HeterodontosauridaeHeterodontosauridae is a family of ornithischian dinosaurs that were likely among the most basal (primitive) members of the group. Their phylogenetic placement is uncertain but they are most commonly found to be primitive, outside of the group Genasauria. Although their fossils are relatively rare and their group small in numbers, they have been found on all continents except Australia and Antarctica, with a range spanning the Early Jurassic to the Early Cretaceous.
PisanosaurusPisanosaurus (pIsæn@'sɔːr@s) 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.
GenasauriaGenasauria is a clade of extinct beaked, primarily herbivorous dinosaurs. Paleontologist Paul Sereno first named Genasauria in 1986. The name Genasauria is derived from the Latin word gena meaning ‘cheek’ and the Greek word saúra (σαύρα) meaning ‘lizard.’ It is hypothesized that Genasauria had diverged from Lesothosaurus by the Early Jurassic. Cranial features that characterize Genasauria include a medial offset of the maxillary dentition, a sprout-shaped mandibular symphysis, moderately sized coronoid process, and an edentulous (without teeth) anterior portion of the premaxilla.
EchinodonEchinodon is a genus of heterodontosaurid dinosaur that lived during the earliest Cretaceous of southern England and possibly western France in the Berriasian epoch. The first specimens were jaw bones named Echinodon becklesii by Sir Richard Owen in 1861, and since their original description only additional teeth have been discovered. The specific name honours collector Samuel Beckles who discovered the material of Echinodon and many other taxa from across England, while the genus name translates as "prickly tooth" in reference to the dental anatomy of the taxon.
HeterodontosaurusHeterodontosaurus is a genus of heterodontosaurid dinosaur that lived during the Early Jurassic, 200–190 million years ago. Its only known member species, Heterodontosaurus tucki, was named in 1962 based on a skull discovered in South Africa. The genus name means "different toothed lizard", in reference to its unusual, heterodont dentition; the specific name honours G. C. Tuck, who supported the discoverers. Further specimens have since been found, including an almost complete skeleton in 1966.
PegomastaxPegomastax is a genus of heterodontosaurid dinosaur that lived during the Early Jurassic of South Africa. The only known specimen was discovered in a 1966-1967 expedition in Transkei District of Cape Province, but wasn't described until 2012 when Paul Sereno named it as the new taxon Pegomastax africana. The genus name is derived from the Greek for "strong jaw", and the species name describes the provenance of Africa; it was originally spelled africanus, was corrected to africana to align with the gender of the genus name.
StegosaurusStegosaurus (ˌstɛɡəˈsɔːrəs; roof-lizard) is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Fossils of the genus have been found in the western United States and in Portugal, where they are found in Kimmeridgian- to Tithonian-aged strata, dating to between 155 and 145 million years ago. Of the species that have been classified in the upper Morrison Formation of the western US, only three are universally recognized: S.
