macronarian but has since been reinterpreted as a turiasaur closely related to Mierasaurus Moabosaurus utahensis restoration.png
Monoclonius 1876 Dinosaur Park Formation, Judith River Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana)
Only known from indistinct remains of juveniles and subadults Monoclonius 07539.JPG
Montanoceratops 1951 Horseshoe Canyon Formation?, St. Mary River Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
 United States
( Montana)
Often restored with a short nasal horn although this may be a displaced cheek horn Montanoceratops BW.jpg
Moros 2019 Cedar Mountain Formation (Late Cretaceous, Cenomanian)  United States
( Utah)
The proportions of its metatarsals are similar to those of ornithomimids Moros intrepidus reconstruction.png
Mymoorapelta 1994 Morrison Formation (Late Jurassic, Kimmeridgian to Tithonian)  United States
( Colorado
 Utah)
The first ankylosaur described from the Morrison Formation Mymoorapelta maysi.png
Naashoibitosaurus 1993 Kirtland Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Like other kritosaurins, it possessed a nasal arch, but it was not as tall as that of Gryposaurus Naashoibitosaurus ostromi.png
Nanosaurus 1877 Morrison Formation (Late Jurassic, Oxfordian to Tithonian)  United States
( Colorado
 Wyoming)
Several referred specimens were originally assigned to other genera Nanosaurus.jpg
Nanuqsaurus 2014 Prince Creek Formation (Late Cretaceous, Maastrichtian)  United States
( Alaska)
Described as a dwarf tyrannosaurid although undescribed remains suggest a size comparable to Albertosaurus Nanuqsaurus hoglundi size chart.png
Nasutoceratops 2013 Kaiparowits Formation (Late Cretaceous, Campanian)  United States
( Utah)
Possessed an enlarged nasal cavity and two long, curving horns similar to those of modern cattle Nasutuceratops NT.jpg
Navajoceratops 2020 Kirtland Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Had a distinctive notch at the very top of its frill, similar to its potential ancestor Pentaceratops Navajoceratops.png
Nedcolbertia 1998 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
Known from three partial skeletons. The specific name, N. justinhofmanni, honors a six-year-old schoolboy who won a contest to have a dinosaur named after him Nedclobertia.jpg
Nevadadromeus 2022 Willow Tank Formation (Late Cretaceous, Cenomanian)  United States
( Nevada)
The first non-avian dinosaur described from Nevada Nevadadromeus reconstruction.jpg
Niobrarasaurus 1995 Niobrara Formation (Late Cretaceous, Coniacian to Campanian)  United States
( Kansas)
Originally mistakenly believed to have been aquatic Niobrarasaurus femur.jpg
Nodocephalosaurus 1999 Kirtland Formation (Late Cretaceous, Campanian to Maastrichtian)  United States
( New Mexico)
Closely related to Asian ankylosaurs
Nodosaurus 1889 Frontier Formation (Late Cretaceous, Cenomanian to Coniacian)  United States
( Wyoming)
Its armor included banded dermal plates interspersed by bony nodules Nodosaurus 500 TWA.JPG
Nothronychus 2001 Moreno Hill Formation, Tropic Shale (Late Cretaceous, Turonian)  United States
( New Mexico
 Utah)
Would have lived in the marshes and swamps along the Turonian shoreline Nothronychus mckinleyi Restoration.png
Ojoraptorsaurus 2011 Ojo Alamo Formation (Late Cretaceous, Maastrichtian)  United States
( New Mexico)
Only known from an incomplete pair of pubes Ojoraptorsaurus boerei profile reconstruction.jpg
Oohkotokia 2013 Two Medicine Formation (Late Cretaceous, Campanian)  United States
( Montana)
Potentially a synonym of Scolosaurus Oohkotokia.jpg
Ornatops 2021 Menefee Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Preserves a pair of bumps on its skull which may have anchored a crest Ornatops incantatus.png
Ornitholestes 1903 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Wyoming)
May have possessed a sickle claw similar to those of dromaeosaurids Ornitholestes reconstruction.png
Ornithomimus 1890 Denver Formation, Dinosaur Park Formation, Ferris Formation?, Horseshoe Canyon Formation, Kaiparowits Formation? (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta)
 United States
( Colorado
 Utah?
