Prenocephale

Prenocephale was a small pachycephalosaurid dinosaur genus from the Late Cretaceous (Campanian) of Mongolia and was similar in many ways to its close relative, Homalocephale, which may simply represent Prenocephale juveniles.

Prenocephale
Temporal range: Late Cretaceous, 80–75 Ma
Prenocephale prenes
Cast of a P. prenes skull
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Family: Pachycephalosauridae
Genus: Prenocephale
Maryańska & Osmólska, 1974
Species
  • P. prenes Maryńska & Osmólska, 1974 (type)
Synonyms

Description

Prenocephale bickering
Life restoration

Adult Prenocephale probably weighed around 130 kilograms (290 lb) and measured around 2.4 metres (8 ft) long. 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. It lived in what is now Mongolia, but in high upland forests, not the dry deserts of Mongolia today.[1]

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 fenestrae. Also, the paired grooves above the supraorbitals/prefrontals (along with a posterior parietal that restricts the frontal dome) are absent in Prenocephale. This differentiates the species from Stegoceras, as such features are common in the latter. The North American Sphaerotholus was considered a synonym of Prenocephale by Sullivan (2003), but Longrich et al. (2010) and Schott and Evans (2016) kept it as a distinct genus based on cladistic analysis. Homalocephale has been viewed as a possible juvenile of Prenocephale due to the lack of a dome and its discovery in the same location and chronological interval, but new specimens of Prenocephale, including a juvenile specimen, suggest that Homalocephale, even if its holotype is a juvenile, is distinct.[2][3][4]

Classification

Prenocephale prenes5991
Front view of skull

Prenocephale is a member of the Pachycephalosauria, a large clade of herbivorous/omnivorous dinosaurs from the Late Cretaceous.

Robert Sullivan considered Foraminacephale, "Prenocephale" edmontonensis, and Sphaerotholus goodwini to form a clade with the Asian taxon P. prenes. He considered Tylocephale the sister taxon to the Prenocephale clade, while sinking Sphaerotholus buchholtzae as a subjective junior synonym of "P." edmontonensis.[5] They all possess a distinct row of nodes on the squamosal and parietal areas of the skull roof.

Below is a cladogram modified from Evans et al., 2013.[6]

 Pachycephalosauria 

Wannanosaurus yansiensis

 Pachycephalosauridae 

Colepiocephale lambei

Hanssuesia sternbergi

Stegoceras novomexicanum

Stegoceras validum

Goyocephale lattimorei

Homalocephale calathocercos

Tylocephale gilmorei

Foraminacephale brevis

Amtocephale gobiensis

Acrotholus audeti

Prenocephale prenes

Alaskacephale gangloffi

Pachycephalosaurus wyomingensis

Sphaerotholus buchholtzae

Sphaerotholus goodwini

Paleobiology

PrenocephaleNV
Restoration of flank-butting behavior

As with most of its relatives, scientists do not yet know what these dinosaurs ate. However the premaxillary teeth and muzzle are not as wideset as in its relative Stegoceras, indicating different feeding preferences, possibly that Prenocephale was a more selective forager. Some scientists suggest that it may have been an omnivore, eating both plants and insects. However, most experts agree that Prenocephale (and the other pachycephalosaurs) browsed on leaves and fruit.

See also

References

  • T. Maryanska and H. Osmolska. 1974. Pachycephalosauria, a new suborder of ornithischian dinosaurs. Palaeontologia Polonica 30:45-102.
  1. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 137. ISBN 1-84028-152-9.
  2. ^ Longrich, N.R., Sankey, J. and Tanke, D., 2010. Texacephale langstoni, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA. Cretaceous Research, . doi:10.1016/j.cretres.2009.12.002
  3. ^ Re: Sphaerotholus
  4. ^ David C. Evans, Shoji Hayashi, Kentaro Chiba, Mahito Watabe, Michael J. Ryan, Yuong-Nam Lee, Philip J. Currie, Khishigjav Tsogtbaatar, Rinchen Barsbold. (2017) Morphology and histology of new cranial specimens of Pachycephalosauridae (Dinosauria: Ornithischia) from the Nemegt Formation, Mongolia. Palaeogeography, Palaeoclimatology, Palaeoecology.
  5. ^ Robert M. Sullivan (2003). Revision of the dinosaur Stegoceras Lambe (Ornithischia, Pachycephalosauridae). of Vertebrate Paleontology: Vol. 23, No. 1, pp. 181–207.
  6. ^ Evans, D. C.; Schott, R. K.; Larson, D. W.; Brown, C. M.; Ryan, M. J. (2013). "The oldest North American pachycephalosaurid and the hidden diversity of small-bodied ornithischian dinosaurs". Nature Communications. 4: 1828. Bibcode:2013NatCo...4E1828E. doi:10.1038/ncomms2749. PMID 23652016.
1974 in paleontology

Paleontology or palaeontology (from Greek: paleo, "ancient"; ontos, "being"; and logos, "knowledge") is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1974.

