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{{Short description|Extinct genus of reptiles}}
{{Short description|Extinct genus of reptiles}}
{{speciesbox
{{speciesbox
| fossil_range = [[Early Cretaceous]], {{Fossil range|116|109}}
| fossil_range = [[Early Cretaceous]], {{Fossil range|98.2|93}}
| image = Cedarpelta price 1.jpg
| image = Cedarpelta price 1.jpg
| image_caption = Skull of ''Cedarpelta bilbeyhallorum'', on display at the [[USU Eastern Prehistoric Museum]], [[Price, Utah]]. The skull was reconstructed from two partial individuals excavated in 1997, and contains 70% of original fossil bone.
| image_caption = Skull of ''Cedarpelta bilbeyhallorum'', on display at the [[USU Eastern Prehistoric Museum]], [[Price, Utah]]. The skull was reconstructed from two partial individuals excavated in 1997, and contains 70% of original fossil bone.
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| authority = Carpenter ''et al.'', 2001
| authority = Carpenter ''et al.'', 2001
}}
}}
[[File:Cedarpelta price 2.jpg|thumb|Top view of the skull]]


'''''Cedarpelta''''' (meaning "[[Cedar Mountain Formation|Cedar Mountain]] shield") is a [[monospecific]] [[genus]] of basal [[ankylosauridae|ankylosaurid]] [[dinosaur]] from [[Utah]] that lived during the [[Early Cretaceous]] period ([[Cenomanian]] to lower [[Turonian]] stage, 98.2 to 93 Ma) in what is now the Mussentuchit Member of the [[Cedar Mountain Formation]]. The type and only species, '''''Cedarpelta bilbeyhallorum''''', is known from multiple specimens including partial [[skull|skulls]] and [[Postcrania|postcranial]] material. It was named in 2001 by [[Kenneth Carpenter]], [[James I. Kirkland|James Kirkland]], Don Burge, and John Bird. ''Cedarpelta'' has an estimated length of 7 metres (23 feet) and weight of 5 tonnes (11,023 lbs). The skull of ''Cedarpelta'' lacks extensive [[skull|cranial]] ornamentation and is one of the only known ankylosaurs with individual skull bones that are not completely fused together.
'''''Cedarpelta''''' is an [[extinct]] [[genus]] of herbivorous basal [[ankylosaurid]] [[ankylosaur]], based on material recovered from the Lower [[Cretaceous]] of [[North America]]. The skull lacks extensive [[cranium|cranial]] ornamentation, a trait which has been interpreted as [[plesiomorphic]] for ankylosaurs.


==Discovery==
==Discovery and naming==
[[File:Morrison-Cedar_Mtn-Naturita.jpg|thumb|left|Cedar Mountain Formation in Utah.]]
In 1990, Sue Ann Bilbey and Evan Hall discovered a quarry with the remains of ankylosaurs near the [[Price River]] in [[Carbon County, Utah|Carbon County]], [[Utah]]. In 1998, the discovery was reported in the scientific literature.<ref>Carpenter K., Kirkland J.I., 1998, "Review of Lower and middle Cretaceous ankylosaurs from North America", ''New Mexico Museum of Natural History and Science Bulletin'' '''14''': 249-270</ref> In 2001, the [[type species]] ''Cedarpelta bilbeyhallorum'' was named and described by [[Kenneth Carpenter]], [[James Kirkland (paleontologist)|James Kirkland]], [[Donald Burge]] and [[John Bird (paleontologist)|John Bird]]. The scientific name means "Bilbey and Hall's Cedar (Mountain) shield," with the [[genus]] named for the [[Cedar Mountain Formation]] and the animal's armored plates — from the Greek ''pelte'', "small shield" — and the [[specific name (zoology)|specific name]] honouring Sue Ann Bilbey and Evan Hall as the discoverers of the [[Type locality (geology)|type locality]].<ref name="Carpenter2001">Carpenter, K., Kirkland, J. I., Birge, D., and Bird, J. 2001. Disarticulated skull of a new primitive ankylosaurid from the Lower Cretaceous of Utah. in Carpenter, K. (editor) 2001. The Armored Dinosaurs. Indiana University Press</ref>
The partial remains of an [[ankylosauria|ankylosaur]] were discovered by Evan Hall and Sue Ann Bilbey at the CEM site near the [[Price River]] in [[Carbon County, Utah]] while they were visiting an excavation in the surrounding area.<ref name="Carpenter2001">Carpenter, K., Kirkland, J. I., Birge, D., and Bird, J. 2001. Disarticulated skull of a new primitive ankylosaurid from the Lower Cretaceous of Utah. in Carpenter, K. (editor) 2001. The Armored Dinosaurs. Indiana University Press</ref> The site was originally interpreted as being from the top of the Ruby Ranch Member of the [[Cedar Mountain Formation]]<ref name="Carpenter2001"/>, but was later interpreted as being from the bottom of the Mussentuchit Member.<ref name=KCetal08>{{cite journal|last=Carpenter|first=Kenneth|author-link=Kenneth Carpenter |author2=Bartlett, Jeff |author3=Bird, John |author4= Barrick, Reese |year=2008|title=Ankylosaurs from the Price River Quarries, Cedar Mountain Formation (Lower Cretaceous), east-central Utah |journal=Journal of Vertebrate Paleontology |volume=28 |issue=4 |pages=1089–1101|doi=10.1671/0272-4634-28.4.1089|s2cid=129480044}}</ref> The age of the layer was originally thought to have been 104.46 ± 0.95 Ma,<ref name="DCetal10">{{Cite journal|last=Chure|first=D.|author2=Britt|first2=B.|author3=Whitlock|first3=J.A.|author4=Wilson|first4=J.A.|year=2010|title=First complete sauropod dinosaur skull from the Cretaceous of the Americas and the evolution of sauropod dentition|journal=[[Naturwissenschaften]]|volume=97|issue=4|pages=379–391|doi=10.1007/s00114-010-0650-6|pmc=2841758|pmid=20179896}}</ref> but more recent estimates date it to 98.2 ± 0.6 to 93 Ma.<ref name=Avrahami2018>{{Cite journal|author1=Haviv M. Avrahami |author2=Terry A. Gates |author3=Andrew B. Heckert |author4=Peter J. Makovicky |author5= Lindsay E. Zanno |year=2018 |title=A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America |journal=PeerJ |volume=6 |pages=e5883 |doi=10.7717/peerj.5883 |pmc=6241397 |pmid=30479889}}</ref> In 1998, the discovery was reported by [[Kenneth Carpenter]] and [[James I. Kirkland|James Kirkland]].<ref name=Carpenter98>Carpenter K., Kirkland J.I., 1998, "Review of Lower and middle Cretaceous ankylosaurs from North America", ''New Mexico Museum of Natural History and Science Bulletin'' '''14''': 249-270</ref> In 2001, it was subsequently described, along with other material, by Kenneth Carpenter, James Kirkland, Don Burge, and John Bird. The holotype specimen, '''CEUM 12360''', consists of a partial [[skull]] that is missing the snout and [[mandible|lower jaws]]. Numerous [[osteoderm|osteoderms]], postcranial material and a disarticulated skull were designated as [[paratype]] specimens. Both holotype and paratype specimens represent at least three individuals and are currently housed at the [[USU Eastern Prehistoric Museum|College of Eastern Utah, Prehistoric Museum]], Utah.<ref name=Carpenter98/><ref name="Carpenter2001"/>