 Wyoming)
One referred specimen preserves impressions of ostrich-like feathers covering most of its body "Ornithomimus" sp. by Tom Parker.png
Orodromeus 1988 Two Medicine Formation (Late Cretaceous, Campanian)  United States
( Montana)
Eggs considered to belong to this taxon may have actually come from a troodontid Orodromeus (pencil 2013).png
Oryctodromeus 2007 Blackleaf Formation, Wayan Formation (Late Cretaceous, Cenomanian)  United States
( Idaho
 Montana)
Several specimens have been preserved in burrows Oryctodromeus.jpg
Osmakasaurus 2011 Lakota Formation (Early Cretaceous, Valanginian)  United States
( South Dakota)
Originally named as a species of Camptosaurus
Pachycephalosaurus 1943 Hell Creek Formation, Lance Formation, Scollard Formation? (Late Cretaceous, Maastrichtian)  Canada
( Alberta?)
 United States
( Montana
 South Dakota
 Wyoming)
Possessed a tall, rounded head dome surrounded by bony knobs Pachycephalosaurus Reconstruction.jpg
Pachyrhinosaurus 1950 Horseshoe Canyon Formation, Prince Creek Formation, St. Mary River Formation, Wapiti Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta)
 United States
( Alaska)
Three species have been named, each with a unique pattern of cranial ornamentation Pachyrhinosaurus BW.jpg
Palaeoscincus 1856 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Although many restorations depict it with the spikes of Edmontonia and the tail club of Ankylosaurus, this is most likely incorrect Palaeoscincus costatus.jpg
Panoplosaurus 1919 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Unlike other nodosaurs, it lacked enlarged spikes Panoplosaurus 055.JPG
Parasaurolophus 1922 Dinosaur Park Formation, Fruitland Formation, Kaiparowits Formation, Kirtland Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( New Mexico
 Utah)
Possessed a curved, hollow crest that varied in size between species Parasaurolophus walkeri.png
Paraxenisaurus 2020 Cerro del Pueblo Formation (Late Cretaceous, Campanian)  Mexico
( Coahuila)
Described as the first deinocheirid from North America Paraxenisaurus Manual Claw.jpg
Parksosaurus 1937 Horseshoe Canyon Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
Had long toes which may be an adaptation to walking on soft soils in watercourses and marshlands Parksosaurus Steveoc86.jpg
Paronychodon 1876 Hell Creek Formation, Judith River Formation, Lance Formation (Late Cretaceous, Campanian to Maastrichtian)  United States
( Montana
 North Dakota
 South Dakota
 Wyoming)
Only known from highly distinctive teeth Paronychodon.png
Pawpawsaurus 1996 Paw Paw Formation (Early Cretaceous to Late Cretaceous, Albian to Cenomanian)  United States
( Texas)
Had enlarged nasal cavities that gave it an acute sense of smell, even more powerful than that of contemporary theropods Pawpawsaurus campbelli.jpg
Pectinodon 1982 Hell Creek Formation, Lance Formation (Late Cretaceous, Maastrichtian)  United States
( Wyoming)
Had comb-like serrations on its teeth Pectinodon UDL.png
Peloroplites 2008 Cedar Mountain Formation (Late Cretaceous, Cenomanian to Turonian)  United States
( Utah)
One of the largest known nodosaurids Peloroplites price 1.jpg
Pentaceratops 1923 Fruitland Formation, Kirtland Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Its epijugal bones (the hornlets under its eyes) were relatively large Pentaceratops BW.jpg
Planicoxa 2001 Cedar Mountain Formation (Early Cretaceous, Hauterivian to Albian)  United States
( Utah)
The rear of its ilium was characteristically flat Planicoxa reconstruction raingerr.png
Platypelta 2018 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Originally assigned to Euoplocephalus but given its own genus because of several morphological differences Platypelta AMNH 5337.tiff