Acrotholus

Acrotholus (Greek for "highest dome"- akros meaning highest and tholos meaning dome) is an extinct genus of ornithischian dinosaur that lived during the Santonian of the late Cretaceous, in the Milk River Formation. The type species, 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 the earliest indisputable known member 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.

Alaskacephale

Alaskacephale was a genus of pachycephalosaurid dinosaur that lived in the late Campanian to Maastrichtian stages of the Late Cretaceous (around 80 to 69 million years ago).

Alaskacephale was named by Robert Sullivan in 2006. The genus name refers to Alaska, where the fossil was found in the Prince Creek Formation. The species name, gangloffi, honors paleontologist Roland Gangloff. The only known specimen of A. gangloffi is the holotype, 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 "Prenocephale" edmontonensis and Foraminacephale.The specimen was previously described by Gangloff et al. (2005) as an unnamed pachycephalosaurid, possibly a Pachycephalosaurus. Gangloff et al. described the squamosal as having an interdigitated suture with the quadrate, a feature previously described only in Pachycephalosaurus. Sullivan (2006) opined that this "suture" is instead a breakage point in both Alaskacephale and Pachycephalosaurus, so it could not be used to unite the two taxa.

Bagaceratopidae

Bagaceratopidae is a family of neoceratopsian dinosaurs. It was named by Alifanov in 2003 but no definition has been proposed. Because of lacking of the definition, Bagaceratopidae was considered inactive by Paul Sereno in 2005. Alifanov in 2003 classified to this family four genera: Bagaceratops, Breviceratops, Lamaceratops and Platyceratops and in a publication from 2008 he included in Bagaceratopidae also Magnirostris and newly described genus Gobiceratops. Alifanov suggested also that Bagaceratopidae, unlike other neoceratopsian families, is of Paleoasiatic origin.Bagaceratopids existed during the late Cretaceous period, between about 85.8 and 70.6 million years ago.

Bainoceratops

Bainoceratops (Bain: mountain, keras: horn, ops: face) is a genus of ceratopsian dinosaur from the late Campanian in the Late Cretaceous. This ceratopsian was first described by Tereschenko and Alifanov in 2003. Its fossils were found in southern Mongolia.

Breviceratops

Breviceratops (meaning "short horn face") was a herbivorous ceratopsian dinosaur from the Late Cretaceous of Mongolia.

Chaoyangsauridae

Chaoyangsauridae is a family of ceratopsian dinosaurs. They are among the earliest known marginocephalian dinosaurs, with remains dating to about 160 million years ago, during the Late Jurassic period. Members of this group had sharp beaks for snipping off leaves to eat, and a very small frill.

Four dinosaur genera, Chaoyangsaurus, Xuanhuaceratops, Yinlong and Hualianceratops, are usually considered to belong to the Chaoyangsauridae. All four animals are more primitive (or basal) than both Psittacosaurus and neoceratopsians.

Foraminacephale

Foraminacephale (meaning "foramina head") is a genus of pachycephalosaurid dinosaur from Late Cretaceous (Campanian stage) deposits of Canada.

Gobiceratops

Gobiceratops is a genus of ceratopsian dinosaur from the Upper Cretaceous of Mongolia. It is based on a skull that is 3.5 centimeters (1.4 inches) long, from the Khermin Tsav locality in the Barun Goyot Formation of southern Mongolia; the type individual was young. Gobiceratops is thought to have been related to Bagaceratops, and a member of Bagaceratopidae. It was described in 2008 by Alifanov. The type species is G. minutus.

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 Perle, Teresa Maryańska and 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 goyo, meaning "decorated", and the Ancient Greek kephale, for head. The species name honours Owen Lattimore.

Gryphoceratops

Gryphoceratops is an extinct genus of leptoceratopsid ceratopsian dinosaur known from the Late Cretaceous of Alberta, southern Canada.

Helioceratops

Helioceratops is a genus of neoceratopsian dinosaur from the Middle Cretaceous of China. The type species is H. brachygnathus, described in 2009 by a group of paleontologists led by Jin Liyong. Helioceratops was discovered in the Quantou Formation of China's eastern Jilin province and is known mostly from skull fragments. It reached a length of around 1.3 m (4.3 ft) and may have shared its habitat with Changchunsaurus.