The generic name, ''Cedarpelta'', is derived from the Cedar Mountain Formation and the [[Ancient Greek|Greek]] word "''pelte''" (small shield). The specific name, ''bilbeyhallorum'', honours Sue Ann Bilbey and Evan Hall, who discovered the remains of ''Cedarpelta''.<ref name="Carpenter2001"/>
''Cedarpelta'' is known from remains recovered at the CEM and Price River II quarries (PR-2) in eastern Utah; these sites were originally thought to be within the [[Ruby Ranch Member]] of the Cedar Mountain Formation, but are now assigned to the base of the overlying [[Mussentuchit Member]], dating to between 116 and 109&nbsp;million years old (approximately the [[Aptian]]-[[Albian]] boundary).<ref name=KCetal08>{{cite journal|last=Carpenter|first=Kenneth |author-link=Kenneth Carpenter |author2=Bartlett, Jeff |author3=Bird, John |author4= Barrick, Reese |year=2008|title=Ankylosaurs from the Price River Quarries, Cedar Mountain Formation (Lower Cretaceous), east-central Utah |journal=Journal of Vertebrate Paleontology |volume=28 |issue=4 |pages=1089–1101 |doi=10.1671/0272-4634-28.4.1089|s2cid=129480044 }}</ref>


In 2008, additional specimens were referred to ''Cedarpelta'' from the Price River II Quarry, which is about 24.5 km southeast of Price River, Utah and at the base of the Mussentuchit Member. The quarry also produced specimens pertaining to four individuals of a [[brachiosauridae|brachiosaurid]], an [[Iguanodontia|iguanodontian]], a [[turtle]], a [[pterosaur]], and specimens of the [[nodosauridae|nodosaurid]] ''[[Peloroplites]]''. The referred material includes: CEUM 10396, a [[cervical vertebrae|cervical vertebra]]; CEUM 10412, CEUM 10404, caudal [[Vertebra|vertebrae]]; CEUM 10371, a [[coracoid]]; CEUM 10256, CEUM 11629, [[humerus|humeri]]; CEUM 10266, an [[ischium]]; CEUM 11334, a [[femur]]; and CEUM 11640, a [[tibia]].<ref name=KCetal08/>
=== Holotype ===
Carpenter ''et alii'' (2001) designated '''CEUM 12360''' as the [[holotype]] specimen of ''Cedarpelta bilbeyhallorum'' (CEUM is the [[acronym]] of the [[College of Eastern Utah Prehistoric Museum]] in Price, Utah). CEUM 12360 consists of an articulated, incomplete skull lacking the snout and mandibles. Carpenter ''et al.'' (2001) also designated a long list of [[paratype]] material, mostly isolated bones that could be referred to ''Cedarpelta bilbeyhallorum''.<ref name="Carpenter2001"/>

In 2008, Carpenter e.a. referred additional material found in [[Emery County]]. This includes previously unknown hindlimb elements.<ref name=KCetal08/>


== Description ==
== Description ==
''Cedarpelta'' was a large ankylosaurian. In 2010, [[Gregory S. Paul]] indicated a body length of 7 metres and a weight of 5 tonnes.<ref name="Paul2010">Paul, G.S., 2010, ''The Princeton Field Guide to Dinosaurs'', Princeton University Press p. 231</ref> [[Kenneth Carpenter]] estimated it smaller at 5 metres.<ref name=KCetal08/> [[Thomas R. Holtz Jr.|Thomas Holtz]] gave a higher estimation at 9 meters suggesting that it was rivaling ''[[Ankylosaurus]]''.<ref>{{Cite web|url=http://www.geol.umd.edu/~tholtz/dinoappendix/HoltzappendixWinter2011.pdf|title=Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages|last=Holtz|first=Thomas R.|date=2012}}</ref>
''Cedarpelta'' was a large ankylosaurian. In 2010, [[Gregory S. Paul]] indicated a body length of 7 metres and a weight of 5 tonnes.<ref name="Paul2010">Paul, G.S., 2010, ''The Princeton Field Guide to Dinosaurs'', Princeton University Press p. 231</ref> [[Kenneth Carpenter]] estimated it smaller at 5 metres.<ref name=KCetal08/> [[Thomas R. Holtz Jr.|Thomas Holtz]] gave a higher estimation at 9 meters suggesting that it was rivalling ''[[Ankylosaurus]]''.<ref>{{Cite web|url=http://www.geol.umd.edu/~tholtz/dinoappendix/HoltzappendixWinter2011.pdf|title=Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages|last=Holtz|first=Thomas R.|date=2012}}</ref>


