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Pachycephalosaurids
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachycephalosaurus
''Pachycephalosaurus'' (; meaning "thick-headed lizard", from Greek ''pachys-/'' "thick", ''kephale/'' "head" and ''sauros/'' "lizard") is a genus of pachycephalosaurid dinosaurs. The type species, ''P. wyomingensis'', is the only known species, but some researchers argue that there might be a second species, ''P. spinifer''. It lived during the Late Cretaceous Period (Maastrichtian stage) of what is now North America. Remains have been excavated in Montana, South Dakota, Wyoming, and Alberta. It was a herbivorous creature which is primarily known from a single skull and a few extremely thick skull roofs, at 22 centimetres (9 inches) thick. More complete fossils have been found in recent years. ''Pachycephalosaurus'' was among the last non-avian dinosaurs before the Cretaceous–Paleogene extinction event. The genus ''Tylosteus'' has been synonymized with ''Pachycephalosaurus'', as have the genera ''Stygimoloch'' and ''Dracorex'' in recent studies. Like other pachycephalosaurids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachycephalosaurus Wyomingensis
''Pachycephalosaurus'' (; meaning "thick-headed lizard", from Greek ''pachys-/'' "thick", ''kephale/'' "head" and ''sauros/'' "lizard") is a genus of pachycephalosaurid dinosaurs. The type species, ''P. wyomingensis'', is the only known species, but some researchers argue that there might be a second species, ''P. spinifer''. It lived during the Late Cretaceous Period (Maastrichtian stage) of what is now North America. Remains have been excavated in Montana, South Dakota, Wyoming, and Alberta. It was a herbivorous creature which is primarily known from a single skull and a few extremely thick skull roofs, at 22 centimetres (9 inches) thick. More complete fossils have been found in recent years. ''Pachycephalosaurus'' was among the last non-avian dinosaurs before the Cretaceous–Paleogene extinction event. The genus ''Tylosteus'' has been synonymized with ''Pachycephalosaurus'', as have the genera ''Stygimoloch'' and ''Dracorex'' in recent studies. Like other pachycephalosaurids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrotholus
''Acrotholus'' (Greek for "highest dome"- akros meaning highest and tholos meaning dome) is an extinct genus of pachycephalosaur dinosaur that lived during the Santonian of the late Cretaceous, in the Milk River Formation of Canada. The type species, ''A. audeti'', was named after Roy Audet allowing access to his ranch leading to the discovery of the species. The discovery of this specimen lead to several new revelations in the fossil records questioning the preservation of small-bodied organisms along with the evolution of early pachycephalosaurs. The iconic cranial dome found on ''Acrotholus'' makes it one of the earliest indisputable known members of the pachycephalosaur family. Like others of its clade, ''Acrotholus'' was a bipedal herbivore characterized by a dome-shaped head. The dome had often been associated with intra-species combat though exact method of contact have been debated. History of discovery The holotype was found in the Deadhorse Coulee Member of the Milk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitholus
''Gravitholus'' (meaning 'heavy dome') was a genus of pachycephalosaurid dinosaur from the late Cretaceous period (Campanian stage, around 75 million years ago). It was a pachycephalosaur, and like other pachycephalosaurids the skull roof formed a thick dome made of dense bone, which may have been used in head-butting contests over mates or territory. It lived in what is now Alberta, Canada, and was described in 1979 by W. P. Wall and Peter Galton. The type species is ''Gravitholus albertae''. There is some debate amongst paleontologists as to whether the animal represents a distinct genus, or if it may be synonymous with ''Stegoceras''. Recent publications indicate it may be a valid genus. ''Gravitholus'' is one of several pachycephalosaurids known from Dinosaur Park, including ''Stegoceras validum'', ''Hanssuesia sternbergi'', and '' Foraminacephale brevis''. It is unclear whether all of these species would have lived in the area at the same time. A 2020 CSVP abstract found '' ... [...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] |
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] |
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] |
Texacephale
''Texacephale'' is a pachycephalosaurid dinosaur from the Campanian stage of the Late Cretaceous. Its fossils come from the Aguja Formation of Big Bend National Park, in Texas, and were described in 2010 by Longrich, Sankey and Tanke. The generic name means Texas + "head" (''kephale'' in Greek) in reference to its place of discovery, and the specific name honors Wann Langston. Discovery The holotype specimen of ''Texacephale'', LSUMNS 20010, is composed of fused frontals and parietals. A second specimen, LSUMNS 20012, is composed of an incomplete frontoparietal dome. It was found in the same WPA quarries that produced ''Agujaceratops'', and may have been excavated and tossed aside, being mistaken for a rock or concretion, before being picked up decades later. According to the team, the fossilized dome of the animal possessed five to six vertical flanges on each lateral side, connecting it with the postorbital bone. The team interpreted these structures as interlocking "gear ... [...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] |
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] |
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