Platytholus 2023 Hell Creek Formation (Late Cretaceous, Maastrichtian)  United States
( Montana)
Differs from juveniles of the contemporary Pachycephalosaurus and Sphaerotholus, hence its separation as a new genus Platytholus clemensi.png
Podokesaurus 1911 Portland Formation (Early Jurassic, Hettangian to Sinemurian)  United States
( Massachusetts)
May have had a tail one and a half times longer than the rest of its skeleton Podokesaurus restoration.jpg
Polyodontosaurus 1932 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
May be identical to Latenivenatrix
Polyonax 1874 Denver Formation (Late Cretaceous, Maastrichtian)  United States
( Colorado)
Poorly known
Prenoceratops 2004 Oldman Formation, Two Medicine Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana)
The only basal ceratopsian known from a bonebed Prenoceratops BW.jpg
Priconodon 1888 Arundel Formation (Early Cretaceous, Aptian to Albian)  United States
( Maryland)
Large but only known from teeth Priconodon.jpg
Probrachylophosaurus 2015 Foremost Formation, Judith River Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana)
Shows a skull morphology transitional between crestless and crested brachylophosaurins Probrachylophosaurus restoration.jpg
Propanoplosaurus 2011 Patuxent Formation (Early Cretaceous, Aptian)  United States
( Maryland)
Only known from the imprints of a neonate skeleton Propanoplosaurus restoration.png
Prosaurolophus 1916 Dinosaur Park Formation, Two Medicine Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana)
Had a relatively large head for a hadrosaur Prosaurolophus Maximus.jpg
Protohadros 1998 Woodbine Formation (Late Cretaceous, Cenomanian)  United States
( Texas)
Possessed a downturned jaw which may be an adaptation to grazing on low-growing plants
Pteropelyx 1889 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Potentially synonymous with Corythosaurus, although this cannot be confirmed due to a lack of cranial remains
Rativates 2016 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Originally described as a specimen of Struthiomimus Rativates.png
Regaliceratops 2015 St. Mary River Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
Possessed a series of large, pentagonal plates lining its frill Regaliceratops peterhewsi.jpg
Richardoestesia 1990 Aguja Formation, Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Texas)
Teeth assigned to this genus have been recovered all around the world, in deposits spanning millions of years of time, although they may not represent a single taxon Ojo Alamo cf. Richardoestesia sp profile reconstruction.jpg
Rugocaudia 2012 Cloverly Formation (Early Cretaceous, Aptian to Albian)  United States
( Montana)
Some of this genus' remains include several caudal vertebrae Rugocaudia.png
Sarahsaurus 2011 Kayenta Formation (Early Jurassic, Sinemurian to Pliensbachian)  United States
( Arizona)
Possessed strong hands which may indicate a feeding specialization Sarahsaurus restoration.PNG
Saurolophus 1912 Horseshoe Canyon Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta)
Had a short, solid crest that pointed directly upwards. A larger, more well-known species has been found in Mongolia Saurolophus scalation.png
Sauropelta 1970 Cedar Mountain Formation?, Cloverly Formation (Early Cretaceous, Albian)  United States
( Montana
 Utah?
 Wyoming)
Its tail had at least forty vertebrae, making up half of its total body length Sauropelta jconway.png
Saurophaganax 1995 Morrison Formation (Late Jurassic, Kimmeridgian to Tithonian)  United States
( New Mexico?