Carpenter ''et al.'' (2001) established several distinguishing traits of ''Cedarpelta''. The body of the [[praemaxilla]], the front snout bone, is short in front of its nasal branch. The outer sides of the two praemaxillae run more parallel compared to the snouts of later forms which are strongly diverging to behind. The cutting edge of the bone core of the upper beak is limited to the front of the praemaxilla. Each praemaxilla has six (conical) [[tooth|teeth]]. The [[quadrate bone|quadrate]], and with it the entire back of the skull, is inclined to the front. The head of the quadrate is not fused with the paroccipital process, contrary to the situation in ''[[Shamosaurus]]''. The neck of the [[occipital condyle]] is long and sticking out to behind, like with nodosaurids, not obliquely to below as in typical ankylosaurids. The ''tubera basilaria'', appending processes of the rear lower braincase, form a large wedge directed to below. The [[Pterygoid bone|pterygoid]] is elongated from the front to the rear and has a saddle-shaped process on its outer edge oriented to behind and sideways. The coronoid process of the rear lower jaw has an oval process at the inside. The straight [[ischium]] has a knob-shaped boss at the inside near the pubic pedicle.<ref name="Carpenter2001"/>
Carpenter ''et al.'' (2001) established several distinguishing traits of ''Cedarpelta''. The body of the [[praemaxilla]], the front snout bone, is short in front of its nasal branch. The outer sides of the two praemaxillae run more parallel compared to the snouts of later forms which are strongly diverging to behind. The cutting edge of the bone core of the upper beak is limited to the front of the praemaxilla. Each praemaxilla has six (conical) [[tooth|teeth]]. The [[quadrate bone|quadrate]], and with it the entire back of the skull, is inclined to the front. The head of the quadrate is not fused with the paroccipital process, contrary to the situation in ''[[Shamosaurus]]''. The neck of the [[occipital condyle]] is long and sticking out to behind, like with nodosaurids, not obliquely to below as in typical ankylosaurids. The ''tubera basilaria'', appending processes of the rear lower braincase, form a large wedge directed to below. The [[Pterygoid bone|pterygoid]] is elongated from the front to the rear and has a saddle-shaped process on its outer edge oriented to behind and sideways. The coronoid process of the rear lower jaw has an oval process at the inside. The straight [[ischium]] has a knob-shaped boss at the inside near the pubic pedicle.<ref name="Carpenter2001"/>
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The skulls, though of large and thus not juvenile individuals, do not show a distinctive pattern of fused ''caputegulae'', head tiles. This inspired Carpenter to propose an alternative hypothesis of ankylosaur skull [[osteoderm]] formation. Formerly, it had been assumed that such armour plates were either formed by direct skin ossification into distinct scutes which later fused to the skull (the more popular theory), or by a reaction of the skull bones to the pattern of overlying scales. The lack of a clear pattern in ''Cedarpelta'' suggested to Carpenter that the ossification took place in an intermediate layer between the scales and the skull roof itself, which he surmised to have been the [[periosteum]].<ref name="Carpenter2001"/>
The skulls, though of large and thus not juvenile individuals, do not show a distinctive pattern of fused ''caputegulae'', head tiles. This inspired Carpenter to propose an alternative hypothesis of ankylosaur skull [[osteoderm]] formation. Formerly, it had been assumed that such armour plates were either formed by direct skin ossification into distinct scutes which later fused to the skull (the more popular theory), or by a reaction of the skull bones to the pattern of overlying scales. The lack of a clear pattern in ''Cedarpelta'' suggested to Carpenter that the ossification took place in an intermediate layer between the scales and the skull roof itself, which he surmised to have been the [[periosteum]].<ref name="Carpenter2001"/>


