Hadrosaurus is a genus of hadrosaurid ornithopod dinosaurs that lived in North America during the Late Cretaceous Period in what is now the Woodbury Formation about 80 million to 78 million years ago. The holotype specimen was found in fluvial marine sedimentation, meaning that the corpse of the animal was transported by a river and washed out to sea.
Hadrosaurids, or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod family, which includes genera such as Edmontosaurus and Parasaurolophus, was a common group of herbivores during the Late Cretaceous Period. Hadrosaurids are descendants of the Upper Jurassic/Lower Cretaceous iguanodontian dinosaurs and had a similar body layout. Hadrosaurs were among the most dominant herbivores during the Late Cretaceous in Asia and North America, and during the close of the Cretaceous several lineages dispersed into Europe, Africa, South America and Antarctica.
Claosaurus is a genus of hadrosauroid dinosaur that lived during the Late Cretaceous Period (Santonian-Campanian).
Shantungosaurus is a genus of very large saurolophine hadrosaurid dinosaur found in the Late Cretaceous Wangshi Group of the Shandong Peninsula in China, containing a single species, Shantungosaurus giganteus. The stratigraphic interval of Shantungosaurus ranges from the top of the Xingezhuang Formation to the middle of the Hongtuya Formation, middle to late Campanian in age. Shantungosaurus is so far the largest hadrosauroid taxon in the world: the greatest length of its femur is about 1.7 metres (5.6 ft), and the greatest length of its humerus is about 0.97 metres (3.2 ft).
Gryposaurus was a genus of duckbilled dinosaur that lived about 80 to 75 million years ago, in the Late Cretaceous of North America. Named species of Gryposaurus are known from the Dinosaur Park Formation in Alberta, Canada, and two formations in the United States: the Lower Two Medicine Formation in Montana and the Kaiparowits Formation of Utah. A possible additional species from the Javelina Formation in Texas may extend the temporal range of the genus to 66 million years ago.
Kritosaurus is an incompletely known genus of hadrosaurid (duck-billed) dinosaur. It lived about 74.5-66 million years ago, in the Late Cretaceous of North America. The name means "separated lizard", but is often mistranslated as "noble lizard" in reference to the presumed "Roman nose".
Lophorhothon is a genus of hadrosauroid dinosaur from the Late Cretaceous, the first genus of dinosaur discovered in Alabama, in the United States.
Secernosaurus is a genus of herbivorous dinosaur. Secernosaurus was a hadrosaur, a "duck-billed" dinosaur which lived during the Late Cretaceous. Its fossils have been found in the Lago Colhué Huapi and Los Alamitos Formations of Argentina.
Pararhabdodon is a genus of tsintaosaurin hadrosaurid dinosaur, from the Maastrichtian-age Upper Cretaceous Tremp Group of Spain. The first remains were discovered from the Sant Romà d’Abella fossil locality and assigned to the genus Rhabdodon, and later named as the distinct species Pararhabdodon isonensis in 1993. Known material includes assorted postcranial remains, mostly vertebrae, as well as maxillae from the skull. Specimens from other sites, including remains from France, a maxilla previously considered the distinct taxon Koutalisaurus kohlerorum, an additional maxilla from another locality, the material assigned to the genera Blasisaurus and Arenysaurus, and the extensive Basturs Poble bonebed have been considered at different times to belong to the species, but all of these assignments have more recently been questioned. It was one of the last non-avian dinosaurs known from the fossil record that went extinct during the Cretaceous-Paleogene extinction event.
Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and all dinosaurs more closely related to them than to Iguanodon. Their remains have been recovered in Asia, Europe and Africa. Many primitive hadrosauroids, such as the Asian Probactrosaurus and Altirhinus, have traditionally been included in a paraphyletic "Iguanodontidae". With cladistic analysis, the traditional Iguanodontidae has been largely disbanded, and probably includes only Iguanodon and perhaps its closest relatives.
Penelopognathus is a genus of dinosaur which lived during the Early Cretaceous. It was an iguanodont ancestral to hadrosaurids, which also contributes to the hypothesis that hadrosauroids originated in Asia. Fossils have been found in the Bayin-Gobi Formation in what is now China. The type species, Penelopognathus weishampeli, named after David Weishampel, was described by Godefroit, Li, and Shang in 2005, based on fragmentary jaw fossils.