 Oklahoma)
Potentially an extremely large specimen of Allosaurus Saurophaganax restoration 2019 by Mario Lanzas.jpg
Sauroposeidon 2000 Antlers Formation, Glen Rose Formation (Early Cretaceous, Aptian to Albian)  United States
( Oklahoma
 Texas
 Wyoming)
Could raise its head up to 18 metres (59 ft) in the air, the height of a six-storey building Sauroposeidon proteles.jpg
Saurornitholestes 1978 Coachman Formation, Dinosaur Park Formation, Donoho Creek Formation, Kirtland Formation, Mooreville Chalk, Oldman Formation, Tar Heel Formation, Two Medicine Formation (Late Cretaceous, Campanian)  Canada
( Alberta
( United States
( Alabama
 Montana
 New Mexico
 North Carolina
 South Carolina)
Its second premaxillary teeth could be adapted to preening feathers Saurornitholestes digging Burrows wahweap.jpg
Scolosaurus 1928 Dinosaur Park Formation, Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Once widely believed to be synonymous with other Campanian ankylosaurids Scolosaurus SW.png
Scutellosaurus 1981 Kayenta Formation (Early Jurassic, Sinemurian)  United States
( Arizona)
Had hundreds of osteoderms arranged in rows along its back and tail Scutellosaurus.jpg
Segisaurus 1936 Navajo Sandstone (Early Jurassic, Pliensbachian to Toarcian)  United States
( Arizona)
Preserves evidence of a wishbone similar to that of modern birds Segisaurus.jpg
Seitaad 2010 Navajo Sandstone (Early Jurassic, Pliensbachian)  United States
( Utah)
The holotype may have died when a sand dune collapsed on it Seitaad NT.jpg
Siats 2013 Cedar Mountain Formation (Late Cretaceous, Cenomanian)  United States
( Utah)
Large but inconsistent in phylogenetic placement Siats reconstruction.png
Sierraceratops 2022 Hall Lake Formation (Late Cretaceous, Campanian to Maastrichtian)  United States
( New Mexico)
May be part of a unique clade of ceratopsians only known from southern Laramidia Sierraceratops.jpg
Silvisaurus 1960 Dakota Formation (Early Cretaceous to Late Cretaceous, Albian to Cenomanian)  United States
( Kansas)
Hypothesized to live in a forested habitat Silvisaurus.jpg
Smitanosaurus 2020 Morrison Formation (Late Jurassic, Oxfordian to Tithonian)  United States
( Colorado)
Only known from a partial skull and some vertebrae Smitanosaurus agilis skull and neck.jpg
Sonorasaurus 1998 Turney Ranch Formation (Early Cretaceous to Late Cretaceous, Albian to Cenomanian)  United States
( Arizona)
State dinosaur of Arizona Sonorasaurus thompsoni.jpg
Sphaerotholus 2002 Dinosaur Park Formation, Frenchman Formation, Hell Creek Formation, Horseshoe Canyon Formation, Kirtland Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta
 Saskatchewan)
 United States
( Montana
 New Mexico)
Five species have been named, all known from skull elements. Lived in a broad range Sphaerotholus.jpg
Spiclypeus 2016 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Has been described as "boldly audacious" Spiclypeus NT small.jpg
Spinops 2011 Dinosaur Park Formation?/Oldman Formation? (Late Cretaceous, Campanian)  Canada
( Alberta)
Described almost a century after its remains were collected Spinops NT.jpg
Stegoceras 1902 Dinosaur Park Formation, Fruitland Formation?, Kirtland Formation?, Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( New Mexico?)
May have been an indiscriminate bulk-feeder due to the shape of its snout Stegoceras validum.jpg
Stegopelta 1905 Frontier Formation (Early Cretaceous to Late Cretaceous, Albian to Cenomanian)  United States
( Wyoming)
May have possessed a sacral shield similar to other nodosaurs Stegopelta pelvic armor.jpg
Stegosaurus 1877 Morrison Formation (Late Jurassic, Kimmeridgian to Tithonian)  United States
( Colorado
 Wyoming)
Had a single alternating row of large, kite-shaped plates Stegosaurus stenops Life Reconstruction.png
Stellasaurus 2020 Two Medicine Formation (Late Cretaceous, Campanian)  United States
( Montana)
Possessed an enlarged, thickened nasal horn Rubeosaurus nasals.jpg
Stenonychosaurus 1932 Dinosaur Park Formation, Two Medicine Formation? (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana?)
Its brain-to-body mass ratio is one of the highest of any non-avian dinosaur's Life reconstruction of Stenonychosaurus.png
Stephanosaurus 1914 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Poorly known Trachodon (Pteropelyx) marginatus humerus and skin.png
Stokesosaurus 1974 Morrison Formation (Late Jurassic, Kimmeridgian to Tithonian)  United States
( South Dakota?