==Phylogenetics==
==Classification==
Carpenter (2001) placed ''Cedarpelta'' within the family [[Ankylosauridae]] and offered two interpretations of its position. The first was that it could be the basalmost known ankylosaurid, i.e. the first discovered branch to split off from the ankylosaurid stem line. This would be in line with its [[Plesiomorphy and symplesiomorphy|plesiomorphic]] traits and the fact that the in 2001 supposed [[Barremian]] age made it one of the oldest known ankylosaurids. The second was that it formed an early ankylosaurid branch, or clade, Shamosaurinae together with ''[[Gobisaurus]]'' of north-central [[China]] and the eponymous ''[[Shamosaurus]]'' of [[Mongolia]].<ref name="Carpenter01">Carpenter, K. 2001. Phylogenetic analysis of the Ankylosauria. in Carpenter, K. (editor) 2001. The Armored Dinosaurs. Indiana University Press</ref> Thompson et al. (2012),<ref name=Thompson2012>Richard S. Thompson, Jolyon C. Parish, Susannah C. R. Maidment and Paul M. Barrett, 2012, "Phylogeny of the ankylosaurian dinosaurs (Ornithischia: Thyreophora)", ''Journal of Systematic Palaeontology'' '''10'''(2): 301–312</ref> Chen et al. (2013),<ref name=Chen2013>{{Cite journal|author1=Rongjun Chen |author2=Wenjie Zheng |author3=Yoichi Azuma |author4=Masateru Shibata |author5=Tianliang Lou |author6=Qiang Jin |author7=Xingsheng Jin |year=2013 |title=A New Nodosaurid Ankylosaur from the Chaochuan Formation of Dongyang, Zhejiang Province, China |journal=Acta Geologica Sinica (English Edition) |volume=87 |issue=3 |pages=658–671 |url=http://www.geojournals.cn/dzxben/ch/reader/view_abstract.aspx?file_no=201303003&flag=1 |doi=10.1111/1755-6724.12077}}</ref> Yang et al. (2013),<ref name=yang2013>{{cite journal |author=Yang J.-T. |author2=You H.-L. |author3=Li D.-Q. |author4= Kong D.-L. |year=2013 |title=First discovery of polacanthine ankylosaur dinosaur in Asia |journal=Vertebrata PalAsiatica |volume=51 |issue=4 |pages=265–277 |language=Chinese, English |url=http://www.ivpp.cas.cn/cbw/gjzdwxb/xbwzxz/201312/P020131205318740255664.pdf}}</ref> Han et al. (2014),<ref>{{cite journal |author1=Han, F. |author2=Zheng, W. |author3=Hu, D. |author4=Xu, X. |author5=Barrett, P.M. |year=2014 |title=A New Basal Ankylosaurid (Dinosauria: Ornithischia) from the Lower Cretaceous Jiufotang Formation of Liaoning Province, China |journal=PLOS ONE |volume=9 |issue=8 |pages=e104551 |doi=10.1371/journal.pone.0104551 |pmid=25118986 |pmc=4131922|bibcode=2014PLoSO...9j4551H |doi-access=free }}</ref> Arbour & Currie (2015),<ref name="Arbour2015">{{cite journal|author1=Arbour, V. M. |author2=Currie, P. J. |year=2015|title=Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs|journal=Journal of Systematic Palaeontology|volume=14 |issue=5 |pages=1–60|doi=10.1080/14772019.2015.1059985|s2cid=214625754 }}</ref> Arbour et al. (2016),<ref name="arbour2016">{{cite journal|last=Arbour|first=V.M.|last2=Zanno|first2=L.E.|last3=Gates|first3=T.|year=2016|title=Ankylosaurian dinosaur palaeoenvironmental associations were influenced by extirpation, sea-level fluctuation, and geodispersal|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=449|pages=289-299|doi=10.1016/j.palaeo.2016.02.033}}</ref> Arbour & Evans (2017),<ref name="Arbour2017">{{cite journal|last1=Arbour|first1=Victoria M.|last2=Evans|first2=David C.|year=2017|title=A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation|journal=Royal Society Open Science|volume=4|issue=5|pages=161086|doi=10.1098/rsos.161086|pmid=28573004|bibcode=2017RSOS....461086A|pmc=5451805}}</ref> Yang et al. (2017),<ref>YANG Jingtao, YOU Hailu, XIE Li & ZHOU Hongrui, 2017, "A New Specimen of ''Crichtonpelta benxiensis'' (Dinosauria: Ankylosaurinae) from the Mid-Cretaceous of Liaoning Province, China", ''Acta Geologica Sinica'' '''91'''(3): 781-790</ref> Zheng et al. (2018),<ref name=WZ18>{{Cite journal|author1=Wenjie Zheng |author2=Xingsheng Jin |author3=Yoichi Azuma |author4=Qiongying Wang |author5=Kazunori Miyata |author6=Xing Xu |year=2018 |title=The most basal ankylosaurine dinosaur from the Albian–Cenomanian of China, with implications for the evolution of the tail club |journal=Scientific Reports |volume=8 |issue=1 |pages=Article number 3711 |doi=10.1038/s41598-018-21924-7 |pmc=5829254 |pmid=29487376 |bibcode=2018NatSR...8.3711Z }}</ref> Rivera-Sylva et al. (2018),<ref name="Rivera-Sylva2018">{{Cite journal|last1=Rivera-Sylva|first1=H.E.|last2=Frey|first2=E.|last3=Stinnesbeck|first3=W.|last4=Carbot-Chanona|first4=G.|last5=Sanchez-Uribe|first5=I.E.|last6=Guzmán-Gutiérrez|first6=J.R.|date=2018|title=Paleodiversity of Late Cretaceous Ankylosauria from Mexico and their phylogenetic significance|journal=Swiss Journal of Palaeontology|volume=137|issue=1|pages=83–93|doi=10.1007/s13358-018-0153-1|s2cid=134924657|issn=1664-2376}}</ref> Park et al. (2019)<ref name=Park2019>{{cite journal|last1=Park|first1=J. Y.|last2=Lee|first2=Y. N.|last3=Currie|first3=P. J.|last4=Kobayashi|first4=Y.|last5=Koppelhus|first5=E.|last6=Barsbold|first6=R.|last7=Mateus|first7=O.|last8=Lee|first8=S.|last9=Kim|first9=S. H.|title=Additional skulls of Talarurus plicatospineus (Dinosauria: Ankylosauridae) and implications for paleobiogeography and paleoecology of armored dinosaurs|date=2019|journal=Cretaceous Research|volume=108|page=104340|doi=10.1016/j.cretres.2019.104340|s2cid=212423361}}</ref> and Frauenfelder et al. (2022)<ref>{{Cite journal|last1=G. Frauenfelder|first1=Timothy|last2=R. Bell|first2=Phil|last3=Brougham|first3=Tom|last4=J. Bevitt|first4=Joseph|last5=D. C. Bicknell|first5=Russell|last6=P. Kear|first6=Benjamin|last7=Wroe|first7=Stephen|last8=E. Campione|first8=Nicolás|date=2022|title=New Ankylosaurian Cranial Remains From the Lower Cretaceous (Upper Albian) Toolebuc Formation of Queensland, Australia|journal=Frontiers in Earth Science|volume=10|pages=1–17|doi=10.3389/feart.2022.803505}}</ref> have all found ''Cedarpelta'' to be within Ankylosauridae, as either within a [[polytomy]] with ''[[Liaoningosaurus]]'', ''[[Aletopelta]]'', ''[[Chuanqilong]]'', ''Gobisaurus'' and ''Shamosaurus'' or as sister taxon to ''Chuanqilong''. The results of Arbour & Currie (2015) are reproduced below.
Carpenter ''et al.'' (2001) placed the [[taxon]] within the family [[Ankylosauridae]]. They offered two interpretations of the position of ''Cedarpelta bilbeyhallorum'' in the evolutionary tree. The first was that it could be the basalmost known ankylosaurid, i.e. the first discovered branch to split off from the ankylosaurid stem line. This would be in line with its plesiomorphic traits and the fact that the in 2001 supposed [[Barremian]] age made it one of the oldest known ankylosaurids. The second was that it formed an early ankylosaurid branch, or [[clade]], [[Shamosaurinae]] together with ''[[Gobisaurus]] domoculus'' of north-central [[China]] and the eponymous ''[[Shamosaurus]] scutatus'' of [[Mongolia]].<ref name="Carpenter2001"/>
{{clade| style=font-size:85%;line-height:85%

