Prenocephale

The holotype specimen, Z. Pal. No. MgD-I/104, consists of an isolated yet well-preserved skull, dorsal vertebrae and ribs, sacrum, femora, and caudal vertebrae. It was discovered by the Polish-Mongolian Paleontological Expedition and was found at the Nemegt locality, in a sandstone layer of the Nemegt Formation. Additional specimens have been recovered from the Bügiin Tsav, Guriliin Tsav, and Tsaagan Khushuu localities of the formation.

File:Prenocephale Size Comparison.svg

Adult Prenocephale measured {{cvt|2.2|m|ft}} in length and {{cvt|40|kg|lbs}} in body mass.{{Cite book|last=Paul|first=Gregory S.|url=http://worldcat.org/oclc/985402380|title=The Princeton Field Guide to Dinosaurs|year=2016|publisher=Princeton University Press|isbn=978-1-78684-190-2|oclc=985402380|pages=269}} 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.{{cite book |editor=Palmer, D.|year=1999 |title= The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals|publisher= Marshall Editions|location=London|page= 137|isbn= 1-84028-152-9}}

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.

File:Prenocephale bickering (cropped + fix).jpg]]

File:Prenocephale 1.jpg

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. They all possess a distinct row of nodes on the squamosal and parietal areas of the skull roof.{{cite journal|author=Robert M. Sullivan|year=2003|title=Revision of the dinosaur Stegoceras Lambe (Ornithischia, Pachycephalosauridae)|journal=Journal of Vertebrate Paleontology |volume=23 |issue=1 |pages=181–207|doi=10.1671/0272-4634(2003)23[181:ROTDSL]2.0.CO;2|s2cid=85894105 }} However, Longrich et al. (2010) and Schott and Evans (2016) kept Sphaerotholus as a distinct genus based on cladistic analysis.{{cite journal|last1=Longrich|first1=Nicholas R.|last2=Sankey|first2=Julia|last3=Tanke|first3=Darren|year=2010|title=Texacephale langstoni, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA|journal=Cretaceous Research|volume=31|issue=2|pages=274–284|doi=10.1016/j.cretres.2009.12.002|bibcode=2010CrRes..31..274L }}{{cite mailing list |last=Headden |first=Jaime A. |url=http://dml.cmnh.org/2003Jan/msg00550.html |title=Re: Sphaerotholus |mailing-list=Dinosaur Mailing List |date=2003-01-25 |url-status=dead |archive-url=https://web.archive.org/web/20081202004920/http://dml.cmnh.org/2003Jan/msg00550.html |archive-date=2008-12-02}}

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.{{cite journal|last1=Evans |first1=David C. |last2=Hayashi |first2=Shoji |last3=Chiba |first3=Kentaro |last4=Watabe |first4=Mahito |last5=Ryan |first5=Michael J. |last6=Lee |first6=Yuong-Nam |last7=Currie |first7=Philip J. |last8=Tsogtbaatar |first8=Khishigjav |last9=Barsbold |first9=Rinchen |date=2018-04-01 |title=Morphology and histology of new cranial specimens of Pachycephalosauridae (Dinosauria: Ornithischia) from the Nemegt Formation, Mongolia |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=494 |pages=121–134 |doi=10.1016/j.palaeo.2017.11.029|bibcode=2018PPP...494..121E }}

Below is a cladogram modified from Evans et al., 2013.{{Cite journal | last1 = Evans | first1 = D. C. | last2 = Schott | first2 = R. K. | last3 = Larson | first3 = D. W. | last4 = Brown | first4 = C. M. | last5 = Ryan | first5 = M. J. | title = The oldest North American pachycephalosaurid and the hidden diversity of small-bodied ornithischian dinosaurs | doi = 10.1038/ncomms2749 | journal = Nature Communications | volume = 4 | pages = 1828 | year = 2013 | pmid = 23652016| bibcode = 2013NatCo...4.1828E | doi-access = free }}

{{clade| style=font-size:85%;line-height:85%

|label1=Pachycephalosauria

|1={{clade

|1=Wannanosaurus yansiensis

|label2=Pachycephalosauridae

|2={{clade

|1={{clade

|1=Colepiocephale lambei

|2=Hanssuesia sternbergi

|3=Stegoceras novomexicanum

|4=Stegoceras validum}}

|2={{clade

|1=Goyocephale lattimorei

|2={{clade

|1=Homalocephale calathocercos

|2={{clade

|1=Tylocephale gilmorei

|2={{clade

|1=Foraminacephale brevis

|2={{clade

|1=Amtocephale gobiensis

|2={{clade

|1={{clade

|1=Acrotholus audeti

|2=Prenocephale prenes}}

|2={{clade

|1={{clade

|1=Alaskacephale gangloffi

|2=Pachycephalosaurus wyomingensis}}

|2={{clade

|1=Sphaerotholus buchholtzae

|2=Sphaerotholus goodwini }} }} }} }} }} }} }} }} }} }} }}

Prenocephale lived in what is now the Nemegt Formation, in high upland forests, not the dry deserts of Mongolia nowadays.{{cite journal |last=Gradziński |first=Ryszard |year=1970 |title=Sedimentation of dinosaur-bearing Upper Cretaceous deposits of the Nemegt Basin, Gobi Desert |journal=Palaeontologia Polonica |volume=21 |pages=147–229 |url=http://www.palaeontologia.pan.pl/Archive/1969-21_147-232_35-42.pdf}}

{{Portal|Dinosaurs}}

• Timeline of pachycephalosaur research

{{Reflist}}

{{Pachycephalosauria|P.}}

{{Taxonbar|from=Q134220}}

Category:Pachycephalosauria

Category:Dinosaur genera

Category:Maastrichtian dinosaurs

Category:Nemegt Formation

Category:Taxa named by Teresa Maryańska

Category:Taxa named by Halszka Osmólska

Category:Fossil taxa described in 1974

Category:Dinosaurs of Mongolia