 Utah)
Only known from a few remains but they are enough to tell that it was a tyrannosauroid Stokesosaurus by Tom Parker.png
Struthiomimus 1917 Horseshoe Canyon Formation?, Lance Formation?, Oldman Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta)
 United States
( Wyoming?)
Known from many specimens, indicating it was a common animal Struthiomimus BW.jpg
Styracosaurus 1913 Dinosaur Park Formation, Two Medicine Formation? (Late Cretaceous, Campanian)  Canada
( Alberta)
 United States
( Montana)?
Possessed several long horns jutting out from the top of its frill, the patterns of which could have varied between individuals Styracosaurus BW.jpg
Supersaurus 1985 Morrison Formation (Late Jurassic, Tithonian)  United States
( Colorado
 Wyoming)
Several remains were originally believed to represent their own genera Supersaurus dinosaur.png
Suskityrannus 2019 Moreno Hill Formation (Late Cretaceous, Turonian)  United States
( New Mexico)
Small yet already possessed several features of large, derived tyrannosaurids, including an arctometatarsus Suskityrannus life reconstruction.png
Suuwassea 2004 Morrison Formation (Late Jurassic, Oxfordian to Tithonian)  United States
( Montana)
Shares features with both diplodocids and dicraeosaurids, but is more likely a member of the latter group Suuwassea cervicals.jpg
Talos 2011 Kaiparowits Formation (Late Cretaceous, Campanian)  United States
( Utah)
The holotype specimen preserves a pathology on its sickle claw Talos sampsoni.jpg
Tanycolagreus 2005 Morrison Formation (Late Jurassic, Oxfordian to Tithonian)  United States
( Colorado
 Utah
 Wyoming)
Had a long, blunt snout Tanycolagreus reconstruction.png
Tatankacephalus 2009 Cloverly Formation (Early Cretaceous, Aptian to Albian)  United States
( Montana)
Retained premaxillary teeth in its upper jaws, a basal trait
Tawa 2009 Chinle Formation (Late Triassic, Norian)  United States
( New Mexico)
Well-preserved but inconsistent in phylogenetic placement Tawa hallae Martz.jpg
Tenontosaurus 1970 Antlers Formation, Arundel Formation, Cedar Mountain Formation, Cloverly Formation, Paluxy Formation, Twin Mountains Formation, Wayan Formation (Early Cretaceous, Aptian to Albian)  United States
( Idaho
 Maryland
 Montana
 Oklahoma
 Texas
 Utah)
Remains of this genus are often found associated with skeletons of Deinonychus Tenontosaurus BW.jpg
Teratophoneus 2011 Kaiparowits Formation (Late Cretaceous, Campanian)  United States
( Utah)
Its snout was shorter and deeper than those of other tyrannosaurids Teratophoneus2 NT.jpg
Terminocavus 2020 Kirtland Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Had a teardrop-shaped hole on the top of its frill which was almost closed off by a pair of epoccipitals Terminocavus.jpg
Texacephale 2010 Aguja Formation (Late Cretaceous, Campanian)  United States
( Texas)
Possessed a series of vertical flanges on its dome which may have functioned as "gears" that interlocked when head-butting Texacephale langstoni skull dome by Nick Longrich.png
Texasetes 1995 Paw Paw Formation (Early Cretaceous, Albian)  United States
( Texas)
Potentially synonymous with Pawpawsaurus NMNH-USNM337987 1.jpg
Thanatotheristes 2020 Foremost Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
A close relative of Daspletosaurus Thanatotheristes.jpg
Theiophytalia 2006 Purgatoire Formation (Early Cretaceous, Aptian to Albian)  United States
( Colorado)
Only known from a skull originally referred to Camptosaurus TheiophytaliaType.jpg
Thescelosaurus 1913 Frenchman Formation, Hell Creek Formation, Lance Formation, Laramie Formation, Scollard Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta
 Saskatchewan)
 United States
( Colorado
 Montana
 North Dakota
 South Dakota
 Wyoming)
One specimen was originally considered to have preserved its heart, although later this was found to be a mineral concretion Thescelosaurus filamented.jpg
Thespesius 1856 Lance Formation (Late Cretaceous, Maastrichtian)  United States
( South Dakota)
Once suggested to be a possible Miocene mammal Thespesius occidentalis.jpg
Tichosteus 1877 Morrison Formation (Late Jurassic, Kimmeridgian)  United States
( Colorado)
Two species have been named, both from isolated vertebrae Tichosteus lucasanus.jpg
Titanoceratops 2011 Fruitland Formation?/Kirtland Formation? (Late Cretaceous, Campanian)  United States
( New Mexico)
Potentially a large, old specimen of Pentaceratops Titanoceratops ouranos life restoration.jpg
Tlatolophus 2021 Cerro del Pueblo Formation (Late Cretaceous, Campanian)  Mexico
( Coahuila)
Possessed a short, broad crest resembling an inverted comma Tlatolophus.png
Torosaurus 1891 Frenchman Formation, Hell Creek Formation, Lance Formation, Scollard Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta
 Saskatchewan)
 United States
( Colorado?