|label1=[[Ankylosauridae]]
Vickaryous ''et al.'' (2004), however, interpreted the genus as the basalmost member of the family [[Nodosauridae]], positioned even below the nodosaurids ''[[Pawpawsaurus]] campbelli'', ''[[Silvisaurus]] condrayi'', and ''[[Sauropelta]] edwardsorum''.<ref name=Vickaryous2014>Vickaryous M.K., [[Teresa Maryańska|Maryańska T.]], Weishampel D.B., 2004, "Ankylosauria". Chapter 17 in: Weishampel D.B., Dodson P., Osmólska H., editors. ''The Dinosauria''. 2nd ed. Berkeley (CA): University of California Press. p. 363–392</ref> However, new material of the skeleton confirms the original identification of Carpenter ''et al.'' of ''Cedarpelta'' being one of the most basal ankylosaurids.<ref name=KCetal08/> This was also a result of an analysis by [[Victoria Megan Arbour]] recovering ''Cedarpelta'' just above ''[[Gastonia (dinosaur)|Gastonia]]'', the most basal ankylosaurid in her study. No tail club of ''Cedarpelta'' is known, but Arbour stressed that early ankylosaurids might well have lacked a true club.<ref name="Arbour2014">Arbour, Victoria Megan, 2014. ''Systematics, evolution, and biogeography of the ankylosaurid dinosaurs''. Ph.D thesis, University of Alberta</ref>
|1={{clade
|1={{clade
|1=''[[Gastonia (dinosaur)|Gastonia]]''
|2=''[[Ahshislepelta]]'' }}
|3={{clade
|1=''[[Aletopelta]]''
|2=''[[Liaoningosaurus]]''
|4={{clade
|1='''''Cedarpelta'''''
|2=''[[Chuanqilong]]'' }}
|5={{clade
|1={{clade
|1=''[[Gobisaurus]]''
|2=''[[Shamosaurus]]'' }}
|2={{clade
|1=''[[Crichtonpelta]]''
|2={{clade
|1=''[[Tsagantegia]]''
|2=''"[[Zhejiangosaurus]]"''
|3={{clade
|1=''[[Pinacosaurus grangeri]]''
|2=''[[Pinacosaurus mephistocephalus]]'' }}
|4={{clade
|1={{clade
|1=''[[Saichania]]''
|2={{clade
|1=''[[Tarchia]]''
|2=''[[Zaraapelta]]'' }} }}
|2={{clade
|1=''[[Dyoplosaurus]]''
|2={{clade
|1={{clade
|1=''[[Talarurus]]''
|2=''[[Nodocephalosaurus]]'' }}
|2={{clade
|1={{clade
|1=''[[Ankylosaurus]]''
|2=''[[Anodontosaurus]]'' }}
|2=''[[Euoplocephalus]]''
|3={{clade
|1=''[[Scolosaurus]]''
|2=''[[Ziapelta]]'' }} }} }} }} }} }} }} }} }} }} }}
Vickaryous et al. (2004) interpreted ''Cedarpelta'' as the basalmost member of the family [[Nodosauridae]], positioned even below the nodosaurids ''[[Pawpawsaurus]]'', ''[[Silvisaurus]]'', and ''[[Sauropelta]]''.<ref name="vickaryousetal2004">Vickaryous, M. K., [[Teresa Maryańska|Maryanska, T.]], and Weishampel, D. B. (2004). Chapter Seventeen: Ankylosauria. in The Dinosauria (2nd edition), Weishampel, D. B., Dodson, P., and Osmólska, H., editors. University of California Press.</ref> Wiersma & Irmis (2018) also interpreted Cedarpelta as a nodosaurid.<ref name=wiersma2018>{{Cite journal|author1=Jelle P. Wiersma |author2=Randall B. Irmis |year=2018 |title=A new southern Laramidian ankylosaurid, ''Akainacephalus johnsoni'' gen. et sp. nov., from the upper Campanian Kaiparowits Formation of southern Utah, USA |journal=PeerJ |volume=6 |pages=e5016 |doi=10.7717/peerj.5016 |pmc=6063217 |pmid=30065856}}</ref> The results of Vickaryous et al. (2004) are reproduced below.
{{clade| style=font-size:85%;line-height:85%
|1={{clade
|1={{clade
|1=''[[Lesothosaurus|Lesothosaurus diagnosticus]]''
|2={{clade
|1=''[[Huayangosaurus|Huayangosaurus taibaii]]''
|2={{clade
|1={{clade
|1='''''Cedarpelta bilbeyhallorum'''''
|2=[[Nodosauridae]]}}
|2={{clade
|1=''[[Gargoyleosaurus|Gargoyleosaurus parkpinorum]]''
|2={{clade
|1=''[[Minmi|Minmi paravertebra]]''
|2={{clade
|1=''[[Gastonia (dinosaur)|Gastonia burgei]]''
|2={{clade
|1={{clade
|1=''[[Gobisaurus|Gobisaurus domoculus]]''
|2=''[[Shamosaurus|Shamosaurus scutatus]]''}}
|2={{clade
|1=''[[Tsagantegia|Tsagantegia longicranialis]]''
|2={{clade
|1=''[[Tarchia|Tarchia gigantea]]''
|2={{clade
|1={{clade
|1=''[[Ankylosaurus|Ankylosaurus magniventris]]''
|2=''[[Euoplocephalus|Euoplocephalus tutus]]''}}
|2={{clade
|1=''[[Saichania|Saichania chulsanensis]]''
|2=''[[Talarurus|Talarurus plicatospineus]]
|3={{clade
|1=''[[Pinacosaurus|Pinacosaurus grangeri]]''
|2={{clade
|1=''[[Pinacosaurus|Pinacosaurus mephistocephalus]]''
|2=''[[Tianzhenosaurus youngi]]''
}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}


