Ornithischia

Ornithischia () is an extinct clade of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name Ornithischia, or "bird-hipped", reflects this similarity and is derived from the Greek stem ' (), meaning "bird", and ' (), meaning "hip". However, as birds are theropod dinosaurs, they are only distantly related to this group.

Lesothosaurus is a monospecific genus of ornithischian dinosaur that lived during the Early Jurassic in what is now South Africa and Lesotho. It was named by paleontologist Peter Galton in 1978, the name meaning "lizard from Lesotho". The genus has only one valid species, Lesothosaurus diagnosticus. Lesothosaurus is one of the most completely-known early ornithischians, based on numerous skull and postcranial fossils from the Upper Elliot Formation. It had a simpler tooth and jaw anatomy than later ornithischians, and may have been omnivorous in some parts of the year.

Pisanosaurus ( ) is an extinct genus of early dinosauriform, likely an ornithischian or silesaurid, from the Late Triassic of Argentina. It was a small, lightly built, ground-dwelling herbivore, that could grow up to an estimated long. Only one species, the type, Pisanosaurus mertii, is known, based on a single partial skeleton discovered in the Ischigualasto Formation of the Ischigualasto-Villa Unión Basin in northwestern Argentina. This part of the formation has been dated to the late Carnian, approximately 229 million years ago.

Fabrosaurus ( ) is a dubious extinct genus of ornithischian dinosaur that lived during the Early Jurassic during the Hettangian to Sinemurian stages (199 - 189 mya).

Eocursor (meaning "dawn runner") is genus of basal ornithischian dinosaur that lived in what is now South Africa during the Early Jurassic. Remains of this animal have been found in the Upper Elliot Formation and it is among the most completely known early ornithischians, shedding new light on the origin of the group.

Serendipaceratops (meaning "serendipitous horned face") is a genus of herbivorous ornithischian dinosaur, possibly an ankylosaur, from the early Cretaceous Period of Australia. The type species, S. arthurcclarkei, was named in 2003.

Laquintasaura is a genus of Venezuelan ornithischian dinosaur containing a single species, Laquintasaura venezuelae. It is known for being one of the most primitive ornithischians in the fossil record, as well as the first dinosaur to have been identified from Venezuela. The name is derived from the La Quinta Formation, where it was discovered, and the feminine Greek suffix for lizard, with the specific name referring to the country of Venezuela. It is known from hundreds of fossil elements, all derived from a single extensive bonebed locality. Initially discovered by French palaeontologists,

Notoceratops (meaning "southern horned face") is a dubious genus of extinct ornithischian dinosaur. The genus was described based on an incomplete, toothless left dentary (now lost) from the Late Cretaceous of Patagonia (in Argentina), probably dating to the Campanian or Maastrichtian. Initially classified as a putative ceratopsian found in the Lago Colhué Huapi Formation, the lost fragmentary holotype precludes confident referral of this taxon within ornithischians, with some researchers suggesting that it belongs to a hadrosaur instead.

Amtosaurus () is a genus of ornithischian dinosaur based on a fragmentary skull collected from the Late Cretaceous (Cenomanian to Turonian) Bayanshiree Formation of Mongolia and originally believed to represent an ankylosaurid. Hadrosaurid affinities have also been suggested. However, according to Parish and Barrett, this specimen is too fragmentary to be reliably classified beyond an indeterminate ornithischian. A second species assigned to the genus, A. archibaldi, has become the basis of a valid ankylosaurid taxon, Bissektipelta.

Alocodon is a genus of ornithischian dinosaur known from multiple teeth from the Middle or Late Jurassic Cabaços Formation of Portugal, and also the Forest Marble and Chipping Norton Formations of England. A single species is known, A. kuehnei.

Ferganocephale is a dubious genus of neornithischian dinosaur. It was from the Middle Jurassic Balabansai Svita of Kyrgyzstan. The type and only species is F. adenticulatum.

Gongbusaurus is a genus of ornithischian, perhaps ornithopod, dinosaur that lived between about 160 and 157 million years ago, in the Late Jurassic period. A small herbivore, it is very poorly known. Two species have been assigned to it, but as the original name is based on teeth, there is no concrete evidence to connect the two species. Its fossils have been found in China.

Archaeocursor (meaning "old runner") is an extinct genus of basal ornithischian dinosaurs from the Early Jurassic Ziliujing Formation of China. The genus contains a single species, A. asiaticus, known from a single femur. Archaeocursor represents the oldest and most basal ornithischian described from Asia.

Trimucrodon is a genus of ornithischian dinosaur from the Late Jurassic Lourinhã Formation of Portugal. The type, and currently only, species is T. cuneatus.

Claorhynchus (meaning "broken beak", as it is based on broken bones from the snout region) is a dubious genus of cerapodan dinosaur with a confusing history behind it. It has been considered to be both a hadrosaurid and a ceratopsid, sometimes the same as Triceratops, with two different assignments as to discovery formation and location, and what bones make up its type remains.