Prenocephale

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Prenocephale
Temporal range: Late Cretaceous, 71–68 Ma
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Prenocephale prenes.JPG
Cast of a P. prenes skull
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: †Ornithischia
Suborder: †Pachycephalosauria
Family: †Pachycephalosauridae
Genus: †Prenocephale
Maryańska & Osmólska, 1974
Species
  • †P. prenes Maryńska & Osmólska, 1974 (type)
Synonyms

Prenocephale (meaning "sloping head"[1]) was a small pachycephalosaurid dinosaur genus from the Late Cretaceous (Maastrichtian) of Mongolia and was similar in many ways to its close relative, Homalocephale, which may simply represent Prenocephale juveniles.

Description[]

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 the Nemegt Formation, in high upland forests, not the dry deserts of Mongolia today.[2]

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.[3][4][5]

Classification[]

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.[6] 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.[7]

 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[]

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. ^ "Prenocephale | Natural History Museum".
  2. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 137. ISBN 1-84028-152-9.
  3. ^ 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
  4. ^ Re: Sphaerotholus
  5. ^ 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.
  6. ^ Robert M. Sullivan (2003). "Revision of the dinosaur Stegoceras Lambe (Ornithischia, Pachycephalosauridae)". Journal of Vertebrate Paleontology. 23 (1): 181–207. doi:10.1671/0272-4634(2003)23[181:ROTDSL]2.0.CO;2.
  7. ^ 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...4.1828E. doi:10.1038/ncomms2749. PMID 23652016.

External links[]

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