 Montana?
 New Mexico?
 North Dakota?
 South Dakota
 Texas?
 Utah?
 Wyoming)
Once believed to be potentially synonymous with Triceratops Torosaurus life restoration.png
Torvosaurus 1979 Morrison Formation (Middle Jurassic to Late Jurassic, Callovian to Tithonian)  United States
( Colorado
 Wyoming)
Had short but powerfully built arms. Several species, many of them unnamed, have been found in Europe, South America, and possibly Africa Torvosaurus tanneri Reconstruction.png
Tototlmimus 2016 Packard Formation (Late Cretaceous, Campanian)  Mexico
( Sonora)
The southernmost ornithomimid known from North America
Trachodon 1856 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Several remains assigned to this genus actually belong to other taxa, most notably Edmontosaurus Trachodon mirabilis.jpg
Triceratops 1889 Denver Formation, Evanston Formation, Hell Creek Formation, Lance Formation, Laramie Formation, Scollard Formation (Late Cretaceous, Maastrichtian)  Canada
( Alberta
 Saskatchewan?)
 United States
( Colorado
 Montana
 South Dakota
 Wyoming)
A common ceratopsid with long brow horns and a short nasal horn Triceratops by Tom Patker.png
Trierarchuncus 2020 Hell Creek Formation (Late Cretaceous, Maastrichtian)  United States
( Montana)
Known from remains of different sizes which depict how the claws of alvarezsaurids grew more hooked as they aged Trierarchuncus prairiensis.png
Troodon 1856 Judith River Formation, Two Medicine Formation? (Late Cretaceous, Campanian)  United States
( Montana)
Only known from teeth. Most referred skeletal remains cannot be confidently assigned to this genus Troodon (cropped).jpg
Tyrannosaurus 1905 Frenchman Formation, Hall Lake Formation, Hell Creek Formation, Lance Formation, Willow Creek Formation (Late Cretaceous, Campanian to Maastrichtian)  Canada
( Alberta
 Saskatchewan)
 United States
( Colorado
 Montana
 New Mexico
 South Dakota
 Wyoming)
The last, largest, and most well-known tyrannosaurid Tyrannosaurus-rex-Profile-steveoc86.png
Unescoceratops 2012 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Had the roundest teeth of any known leptoceratopsid
Utahceratops 2010 Kaiparowits Formation (Late Cretaceous, Campanian)  United States
( Utah)
Almost the entire skeleton and skull is known Utahceratops gettyi.jpg
Utahraptor 1993 Cedar Mountain Formation (Early Cretaceous, Valanginian to Hauterivian)  United States
( Utah)
Very large and powerfully built Utahraptor Restoration.png
Uteodon 2011 Morrison Formation (Late Jurassic, Tithonian)  United States
( Utah)
May be a species of Camptosaurus, with a referred braincase being from Dryosaurus Uteodon reconstruction raingerr.png
Vagaceratops 2010 Dinosaur Park Formation (Late Cretaceous, Campanian)  Canada
( Alberta
Possessed a row of fused epoccipitals folding over the top of the frill Vagaceratops NT.jpg
Velafrons 2007 Cerro del Pueblo Formation (Late Cretaceous, Campanian)  Mexico
( Coahuila)
May have had elongated neural spines similar to those of Hypacrosaurus altispinus Life reconstruction of Velafrons coahuilensis.png
Venenosaurus 2001 Cedar Mountain Formation (Early Cretaceous, Aptian to Albian)  United States
( Utah)
Its skeleton has traits of both titanosaurs and more basal macronarians
Wendiceratops 2015 Oldman Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Had three pairs of enlarged, curved epiparietals at the very top of its frill Wendiceratops restoration.PNG
