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Clypeodonta
Neornithischia ("new ornithischians") is a clade of the dinosaur order Ornithischia. It is the sister group of the Thyreophora within the clade Genasauria. Neornithischians are united by having a thicker layer of asymmetrical enamel on the inside of their lower teeth. The teeth wore unevenly with chewing and developed sharp ridges that allowed neornithischians to break down tougher plant food than other dinosaurs. Neornithischians include a variety of basal forms historically known as " hypsilophodonts", including the Parksosauridae; in addition, there are derived forms classified in the groups Marginocephalia and Ornithopoda. The former includes clades Pachycephalosauria and Ceratopsia, while the latter typically includes '' Hypsilophodon'' and the more derived Iguanodontia. Classification Neornithischia was first named by Cooper in 1985 and defined as "all genasaurians more closely related to ''Parasaurolophus walkeri'' than to '' Ankylosaurus magniventris'' or '' Stegos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithopoda
Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world, dominating the North American land. 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 apex of diversity and ecological dominance in the hadrosaurids (colloquially known as 'duck-bills'), before they were wiped out by the Cretaceous–Paleogene extinction event along with all other non- avian dinosaurs. Members are known from all seven continents, though they are generally rare in the Southern Hemisphere. History of research In 1870, Thomas Henry Huxley listed Iguanodontidae (coined by Cope a year earlier) as one of his three families of dinos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jeholosauridae
Jeholosaurids were herbivorous neornithischian dinosaurs from the Cretaceous Period (Aptian - Cenomanian). The family was first proposed by Han ''et al.'' in 2012. The jeholosaurids were defined as all neornithischians more closely related to ''Jeholosaurus shangyuanensis'' than to ''Hypsilophodon foxii'', ''Iguanodon bernissartensis'', ''Protoceratops andrewsi'', ''Pachycephalosaurus wyomingensis'', or ''Thescelosaurus neglectus''. The Jeholosauridae includes the type genus '' Jeholosaurus'', and also possibly '' Yueosaurus'', '' Changchunsaurus'', and ''Haya''.Boyd CA. (2015) The systematic relationships and biogeographic history of ornithischian dinosaurs. PeerJ 3:e1523 https://doi.org/10.7717/peerj.1523 The cladogram below results from analysis by Herne ''et al.'', 2019, which added '' Changchunsaurus'' and ''Haya'' to Jeholosauridae, but moved '' Yueosaurus'' to the sister family Thescelosauridae Thescelosauridae is a clade of neornithischians from the Cretaceous of Asia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypsilophodon
''Hypsilophodon'' (; meaning "''Hypsilophus''-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. The first remains of ''Hypsilophodon'' were found in 1849; the type species, ''Hypsilophodon foxii'', was named in 1869. Abundant fossil discoveries were made on the Isle of Wight, giving a good impression of the build of the species. It was a small, agile bipedal animal with an herbivorous or possibly omnivorous diet, measuring long and weighing . It had a pointed head equipped with a sharp beak used to bite off plant material, much like modern day parrots. Older studies have given rise to a number of misconceptions about ''Hypsilophodon'' that it was an armored, arboreal animal and that it could be found in areas outside of Wight. During the past decades, new researches have gradually shown this to be incorrect. Discov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fulgurotherium
''Fulgurotherium'' (meaning "Lightning beast") is the name given to a genus of ornithischian dinosaur from the Late Cretaceous ( Cenomanian) Griman Creek Formation. It lived in what is now Australia. Etymology The genus name is derived from Latin ''fulgur'', "lightning", and Greek ''therion'', "beast", a reference to the Lightning Ridge site in New South Wales. The specific name means "southern" in Latin. Its name is an unusual example of a name in which -''therium'' was used for an animal which is not an extinct mammal. History and classification The holotype of ''Fulgurotherium australe'' was first mention by British paleontologist Arthur Smith Woodward in 1909 along with several more fossils in the collection of the British Museum that had been collected from the Cenomanian Griman Creek Formation strata in Lightning Ridge in New South Wales, Australia.Agnolin, F. L., M. D. Ezcurra, D. F. Pais, and S. W. Salisbury. 2010. A reappraisal of the Cretaceous non-avian dinosa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypsilophodont
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 Elasmaria. A 2014 analysis by Norman recovered a grouping of ''Hypsilophodon'', Rhabdodontidae and '' Tenontosaurus'', which he referred to as Hypsilophodontia. All other analyses from around the same time have instead found these latter taxa to be within Iguanodontia. Linnaean usage Hypsilophodontidae was named originally in 1882 by Louis Dollo, as a family to include '' Hypsilopho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parksosauridae