==See also==
==See also==

Revision as of 11:18, 5 June 2022

Cedarpelta
Temporal range: Early Cretaceous, 98.2–93 Ma
Skull of Cedarpelta bilbeyhallorum, on display at the USU Eastern Prehistoric Museum, Price, Utah. The skull was reconstructed from two partial individuals excavated in 1997, and contains 70% of original fossil bone.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: †Ornithischia
Clade: †Thyreophora
Clade: †Ankylosauria
Family: †Ankylosauridae
Genus: †Cedarpelta
Carpenter et al., 2001
Species:
†C. bilbeyhallorum
Binomial name
†Cedarpelta bilbeyhallorum
Carpenter et al., 2001

Cedarpelta (meaning "Cedar Mountain shield") is a monospecific genus of basal ankylosaurid dinosaur from Utah that lived during the Early Cretaceous period (Cenomanian to lower Turonian stage, 98.2 to 93 Ma) in what is now the Mussentuchit Member of the Cedar Mountain Formation. The type and only species, Cedarpelta bilbeyhallorum, is known from multiple specimens including partial skulls and postcranial material. It was named in 2001 by Kenneth Carpenter, James Kirkland, Don Burge, and John Bird. Cedarpelta has an estimated length of 7 metres (23 feet) and weight of 5 tonnes (11,023 lbs). The skull of Cedarpelta lacks extensive cranial ornamentation and is one of the only known ankylosaurs with individual skull bones that are not completely fused together.

Discovery and naming

Cedar Mountain Formation in Utah.

The partial remains of an ankylosaur were discovered by Evan Hall and Sue Ann Bilbey at the CEM site near the Price River in Carbon County, Utah while they were visiting an excavation in the surrounding area.[1] The site was originally interpreted as being from the top of the Ruby Ranch Member of the Cedar Mountain Formation[1], but was later interpreted as being from the bottom of the Mussentuchit Member.[2] The age of the layer was originally thought to have been 104.46 ± 0.95 Ma,[3] but more recent estimates date it to 98.2 ± 0.6 to 93 Ma.[4] In 1998, the discovery was reported by Kenneth Carpenter and James Kirkland.[5] In 2001, it was subsequently described, along with other material, by Kenneth Carpenter, James Kirkland, Don Burge, and John Bird. The holotype specimen, CEUM 12360, consists of a partial skull that is missing the snout and lower jaws. Numerous osteoderms, postcranial material and a disarticulated skull were designated as paratype specimens. Both holotype and paratype specimens represent at least three individuals and are currently housed at the College of Eastern Utah, Prehistoric Museum, Utah.[5][1]

The generic name, Cedarpelta, is derived from the Cedar Mountain Formation and the Greek word "pelte" (small shield). The specific name, bilbeyhallorum, honours Sue Ann Bilbey and Evan Hall, who discovered the remains of Cedarpelta.[1]

In 2008, additional specimens were referred to Cedarpelta from the Price River II Quarry, which is about 24.5 km southeast of Price River, Utah and at the base of the Mussentuchit Member. The quarry also produced specimens pertaining to four individuals of a brachiosaurid, an iguanodontian, a turtle, a pterosaur, and specimens of the nodosaurid Peloroplites. The referred material includes: CEUM 10396, a cervical vertebra; CEUM 10412, CEUM 10404, caudal vertebrae; CEUM 10371, a coracoid; CEUM 10256, CEUM 11629, humeri; CEUM 10266, an ischium; CEUM 11334, a femur; and CEUM 11640, a tibia.[2]

Description

Cedarpelta was a large ankylosaurian. In 2010, Gregory S. Paul indicated a body length of 7 metres and a weight of 5 tonnes.[6] Kenneth Carpenter estimated it smaller at 5 metres.[2] Thomas Holtz gave a higher estimation at 9 meters suggesting that it was rivalling Ankylosaurus.[7]