Xenoceratops 2012 Foremost Formation (Late Cretaceous, Campanian)  Canada
( Alberta)
Possessed two long spines at the top of its frill with smaller knobs at their bases Xenoceratops NT small.jpg
Yehuecauhceratops 2017 Aguja Formation (Late Cretaceous, Campanian)  Mexico
( Coahuila)
One of the smallest known ceratopsids Yehuecauhceratops.jpg
Yurgovuchia 2012 Cedar Mountain Formation (Early Cretaceous, Valanginian)  United States
( Utah)
May have had a flexible tail due to the structure of its caudal vertebrae Yurgovuchia.jpg
Zapsalis 1876 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Some teeth referred to this genus actually belong to Saurornitholestes Zapsalis.png
Zephyrosaurus 1980 Cloverly Formation (Early Cretaceous, Aptian to Albian)  United States
( Montana)
Currently only known from fragmentary remains but several undescribed specimens exist Zephyrosaurus in Copenhagen.jpg
Ziapelta 2014 Kirtland Formation (Late Cretaceous, Campanian)  United States
( New Mexico)
Many specimens are known, most from the front part of the animal Ziapelta.png
Zuniceratops 1998 Moreno Hill Formation (Late Cretaceous, Turonian)  United States
( New Mexico)
Carried a pair of brow horns despite not being a member of the Ceratopsidae Zuniceratops BW.jpg
Zuul 2017 Judith River Formation (Late Cretaceous, Campanian)  United States
( Montana)
Preserves several osteoderms, keratin, and skin remains Zuul.jpg

Invalid and potentially valid genera

  • Agathaumas sylvestris: Most well known from a painting by Charles Knight. It may have been a synonym of Triceratops, but without cranial remains, this cannot be confirmed.
  • Alcovasaurus longispinus: Although originally named as a species of Stegosaurus, it may actually be a species of the otherwise European Miragaia.
  • Antrodemus valens: May represent the same animal as Allosaurus; if so, the name Antrodemus would have priority. However, because it is based on undiagnostic remains of uncertain provenance, this cannot be confirmed.
  • Apatodon mirus: Its holotype was originally believed to be the jawbone of a Mesozoic pig, but has been reinterpreted as a dinosaur vertebra. What type of dinosaur it belonged to is unknown, but there have been suggestions that it was from Allosaurus.
  • "Beelemodon": Known only from two teeth found in Wyoming. They share features of compsognathids, dromaeosaurids, and basal oviraptorosaurs.
  • "Capitalsaurus": The official dinosaur of the District of Columbia. It is known from a single vertebra discovered at the intersection of First and F Streets S.E., which is now appropriately named "Capitalsaurus Court".
  • Cathetosaurus lewisi: Usually seen as a species of Camarasaurus, but an unpublished study argues that it might be a distinct genus.
  • Claorhynchus trihedrus: An indeterminate cerapod that may be either a hadrosaurid or a ceratopsid, in which case it may be a synonym of Triceratops.
  • "Coelosaurus" antiquus: The generic name is said to be preoccupied, but its namesake remains obscure.
  • "Comanchesaurus kuesi": Only named in a dissertation. It has been described as a possible indeterminate saurischian.
  • Deinodon horridus: Only known from teeth. Several referred teeth have since been found to belong to already known species, and the holotype could itself belong to Gorgosaurus.
