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Pachycephalosauria
Pachycephalosauria (; from Greek παχυκεφαλόσαυρος for 'thick headed lizards') is a clade of ornithischian dinosaurs. Along with Ceratopsia, it makes up the clade Marginocephalia. With the exception of two species, most pachycephalosaurs lived during the Late Cretaceous Period, dating between about 85.8 and 65.5 million years ago. They are exclusive to the Northern Hemisphere, all of them being found in North America and Asia. They were all bipedal, herbivorous/omnivorous animals with thick skulls. Skulls can be domed, flat, or wedge-shaped depending on the species, and are all heavily ossified. The domes were often surrounded by nodes and/or spikes. Partial skeletons have been found of several pachycephalosaur species, but to date no complete skeletons have been discovered. Often isolated skull fragments are the only bones that are found. Candidates for the earliest known pachycephalosaur include ''Ferganocephale adenticulatum'' from Middle Jurassic Period strata ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphaerotholus
''Sphaerotholus'' is a genus of pachycephalosaurid dinosaur from the Upper Cretaceous of the western United States and Canada. To date, three species have been described: the type species, ''S. goodwini'', from the Den-na-zin Member of the Kirtland Formation (Late Campanian) of San Juan County, New Mexico, San Juan County, New Mexico, USA; ''S. buchholtzae'', from the Hell Creek Formation (Late Maastrichtian) of western Carter County, Montana, Carter County, Montana, USA and the Frenchman Formation of Saskatchewan, Canada; and ''S. edmontonensis'', from the Horseshoe Canyon Formation of Alberta, Canada. History of discovery The etymology of ''Sphaerotholus'' is a combination of the Greek language, Greek ''sphaira'', meaning "ball", and ''tholos'', meaning "dome", and is a reference to the characteristically dome-shaped pachycephalosaurian skull (anatomy), skull. The survival of ''Sphaerotholus'' from the Campanian of New Mexico to the end of the Maastrichtian of Montana demonstr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goyocephale
''Goyocephale'' is an extinct genus of pachycephalosaurian ornithischian that lived in Mongolia during the Late Cretaceous about 76 million years ago. It was first described in 1982 by Altangerel Perle, Teresa Maryańska and Halszka Osmólska for a disarticulated skeleton with most of a skull, part of the forelimb and hindlimb, some of the pelvic girdle, and some vertebrae. Perle ''et al.'' named the remains ''Goyocephale lattimorei'', from the Mongolian гоё (''goyo''), meaning "decorated", and the Ancient Greek κεφαλή (''kephale''), for head. The species name honours Owen Lattimore. Description ''Goyocephale'' is known from a partial skull, including both mandibles, the skull roof, part of the occiput, part of the braincase region, the posterior skull, the premaxilla, and the maxilla. The posterior edge of the skull roof, at the edge of the squamosal bones, has many small bony bumps, which would have been the base of small horns in life. A feature shared with pachyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wannanosaurus
''Wannanosaurus'' (meaning " Wannan lizard", named after the location where it was discovered) is a genus of basal pachycephalosaurian dinosaur from the Maastrichtian Upper Cretaceous Xiaoyan Formation, about 80 million years ago ( mya) in what is now Anhui, China. The type species, ''Wannanosaurus yansiensis'', was described by Hou Lian-Hai in 1977. It is known from a single partial skeleton, including a partial skull roof and lower jaw, a femur and tibia, part of a rib, and other fragments. Because it has a flat skull roof with large openings, it has been considered primitive among pachycephalosaurs. Sometimes it has been classified as a member of the now-deprecated family Homalocephalidae, now thought to be an unnatural assembly of pachycephalosaurians without domed skulls. Although its remains are from a very small individual, with a femur length of ~8 centimeters (3.1 in) and an estimated overall length of about 60 cm (2 ft),Holtz, Thomas R. Jr. ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraminacephale
''Foraminacephale'' (meaning "foramina head") is a genus of pachycephalosaurid dinosaur from Late Cretaceous (Campanian stage) deposits of Canada. Description ''Foraminacephale'', as a pachycephalosaurid, was a small, bipedal herbivore with a thickened dome on its skull. In 2016, Gregory S. Paul estimated its length at , its weight at . In ''Foraminacephale'', the top surface of the dome is punctuated by many small pits, the eponymous foramina; the dome itself consists of a large, central lobe with a sloped frontal half, and two smaller lateral lobes at the front. The squamosal bone forms a tall bar of completely smooth bone underneath the dome, save for six bony nodes that line the bottom edge of the dome and an additional "corner" node just below. These features differentiate ''Foraminacephale'' from all other pachycephalosaurids. Unlike ''Stegoceras'', ''Hanssuesia'', and '' Colepiocephale'', the parietal bone of ''Foraminacephale'' (which constitutes the back part of the dom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya; their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stegoceras