Carpenter et al. (2001) established several distinguishing traits of Cedarpelta. The body of the praemaxilla, the front snout bone, is short in front of its nasal branch. The outer sides of the two praemaxillae run more parallel compared to the snouts of later forms which are strongly diverging to behind. The cutting edge of the bone core of the upper beak is limited to the front of the praemaxilla. Each praemaxilla has six (conical) teeth. The quadrate, and with it the entire back of the skull, is inclined to the front. The head of the quadrate is not fused with the paroccipital process, contrary to the situation in Shamosaurus. The neck of the occipital condyle is long and sticking out to behind, like with nodosaurids, not obliquely to below as in typical ankylosaurids. The tubera basilaria, appending processes of the rear lower braincase, form a large wedge directed to below. The pterygoid is elongated from the front to the rear and has a saddle-shaped process on its outer edge oriented to behind and sideways. The coronoid process of the rear lower jaw has an oval process at the inside. The straight ischium has a knob-shaped boss at the inside near the pubic pedicle.[1]

Cedarpelta shows a mix of basal ("primitive") and derived traits. The presence of premaxillary teeth is a plesiomorphic character because it is inherited from earlier Ornithischia. In contrast, closure of the opening on the side of the skull behind the orbit, the lateral temporal fenestra, is an advanced, derived (apomorphic) character only known in ankylosaurid ankylosaurians.[1]

Two skulls are known, and the skull length for Cedarpelta is estimated to have been roughly 60 centimetres (24 in). One of the Cedarpelta skulls was found disarticulated, a first for an ankylosaur skull, allowing paleontologists a unique opportunity to examine the individual bones instead of being limited to an ossified unit. The skull is relatively elongated and does not show a strongly appending beak. Of the conical premaxillary teeth, the first is the largest. The maxilla bears eighteen teeth. The eye socket is surrounded by the lacrimal, a single supraorbital and a large postorbital, excluding the prefrontal and the jugal from the orbital rim. The postcranial skeleton was in 2001 not described in any detail.[1]

The skulls, though of large and thus not juvenile individuals, do not show a distinctive pattern of fused caputegulae, head tiles. This inspired Carpenter to propose an alternative hypothesis of ankylosaur skull osteoderm formation. Formerly, it had been assumed that such armour plates were either formed by direct skin ossification into distinct scutes which later fused to the skull (the more popular theory), or by a reaction of the skull bones to the pattern of overlying scales. The lack of a clear pattern in Cedarpelta suggested to Carpenter that the ossification took place in an intermediate layer between the scales and the skull roof itself, which he surmised to have been the periosteum.[1]

Classification

Carpenter (2001) placed Cedarpelta within the family Ankylosauridae and offered two interpretations of its position. The first was that it could be the basalmost known ankylosaurid, i.e. the first discovered branch to split off from the ankylosaurid stem line. This would be in line with its plesiomorphic traits and the fact that the in 2001 supposed Barremian age made it one of the oldest known ankylosaurids. The second was that it formed an early ankylosaurid branch, or clade, Shamosaurinae together with Gobisaurus of north-central China and the eponymous Shamosaurus of Mongolia.[8] Thompson et al. (2012),[9] Chen et al. (2013),[10] Yang et al. (2013),[11] Han et al. (2014),[12] Arbour & Currie (2015),[13] Arbour et al. (2016),[14] Arbour & Evans (2017),[15] Yang et al. (2017),[16] Zheng et al. (2018),[17] Rivera-Sylva et al. (2018),[18] Park et al. (2019)[19] and Frauenfelder et al. (2022)[20] have all found Cedarpelta to be within Ankylosauridae, as either within a polytomy with Liaoningosaurus, Aletopelta, Chuanqilong, Gobisaurus and Shamosaurus or as sister taxon to Chuanqilong. The results of Arbour & Currie (2015) are reproduced below.

Ankylosauridae

Vickaryous et al. (2004) interpreted Cedarpelta as the basalmost member of the family Nodosauridae, positioned even below the nodosaurids Pawpawsaurus, Silvisaurus, and Sauropelta.[21] Wiersma & Irmis (2018) also interpreted Cedarpelta as a nodosaurid.[22] The results of Vickaryous et al. (2004) are reproduced below.