  • Dracorex hogwartsia: Described as a small, flat-headed pachycephalosaur. However, it is likely that it is just a juvenile Pachycephalosaurus.
  • Drinker nisti: May be a synonym of Nanosaurus.
  • Epanterias amplexus: Possibly a large specimen of Allosaurus, but it may be a different taxon due to its younger age.
  • Latenivenatrix mcmasterae: The largest known troodontid. It is sometimes suggested to be synonymous with Stenonychosaurus, which its remains were originally assigned to.
  • "Magulodon muirkirkensis": Only known from a single tooth that may belong to either an ornithopod or a basal ceratopsian.
  • "Microcephale": Said to be an extremely small pachycephalosaur, with skull caps only 5 centimetres (2.0 in) long.
  • Mojoceratops perifania: May be a species of specimen of Chasmosaurus.
  • Nanotyrannus lancensis: Described as a small adult tyrannosaur, although it is more likely to be a juvenile Tyrannosaurus rex.
  • Nedoceratops hatcheri: Due to its lack of a nasal horn, it has been named "Diceratops" (which is preoccupied by an insect) and Diceratus. However, it may simply be an unusual specimen of Triceratops.
  • Ojoceratops fowleri: May be ancestral to Triceratops or a synonym of Eotriceratops.
  • "Orcomimus": Potentially referrable to any of the ornithomimosaur taxa known from the Hell Creek Formation.
  • Othnielia rex: Only known from an undiagnostic femur, but it may have belonged to Nanosaurus anyway.
  • Othnielosaurus consors: Most likely a synonym of Nanosaurus.
  • Palaeopteryx thomsoni: Known from a few very small bones which could belong to either a bird or a small bird-like dinosaur.
  • Protoavis texensis: Described as a Triassic bird but is more likely a chimera consisting of elements from various unrelated tetrapods.
  • Rhinorex condrupus: Phylogenetic analysis shows that it may fall within Gryposaurus, and thus be a junior synonym of that genus.
  • Rubeosaurus ovatus: Likely a species of Styracosaurus, or even simply an unusual specimen of S. albertensis.
  • Stygimoloch spinifer: Had a short skull dome with long horns jutting out from behind it. It is usually thought to be a subadult Pachycephalosaurus, but has been noted to be stratigraphically younger.
  • Tatankaceratops sacrisonorum: Noted to possess a strange mix of features of both juvenile and adult Triceratops. It may be a dwarf specimen of that genus or an individual that stopped growing prematurely.

Timeline

This is a timeline of selected dinosaurs from the list above. Time is measured in Ma, megaannum, along the x-axis.

Mesozoic Triassic Jurassic Cretaceous Leptoceratops Edmontosaurus annectens Thescelosaurus Tyrannosaurus Ankylosaurus Triceratops Torosaurus Eotriceratops Saurolophus Pachycephalosaurus Alamosaurus Montanoceratops Albertosaurus Anchiceratops Velafrons Edmontosaurus regalis Kritosaurus Ziapelta Brachyceratops Hypacrosaurus Struthiomimus Pentaceratops Styracosaurus Parasaurolophus Ornithomimus Edmontonia Monoclonius Lambeosaurus Corythosaurus Centrosaurus Gorgosaurus Troodon Stegoceras Brachylophosaurus Gryposaurus Niobrarasaurus Zuniceratops Sauroposeidon Tenontosaurus Deinonychus Acrocanthosaurus Utahraptor Yurgovuchia Falcarius Ornitholestes Brachiosaurus Saurophaganax Apatosaurus Barosaurus Torvosaurus Ceratosaurus Diplodocus Haplocanthosaurus Stegosaurus Allosaurus Dryosaurus Camarasaurus Brontosaurus Camptosaurus Scutellosaurus Megapnosaurus Coelophysis Mesozoic Triassic Jurassic Cretaceous

See also

  • List of Appalachian dinosaurs - for dinosaurs specifically known from the former landmass of Appalachia (where much of eastern North America is now)
  • List of North American birds
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