Lambeosaurinae is a group of crested hadrosaurid dinosaurs.
Saurolophinae is a subfamily of hadrosaurid dinosaurs. It has since the mid-20th century generally been called the Hadrosaurinae, a group of largely non-crested hadrosaurs related to the crested sub-family Lambeosaurinae. However, the name Hadrosaurinae is based on the genus Hadrosaurus which was found in more recent studies to be more primitive than either lambeosaurines or other traditional "hadrosaurines", like Edmontosaurus and Saurolophus. As a result of this, the name Hadrosaurinae was dropped or restricted to Hadrosaurus alone, and the subfamily comprising the traditional "hadrosaurines" was renamed the Saurolophinae. Recent phylogenetic work by Hai Xing indicates that Hadrosaurus is placed within the monophyletic group containing all non-lambeosaurine hadrosaurids. Under this view, the traditional Hadrosaurinae is resurrected, with the Hadrosauridae being divided into two clades: Hadrosaurinae and Lambeosaurinae.
The Mooreville Chalk is a geological formation in North America, within the U.S. states of Alabama and Mississippi, which were part of the subcontinent of Appalachia. The strata date back to the early Santonian to the early Campanian stage of the Late Cretaceous. The chalk was formed by pelagic sediments deposited along the eastern edge of the Mississippi embayment. It is a unit of the Selma Group and consists of the upper Arcola Limestone Member and an unnamed lower member. Dinosaur, mosasaur, and primitive bird remains are among the fossils that have been recovered from the Mooreville Chalk Formation.
During most of the Late Cretaceous the eastern half of North America formed Appalachia, an island land mass separated from Laramidia to the west by the Western Interior Seaway. This seaway had split North America into two massive landmasses due to a multitude of factors such as tectonism and sea-level fluctuations for nearly 40 million years. The seaway eventually expanded, divided across the Dakotas, and by the end of the Cretaceous, it retreated towards the Gulf of Mexico and the Hudson Bay. This left the island masses joined in the continent of North America as the Rocky Mountains rose. From the Cenomanian to the end of the Campanian ages of the Late Cretaceous, Appalachia was separated from the rest of North America. As the Western Interior Seaway retreated in the Maastrichtian, Laramidia and Appalachia eventually connected. Because of this, its fauna was isolated, and developed very differently from the tyrannosaur, ceratopsian, hadrosaurid, pachycephalosaur and ankylosaurid dominated fauna of the western part of North America, known as "Laramidia".
Magnapaulia is a genus of herbivorous lambeosaurine hadrosaurid dinosaurs known from the Latest Cretaceous Baja California, of northwestern Mexico. It contains a single species, Magnapaulia laticaudus. Magnapaulia was first described in 1981 as a possible species of Lambeosaurus by William J. Morris, and was given its own genus in 2012 by Prieto-Márquez and colleagues.
Tsintaosaurini is a tribe of basal lambeosaurine hadrosaurs native to Eurasia. It currently contains only Tsintaosaurus and Pararhabdodon . Koutalisaurus, also known from late Cretaceous Spain and formerly referred to Pararhabdodon, may also be a tsintaosaurin because of its association with the latter genus; some recent work also suggests it may indeed be referrable to Pararhabdodon.
Augustynolophus is an extinct genus of herbivorous saurolophine hadrosaur dinosaur which was discovered in the Moreno Formation in California, dating to the late Maastrichtian age, making it one of the last dinosaurs known from the fossil record before the Cretaceous–Paleogene extinction event.
This timeline of hadrosaur research is a chronological listing of events in the history of paleontology focused on the hadrosauroids, a group of herbivorous ornithopod dinosaurs popularly known as the duck-billed dinosaurs. Scientific research on hadrosaurs began in the 1850s, when Joseph Leidy described the genera Thespesius and Trachodon based on scrappy fossils discovered in the western United States. Just two years later he published a description of the much better-preserved remains of an animal from New Jersey that he named Hadrosaurus.
