Ornithopoda

Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (). They represent one of the most successful groups of herbivorous dinosaurs during the Cretaceous. The most primitive members of the group were bipedal and relatively small-sized, while advanced members of the subgroup Iguanodontia became quadrupedal and developed large body size. Their major evolutionary advantage was the progressive development of a chewing apparatus that became the most sophisticated ever developed by a non-avian dinosaur, rivaling that of modern mammals such as the domestic cow. They reached their a

Hypsilophodon (; meaning "high-crested tooth") is a neornithischian dinosaur genus from the Early Cretaceous period of England. It has traditionally been considered an early member of the group Ornithopoda, but recent research has put this into question.

Dryosaurus ( , meaning 'tree lizard', Greek '''' () meaning 'tree, oak' and () meaning 'lizard' (the name reflects the forested habitat, not a vague oak-leaf shape of its cheek teeth as is sometimes assumed)) is an extinct genus of herbivorous ornithopod dinosaur that lived in the Late Jurassic period. It was an iguanodont (formerly classified as a hypsilophodont). Fossils have been found in the western United States and were first discovered in the late 19th century. Valdosaurus canaliculatus and Dysalotosaurus lettowvorbecki were both formerly considered to represent species of Dryosaurus.

Hypsilophodontidae (or Hypsilophodontia) is a traditionally used family of ornithopod dinosaurs, generally considered invalid today. It historically included many small bodied bipedal neornithischian taxa from around the world, and spanning from the Middle Jurassic until the Late Cretaceous. This inclusive status was supported by some phylogenetic analyses from the 1990s and mid 2000s, although there have also been many finding that the family is an unnatural grouping which should only include the type genus, Hypsilophodon, with the other genera being within clades like Thescelosauridae and El

Draconyx (meaning "dragon claw") is a genus of ornithopod dinosaur from the Late Jurassic of what is now Portugal. It was found in the Lourinhã Formation in 1991, and described by Octávio Mateus and Miguel Telles Antunes in 2001.

Valdosaurus ("Weald lizard") is a genus of bipedal herbivorous dryosaurid dinosaur known from the Early Cretaceous of the Isle of Wight and elsewhere in England. Originally its remains were believed to belong to Hypsilophodon. In 1889, Richard Lydekker assigned them to Camptosaurus, alongside a partial lower jaw, and applied the name Camptosaurus valdensis. In the 1970s, Peter Galton reassigned these remains to a new species of Dryosaurus, then to an entirely new genus and species, that being Valdosaurus proper. The type and only species of Valdosaurus, named by Galton, is V. canaliculatus.

Callovosaurus (meaning "Callovian lizard") is a genus of iguanodontian dinosaur known from most of a left thigh bone discovered in Middle Jurassic-age rocks of England. At times, it has been considered dubious or a valid genus of basal iguanodontian, perhaps a dryosaurid.

Gideonmantellia is an extinct genus of basal ornithopod dinosaur known from the Early Cretaceous (Barremian stage) Camarillas Formation of Galve, Province of Teruel, Spain. It contains a single species, Gideonmantellia amosanjuanae.

Kangnasaurus (meaning "Farm Kangnas lizard") is a genus of elasmarian ornithopod dinosaur found in Late Cretaceous rocks of South Africa. It is known from a tooth and possibly some postcranial remains dating between the middle-Campanian to Maastrichtian Kalahari Deposits Formation.

Burianosaurus is an extinct genus of ornithopod dinosaur that lived during the Cenomanian stage of the Late Cretaceous period in what is now the Czech Republic, being the first validly named dinosaur from that country. The type species, B. augustai, was named in 2017; the genus name honours the Czech palaeoartist Zdeněk Burian, and the species name honours the Czech palaeontologist Josef Augusta. The holotype specimen is a femur discovered in sediments belonging to the Peruc-Korycany Formation in 2003, which was described as possibly belonging to an iguanodont in 2005.

Haolong () is an extinct genus of hadrosauroid ornithopod dinosaur known from the Early Cretaceous (Barremian age) Yixian Formation of Liaoning, China. The genus contains a single species, Haolong dongi, known from a nearly complete, articulated skeleton with preserved integumentary structures.

Tichosteus (meaning "walled bone") is a genus of herbivorous dinosaur from the Late Jurassic. It is known only from vertebrae recovered from Kimmeridgian rocks in the Morrison Formation, Colorado.

Syngonosaurus is an extinct genus of ornithopod dinosaur from the Early Cretaceous. It was an iguanodontian discovered in the Cambridge Greensand of England and was first described in 1879. The type species, S. macrocercus, was described by British paleontologist Harry Seeley in 1879 and it was later synonymised with Acanthopholis, but the genus was reinstated in a 2020 study, when Syngonosaurus and Eucercosaurus were reinterpreted as basal iguanodontians.

Cumnoria is a genus of basal iguanodontian dinosaur that lived during the Late Jurassic period (Kimmeridgian age) in what is now Oxfordshire, United Kingdom.

Eucercosaurus (meaning "good-tailed lizard") is the name given to a genus of ornithopod dinosaur from the Albian stage of the Early Cretaceous. It was an ornithopod discovered in the Cambridge Greensand of England and is known from 19 centra, 3 sacrals, 4 dorsals and 12 caudals, and a neural arch found near Trumpington, Cambridgeshire. The type species, E. tanyspondylus, was described by British paleontologist Harry Seeley in 1879.

Loncosaurus (meaning uncertain; either Araucanian "chief" or Greek "lance" "lizard") is an extinct genus of ornithopod dinosaur from the Upper Cretaceous of Provincia de Santa Cruz, Argentina. The type (and only known) species is Loncosaurus argentinus, described by the famous Argentinian paleontologist Florentino Ameghino, but is considered a dubious name. Details on this animal are often contradictory, befitting a genus that was long confused for a theropod.

Emiliasaura (meaning "Emilia's lizard") is an extinct genus of iguanodontian ornithopod dinosaurs from the Early Cretaceous (Valanginian) Mulichinco Formation of Neuquén Province, Argentina. The genus contains a single species, Emiliasaura alessandrii, known from three individual specimens. Emiliasaura was initially described as a rhabdodontomorph. If this identification is correct, it would represent the oldest member of this clade and the first named from South America. However, a later analysis of rhabdodontomorphs failed to recover Emiliasaura within this clade, instead placing it as a sty

Hesperonyx (meaning "western claw") is an extinct genus of dryomorphan ornithopod dinosaur from the Late Jurassic Lourinhã Formation of Portugal. The genus contains a single species, Hesperonyx martinhotomasorum, known from bones of the fore- and hindlimbs.

Iyuku (meaning "hatchling", pronounced "eye-yoo-koo") is a genus of iguanodontian dinosaur from the Early Cretaceous Kirkwood Formation of South Africa. The type species is Iyuku raathi.