See also

References

  1. ^ a b c d e f g h Carpenter, K., Kirkland, J. I., Birge, D., and Bird, J. 2001. Disarticulated skull of a new primitive ankylosaurid from the Lower Cretaceous of Utah. in Carpenter, K. (editor) 2001. The Armored Dinosaurs. Indiana University Press
  2. ^ a b c Carpenter, Kenneth; Bartlett, Jeff; Bird, John; Barrick, Reese (2008). "Ankylosaurs from the Price River Quarries, Cedar Mountain Formation (Lower Cretaceous), east-central Utah". Journal of Vertebrate Paleontology. 28 (4): 1089–1101. doi:10.1671/0272-4634-28.4.1089. S2CID 129480044.
  3. ^ Chure, D.; Britt, B.; Whitlock, J.A.; Wilson, J.A. (2010). "First complete sauropod dinosaur skull from the Cretaceous of the Americas and the evolution of sauropod dentition". Naturwissenschaften. 97 (4): 379–391. doi:10.1007/s00114-010-0650-6. PMC 2841758. PMID 20179896.
  4. ^ Haviv M. Avrahami; Terry A. Gates; Andrew B. Heckert; Peter J. Makovicky; Lindsay E. Zanno (2018). "A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America". PeerJ. 6: e5883. doi:10.7717/peerj.5883. PMC 6241397. PMID 30479889.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  5. ^ a b Carpenter K., Kirkland J.I., 1998, "Review of Lower and middle Cretaceous ankylosaurs from North America", New Mexico Museum of Natural History and Science Bulletin 14: 249-270
  6. ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 231
  7. ^ Holtz, Thomas R. (2012). "Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages" (PDF).
  8. ^ Carpenter, K. 2001. Phylogenetic analysis of the Ankylosauria. in Carpenter, K. (editor) 2001. The Armored Dinosaurs. Indiana University Press
  9. ^ Richard S. Thompson, Jolyon C. Parish, Susannah C. R. Maidment and Paul M. Barrett, 2012, "Phylogeny of the ankylosaurian dinosaurs (Ornithischia: Thyreophora)", Journal of Systematic Palaeontology 10(2): 301–312
  10. ^ Rongjun Chen; Wenjie Zheng; Yoichi Azuma; Masateru Shibata; Tianliang Lou; Qiang Jin; Xingsheng Jin (2013). "A New Nodosaurid Ankylosaur from the Chaochuan Formation of Dongyang, Zhejiang Province, China". Acta Geologica Sinica (English Edition). 87 (3): 658–671. doi:10.1111/1755-6724.12077.
  11. ^ Yang J.-T.; You H.-L.; Li D.-Q.; Kong D.-L. (2013). "First discovery of polacanthine ankylosaur dinosaur in Asia" (PDF). Vertebrata PalAsiatica (in Chinese and English). 51 (4): 265–277.
  12. ^ Han, F.; Zheng, W.; Hu, D.; Xu, X.; Barrett, P.M. (2014). "A New Basal Ankylosaurid (Dinosauria: Ornithischia) from the Lower Cretaceous Jiufotang Formation of Liaoning Province, China". PLOS ONE. 9 (8): e104551. Bibcode:2014PLoSO...9j4551H. doi:10.1371/journal.pone.0104551. PMC 4131922. PMID 25118986.
  13. ^ Arbour, V. M.; Currie, P. J. (2015). "Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs". Journal of Systematic Palaeontology. 14 (5): 1–60. doi:10.1080/14772019.2015.1059985. S2CID 214625754.
  14. ^ Arbour, V.M.; Zanno, L.E.; Gates, T. (2016). "Ankylosaurian dinosaur palaeoenvironmental associations were influenced by extirpation, sea-level fluctuation, and geodispersal". Palaeogeography, Palaeoclimatology, Palaeoecology. 449: 289–299. doi:10.1016/j.palaeo.2016.02.033.
  15. ^ Arbour, Victoria M.; Evans, David C. (2017). "A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation". Royal Society Open Science. 4 (5): 161086. Bibcode:2017RSOS....461086A. doi:10.1098/rsos.161086. PMC 5451805. PMID 28573004.
  16. ^ YANG Jingtao, YOU Hailu, XIE Li & ZHOU Hongrui, 2017, "A New Specimen of Crichtonpelta benxiensis (Dinosauria: Ankylosaurinae) from the Mid-Cretaceous of Liaoning Province, China", Acta Geologica Sinica 91(3): 781-790
  17. ^ Wenjie Zheng; Xingsheng Jin; Yoichi Azuma; Qiongying Wang; Kazunori Miyata; Xing Xu (2018). "The most basal ankylosaurine dinosaur from the Albian–Cenomanian of China, with implications for the evolution of the tail club". Scientific Reports. 8 (1): Article number 3711. Bibcode:2018NatSR...8.3711Z. doi:10.1038/s41598-018-21924-7. PMC 5829254. PMID 29487376.
  18. ^ Rivera-Sylva, H.E.; Frey, E.; Stinnesbeck, W.; Carbot-Chanona, G.; Sanchez-Uribe, I.E.; Guzmán-Gutiérrez, J.R. (2018). "Paleodiversity of Late Cretaceous Ankylosauria from Mexico and their phylogenetic significance". Swiss Journal of Palaeontology. 137 (1): 83–93. doi:10.1007/s13358-018-0153-1. ISSN 1664-2376. S2CID 134924657.
  19. ^ Park, J. Y.; Lee, Y. N.; Currie, P. J.; Kobayashi, Y.; Koppelhus, E.; Barsbold, R.; Mateus, O.; Lee, S.; Kim, S. H. (2019). "Additional skulls of Talarurus plicatospineus (Dinosauria: Ankylosauridae) and implications for paleobiogeography and paleoecology of armored dinosaurs". Cretaceous Research. 108: 104340. doi:10.1016/j.cretres.2019.104340. S2CID 212423361.
  20. ^ G. Frauenfelder, Timothy; R. Bell, Phil; Brougham, Tom; J. Bevitt, Joseph; D. C. Bicknell, Russell; P. Kear, Benjamin; Wroe, Stephen; E. Campione, Nicolás (2022). "New Ankylosaurian Cranial Remains From the Lower Cretaceous (Upper Albian) Toolebuc Formation of Queensland, Australia". Frontiers in Earth Science. 10: 1–17. doi:10.3389/feart.2022.803505.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  21. ^ Vickaryous, M. K., Maryanska, T., and Weishampel, D. B. (2004). Chapter Seventeen: Ankylosauria. in The Dinosauria (2nd edition), Weishampel, D. B., Dodson, P., and Osmólska, H., editors. University of California Press.
  22. ^ Jelle P. Wiersma; Randall B. Irmis (2018). "A new southern Laramidian ankylosaurid, Akainacephalus johnsoni gen. et sp. nov., from the upper Campanian Kaiparowits Formation of southern Utah, USA". PeerJ. 6: e5016. doi:10.7717/peerj.5016. PMC 6063217. PMID 30065856.{{cite journal}}: CS1 maint: unflagged free DOI (link)
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