Thescelosauridae is a clade of neornithischians from the Cretaceous of Asia, North America and possibly South America. The group was originally used as a name by Charles M. Sternberg in 1937, but was not formally defined until 2013, where it was used by Brown and colleagues as the group uniting ''Thescelosaurus'' and ''Orodromeus'', based on their phylogenetic results. During a phylogenetic revision of neornithischians by Clint Boyd in 2015, the authorship of Thescelosauridae was given to Brown and colleagues, which meant that the similar name Parksosauridae, informally defined in 2002 by Buchholz, would have had priority over Thescelosauridae. The two clades had slightly different definitions, with Parksosauridae referring to all animals closer to ''Parksosaurus'' than ''Hypsilophodon'', but they contained the same taxa so Boyd used Parksosauridae under the assumption it had priority. However, in formalizing the clade following the regulations of the PhyloCode, Madzia, Boyd, and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithischia
Ornithischia () is an extinct order 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 "of a bird", and ' (), plural ', meaning "hip joint". However, birds are only distantly related to this group as birds are theropod dinosaurs. Ornithischians with well known anatomical adaptations include the ceratopsians or "horn-faced" dinosaurs (e.g. '' Triceratops''), the pachycephalosaurs or "thick-headed" dinosaurs, the armored dinosaurs ( Thyreophora) such as stegosaurs and ankylosaurs, and the ornithopods. There is strong evidence that certain groups of ornithischians lived in herds, often segregated by age group, with juveniles forming their own flocks separate from adults. Some were at least partially covered in filamentous (hair- or feather- like) pelts, and there is much debate over whether these filamen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyreophora
Thyreophora ("shield bearers", often known simply as "armored dinosaurs") is a group of armored ornithischian dinosaurs that lived from the Early Jurassic until the end of the Cretaceous. Thyreophorans are characterized by the presence of body armor lined up in longitudinal rows along the body. Primitive forms had simple, low, keeled scutes or osteoderms, whereas more derived forms developed more elaborate structures including spikes and plates. Most thyreophorans were herbivorous and had relatively small brains for their body size. Thyreophora includes various subgroups, including the suborders Ankylosauria and Stegosauria. In both the suborders, the forelimbs were much shorter than the hindlimbs, particularly in stegosaurs. The clade has been defined as the group consisting of all species more closely related to '' Ankylosaurus'' than to ''Triceratops''. Thyreophora is the sister group of Cerapoda within Genasauria. Groups of thyreophorans Basal thyreophorans Basal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genasauria
Genasauria 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. A distinguishing postcranial feature of Genasauria is a pubic peduncle of the ilium that is less robust than the ischial peduncle. Genasauria is commonly divided into Neornithischia and Thyreophora. Neornithischia is characterized by asymmetrical distributions of enamel covering the crowns of the cheek teeth, an open acetabulum, and a laterally protruding ischial peduncle of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland,British Geological Survey. 2011Stratigraphic framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf: research report RR/11/06 British Geological Survey, Keyworth, Nottingham. the Daohugou Beds in China, the Itat Formation in Russia, and the Isalo III Formation of western Madagascar. Paleogeography During the Middle Jurassic Epoch, Pangaea began to separate into Laurasia and Gondwana, and the Atlantic Ocean formed. Eastern Laurasia was tectonically active as the Cimmerian plate continued to collide with Laurasia's southern coast, completely closing the Paleo-Tethys Ocean. A subd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marginocephalia
Marginocephalia (/mär′jə-nō-sə-făl′ē-ən/ Latin: margin-head) is a clade of ornithischian dinosaurs that is characterized by a bony shelf or margin at the back of the skull. These fringes were likely used for display. There are two clades included in Marginocephalia: the thick-skulled Pachycephalosauria and the horned Ceratopsia. All members of Marginocephalia were primarily herbivores. They basally used gastroliths to aid in digestion of tough plant matter until they convergently evolved tooth batteries in Neoceratopsia (or "new Ceratopsia") and Pachycephalosauria. Marginocephalia first evolved in the Jurassic Period and became more common in the Cretaceous. They are basally small facultative quadrupeds while derived members of the group are large obligate quadrupeds. Primitive marginocephalians are found in Asia, but the group migrated upwards into North America. Pachycephalosaurs, or "thick-headed reptiles", have primitive features that include basally small sized bod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