Homalocephale

Homalocephale (from Greek ωμαλος, homalos, "even", and κεφαλή, kephalē, "head") is a genus of dinosaur belonging to the pachycephalosaurid family, which lived during the late Cretaceous period of what is now Mongolia, 80 million years ago. The genus was described in 1974 by Osmólska & Teresa Maryańska, and consists of a single species, H. calathocercos, though this may be a synonym (and juvenile form) of Prenocephale. Homalocephale was 1.8 metres (6 ft) long and herbivorous.

Pachycephalosauria

Pachycephalosauria (; from Greek παχυκεφαλόσαυρος for 'thick headed lizards') is a clade of ornithischian dinosaurs. Along with Ceratopsia, it makes up the clade Marginocephalia. Genera include Pachycephalosaurus, Stegoceras, and Prenocephale. 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 of Kyrgyzstan and Stenopelix valdensis from Early Cretaceous strata of Germany, although R.M. Sullivan has doubted that either of these species are pachycephalosaurs.[2] In 2017, a phylogenetic analysis conducted by Han and colleagues identified Stenopelix as a member of the Ceratopsia.

Pachycephalosaurus

Pachycephalosaurus (; meaning "thick-headed lizard," from Greek pachys-/παχυς- "thick", kephale/κεφαλη "head" and sauros/σαυρος "lizard") is a genus of pachycephalosaurid dinosaurs. The type species, P. wyomingensis, is the only known species. It lived during the Late Cretaceous Period (Maastrichtian stage) of what is now North America. Remains have been excavated in Montana, South Dakota, and Wyoming. It was a herbivorous creature which is primarily known from a single skull and a few extremely thick skull roofs, though more complete fossils have been found in recent years. Pachycephalosaurus was one of the last non-avian dinosaurs before the Cretaceous–Paleogene extinction event. Another dinosaur, Tylosteus of western North America, has been synonymized with Pachycephalosaurus, as have the genera Stygimoloch and Dracorex in some recent studies.

Like other pachycephalosaurids, Pachycephalosaurus was a bipedal herbivore with an extremely thick skull roof. It possessed long hindlimbs and small forelimbs. Pachycephalosaurus is the largest known pachycephalosaur. The thick skull domes of Pachycephalosaurus and related genera gave rise to the hypothesis that pachycephalosaurs used their skulls in intra-species combat. This hypothesis has been disputed in recent years.

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, USA; S. buchholtzae, from the Hell Creek Formation (Late Maastrichtian) of western Carter County, Montana, USA; and S. edmontonense, from the Horseshoe Canyon Formation of Alberta, Canada.

Teresa Maryańska

Teresa Maryańska is a Polish paleontologist who has specialized in Mongolian dinosaurs, particularly pachycephalosaurians and ankylosaurians. Peter Dodson (1998 p. 9) claims that in 1974 Maryanska together with Halszka Osmólska were among the first "women to describe new kinds of dinosaurs". She is considered not only as one of Poland's but also one of the world's leading experts on dinosaurs.A member of the 1964, 1965, 1970, and 1971 Polish–Mongolian expeditions to the Gobi Desert, she has described many finds from these rocks, often with Halszka Osmólska. Among the dinosaurs she has described are:

Saichania and Tarchia (1977)

with Osmólska, Homalocephale, Prenocephale, and Tylocephale (and Pachycephalosauria) (1974), Bagaceratops (1975), and Barsboldia (1981)

and with Osmόlska and Altangerel Perle, Goyocephale (1982).Alan Feduccia notes that Maryanska and her colleagues (Osmólska and Wolsan) produced in 2002 the "most impressive analysis of the oviraptorosaurs".Amongst her many publications are contributions to three chapters of the 2nd edition of the highly respected The Dinosauria: the chapters on the Therizinosauroidea, the Ankylosauria and on the Pachycephalosauria.As of 2004, she was affiliated with the Muzeum Ziemi of the Polska Akademia Nauk. She was assistant director of Muzeum Ziemi.

Texacephale

Texacephale is a genus of basal pachycephalosaurid dinosaur from the Campanian stage of the Late Cretaceous. The type species is Texacephale langstoni; its fossils were discovered in the Aguja Formation and 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.

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 estimated to have been about 1.4 metres (4.6 ft) in length. It had the tallest dome of any known pachycephalosaur.

Tylocephale lived during the Campanian stage, around 75 million years ago. It was discovered in the Khulsan region of Mongolia. The type species is T. gilmorei, described by Teresa Maryańska and Osmólska in 1974.The 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

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.