''Stegoceras'' is a genus of pachycephalosaurid (dome-headed) dinosaur that lived in what is now North America during the Late Cretaceous period, about 77.5 to 74 million years ago (mya). The first specimens from Alberta, Canada, were described in 1902, and the type species ''Stegoceras validum'' was based on these remains. The generic name means "horn roof", and the specific name means "strong". Several other species have been placed in the genus over the years, but these have since been moved to other genera or deemed junior synonyms. Currently only ''S. validum'' and ''S. novomexicanum'', named in 2011 from fossils found in New Mexico, remain. The validity of the latter species has also been debated. ''Stegoceras'' was a small, bipedal dinosaur about long, and weighed around . The skull was roughly triangular with a short snout, and had a thick, broad, and relatively smooth dome on the top. The back of the skull had a thick "shelf" over the occiput, and it had a thick ridge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinocephale
''Sinocephale'' (meaning "Chinese head") is a genus of pachycephalosaurid dinosaur that lived in Inner Mongolia, China during the Cretaceous period. The only species, ''Sinocephale bexelli'', was originally named as a species of the genus ''Troodon'' in 1953, and later transferred to the genus ''Stegoceras''. After decades of being considered dubious, it was re-evaluated in 2021 and recognized as a valid taxon, being given a unique generic name. The original holotype was lost, with modern research conducted using rediscovered plaster casts. Scant material makes for limited knowledge of its life appearance, but it is distinguished by an embayment on the back of the domed skull, which would give it a heart shape as seen from above. It is potentially the oldest known pachycephalosaurid and falls within the subset of the family called Pachycephalosaurinae, related to animals such as ''Stegoceras''. The geologic context of the species has been historically unclear but it is currently th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tylocephale
''Tylocephale'' (meaning "swollen head", from the Greek ''τυλη'' meaning 'callus' or 'hard swelling' and ''κεφαλη'' meaning 'head') is a genus of pachycephalosaurid dinosaur from the Late Cretaceous period. It was a herbivorous dinosaur, reaching in length and in body mass. It had the tallest dome of any known pachycephalosaur. ''Tylocephale'' lived during the Campanian stage, around 74 million years ago. It was discovered in the Khulsan locality of the Barun Goyot Formation, Mongolia sometime between 1965 and 1971. The type species is ''T. gilmorei'', described by Teresa Maryańska and Osmólska in 1974 based on a partial skull (specimen ZPAL MgD-I/105). Pachycephalosaurids evolved in Asia and then migrated into North America, thus it is likely that ''Tylocephale'' migrated back into Asia. It is closely related to ''Prenocephale''. See also * Timeline of pachycephalosaur research This timeline of pachycephalosaur research is a chronological listing of event ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alaskacephale
''Alaskacephale'' was a genus of pachycephalosaurid dinosaur from the Prince Creek Formation, that lived in the early Maastrichtian stages of the Late Cretaceous (around 71 to 69 million years ago). Discovery ''Alaskacephale'' was named by Robert Sullivan in 2006. The genus name refers to Alaska, where the holotype was discovered, combined with the Greek ''kephale'', meaning head. The species name, ''gangloffi'', honors paleontologist Roland Gangloff. The only known specimen of ''A. gangloffi'' is the holotype UAM AK-493-V-001, found in 1999, a nearly complete left squamosal with a characteristic array of polygonal nodes. The dimensions of this bone suggest that ''A. gangloffi'' was about half the size of ''Pachycephalosaurus wyomingensis'' or three quarters the size of ''Prenocephale'', and about the same size as '' Sphaerotholus edmontonensis'' and ''Foraminacephale''. The specimen was previously described by Gangloff ''et al.'' (2005) as an unnamed pachycephalosaurid, possibl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia and Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lexico
Lexico was a dictionary website that provided a collection of English and Spanish dictionaries produced by Oxford University Press (OUP), the publishing house of the University of Oxford. While the dictionary content on Lexico came from OUP, this website was operated by Dictionary.com, whose eponymous website hosts dictionaries by other publishers such as Random House. The website was closed and redirected to Dictionary.com on 26 August 2022. Before the Lexico site was launched, the '' Oxford Dictionary of English'' and ''New Oxford American Dictionary'' were hosted by OUP's own website Oxford Dictionaries Online (ODO), later known as Oxford Living Dictionaries. The dictionaries' definitions have also appeared in Google definition search and the Dictionary application on macOS, among others, licensed through the Oxford Dictionaries API. History In the 2000s, OUP allowed access to content of the ''Compact Oxford English Dictionary of Current English'' on a website called AskOx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic period (), and the Classical period (). Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Epic and Classical periods of the language. From the Hellenistic period (), Ancient Greek was followed by Koine Greek, which is regarded as a separate historical stage, although its earliest form closely resembles Attic Greek and its latest form approaches Medieval Greek. There were several regional dialects of Ancient Greek, of which Attic Greek developed into Koine. Dia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
