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Pachycephalosaurs
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] |
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] |
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] |
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 bodi ... [...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] |
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] |
Homalocephale
''Homalocephale'' (from Greek ὁμαλός, ''homalos'', "even", and κεφαλή, ''kephalē'', "head") is a genus of pachycephalosaurid dinosaur that lived during the Late Cretaceous period of what is now the Nemegt Formation, Mongolia, about 70 million years ago. The genus was described in 1974 by Halszka Osmólska and Teresa Maryańska, and consists of a single species, ''H. calathocercos''. Though ''Homalocephale'' has been regarded as a synonym (and juvenile form) of ''Prenocephale'', juvenile specimens of the latter indicate that they were distinct. ''Homalocephale'' was long and possibly herbivorous. Discovery The type species, ''H. calathocercos'', was described from an incomplete skull and postcranial material (holotype MPC-D 100/1201) from the Nemegt locality of the Nemegt Formation. The specimen has large openings on the top of the skull, a distinct frontoparietal suture, low and long infratemporal fenestrae, and a large, round eye socket. The forehead is notably ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prenocephale
''Prenocephale'' (meaning "sloping head") is a genus of small pachycephalosaurid dinosaur from the Late Cretaceous Nemegt Formation of Mongolia. It was similar in many ways to its close relative, ''Homalocephale''. Description Adult ''Prenocephale'' measured in length and in body mass. Unlike the flattened wedge-shaped skull of ''Homalocephale'' (a possible juvenile trait also potentially seen in early growth stages of '' Pachycephalosaurus''), the head of ''Prenocephale'' was rounded and sloping. The dome had a row of small bony spikes and bumps. Like some other pachycephalosaurs, ''Prenocephale'' is known only from skulls and a few other small bones. For this reason, reconstructions usually depict ''Prenocephale'' as sharing the basic body plan common to all of the other Pachycephalosauria: a stout body with a short, thick neck, short forelimbs and tall hind legs. The head of ''Prenocephale'' was comparable to that of ''Stegoceras'', albeit with closed supratemporal fenestr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hanssuesia
''Hanssuesia'' is a genus of pachycephalosaurid dinosaurs from the late Cretaceous period. It lived in what is now Alberta and Montana, and contains the single species ''Hanssuesia sternbergi''. ''Hanssuesia'' is based on a skull dome originally named ''Troodon sternbergi'' by Barnum Brown and Erich Maren Schlaikjer in 1943. The specific name honoured Charles Mortram Sternberg who found the dome in 1928 near Steveville in south Alberta. In 1945, it was transferred to ''Stegoceras'' by C.M. Sternberg himself, as a ''Stegoceras sternbergi''. The genus ''Hanssuesia'' was first named by Robert M. Sullivan in 2003. It honours paleontologist Hans-Dieter Sues. In the publication also the spelling variant "Hanssuessia" appeared; the same year Sullivan chose for ''Hanssuesia'' as the valid name. Its type species is ''Troodon sternbergi'', the '' combinatio nova'' is ''Hanssuesia sternbergi''. ''H. sternbergi'' is known from the holotype NMC 8817 and six referred specimens (mainly fro ... [...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] |
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] |
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] |
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