Neornithischia
| Neornithischians | |
|---|---|
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| Six neornithischians (top left to bottom right):Psittacosaurus,Styracosaurus,Thescelosaurus,Kulindadromeus,Hypacrosaurus,Pachycephalosaurus | |
Scientific classification
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | †Ornithischia |
| Clade: | †Genasauria |
| Clade: | †Neornithischia Cooper, 1985 |
| Subgroups[1] | |
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Neornithischia( "new ornithischians" ) is acladeof thedinosaurorderOrnithischia.It is the sister group of theThyreophorawithin the cladeGenasauria.Neornithischians are united by having a thicker layer of asymmetrical enamel on the inside of their lower teeth. The teeth wore unevenly with chewing and developed sharp ridges that allowed neornithischians to break down tougher plant food than other dinosaurs.
Neornithischians include a variety of basal forms historically known as "hypsilophodonts",including theThescelosauridae.As these taxa do not all form amonophyleticclade, the term 'small-bodied early diverging ornithischian' (SBEDO) has been used to refer to these as a collective group.[2]In addition, there are derived forms classified in the groupsMarginocephaliaandOrnithopoda.The former includes cladesPachycephalosauriaandCeratopsia,while the latter typically includesHypsilophodonand the more derivedIguanodontia.
Classification
[edit]Neornithischia was first named by Cooper in 1985 and defined as "all genasaurians more closely related toParasaurolophus walkerithan toAnkylosaurus magniventrisorStegosaurus stenops".[3]In 2021, Neornithischia was given a formal definition under thePhyloCode:"The largest clade containingIguanodon bernissartensisandTriceratops horridusbut notAnkylosaurus magniventrisandStegosaurus stenops."[4]
A 2017 study by Matthew G. Baron,David B. Norman,and Paul M. Barrett recovered the Early Jurassic taxonLesothosaurus diagnosticusfrom Southern Africa as the most basal known member of Neornithischia – a position previously held byStormbergia dangershoeki(a taxon considered by the authors to be an adult form ofLesothosaurusand therefore a junior subjective synonym). However, Baronet al.go on to state that this result is only poorly supported and that future studies will be needed in order to better resolve the base of the ornithischian tree.[5]
Cerapodais the most diverse clade within Neornithischia. The name "Cerapoda" is a portmanteaux of "Ceratopsia" and "Ornithopoda". As the name suggests, the clade is divided into two groups:Ornithopoda( "bird-foot" ) andMarginocephalia( "fringed heads" ). The latter group includes thePachycephalosauria( "thick-headed lizards" ) andCeratopsia( "horned faces" ). The following taxonomy followsRichard J. Butler,Paul Upchurch andDavid B. Norman,2008 (and Butleret al.,2011) unless otherwise noted.[3][6]
Cerapoda was first named bySerenoin 1986 and defined by him as "Parasaurolophus walkeriParks, 1922,Triceratops horridusMarsh, 1889, their most recent common ancestor and all descendants ".[3]A similar clade Neornithopoda was tentatively proposed byDavid B. Normanto unite ceratopsians with advanced ornithopods in a 1984 paper.[7]In 2021, Cerapoda was given a formal definition under thePhyloCode:"The smallest clade containingIguanodon bernissartensisBoulenger in Beneden, 1881,Pachycephalosaurus wyomingensis(Gilmore, 1931), andTriceratops horridusMarsh, 1889. "[4]
The phylogenetic study of Fonseca and colleagues in 2024 recovered results similar to the previous analyses of Boyd and Herne and colleagues,[8][9]with thescelosaurids outside Ornithopoda and heterodontosaurids outside Neornithischia, while other aspects of relationships, like the placement ofChangmianiaor the grouping within Ornithopoda were novel results. Their equal-weights results are below.[1]
| Ornithischia |
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References
[edit]- ^abcFonseca, A.O.; Reid, I.J.; Venner, A.; Duncan, R.J.; Garcia, M.S.; Müller, R.T. (2024). "A comprehensive phylogenetic analysis on early ornithischian evolution".Journal of Systematic Palaeontology.22(1): 2346577.doi:10.1080/14772019.2024.2346577.
- ^Avrahami, Haviv M.; Makovicky, Peter J.; Tucker, Ryan T.; Zanno, Lindsay E. (2024-07-09)."A new semi-fossorial thescelosaurine dinosaur from the Cenomanian-age Mussentuchit Member of the Cedar Mountain Formation, Utah".The Anatomical Record.doi:10.1002/ar.25505.ISSN1932-8486.PMID38979930.
- ^abcRichard J. Butler; Paul Upchurch; David B. Norman (2008). "The phylogeny of the ornithischian dinosaurs".Journal of Systematic Palaeontology.6(1): 1–40.doi:10.1017/S1477201907002271.S2CID86728076.
- ^abMadzia D, Arbour VM, Boyd CA, Farke AA, Cruzado-Caballero P, Evans DC. 2021. The phylogenetic nomenclature of ornithischian dinosaurs.PeerJ9:e12362[1]
- ^Matthew G. Baron; David B. Norman; Paul M. Barrett (2016)."Postcranial anatomy ofLesothosaurus diagnosticus(Dinosauria: Ornithischia) from the Lower Jurassic of southern Africa: implications for basal ornithischian taxonomy and systematics ".Zoological Journal of the Linnean Society.doi:10.1111/zoj.12434.
- ^Richard J. Butler; Jin Liyong; Chen Jun; Pascal Godefroit (2011). "The postcranial osteology and phylogenetic position of the small ornithischian dinosaurChangchunsaurus parvusfrom the Quantou Formation (Cretaceous: Aptian–Cenomanian) of Jilin Province, north-eastern China ".Palaeontology.54(3): 667–683.doi:10.1111/j.1475-4983.2011.01046.x.
- ^Norman, D.B. (1984). "A systematic reappraisal of the reptile order Ornithischia". In Reif, W.E.; Westphal, F. (eds.).Third Symposium on Mesozoic Terrestrial Ecosystems, Short Papers.ATTEMPTO Verlag. pp. 157–162.
- ^Clint A. Boyd (2015)."The systematic relationships and biogeographic history of ornithischian dinosaurs".PeerJ.3(e1523): e1523.doi:10.7717/peerj.1523.PMC4690359.PMID26713260.
- ^Herne, Matthew C.; Nair, Jay P.; Evans, Alistair R.; Tait, Alan M. (2019)."New small-bodied ornithopods (Dinosauria, Neornithischia) from the Early Cretaceous Wonthaggi Formation (Strzelecki Group) of the Australian-Antarctic rift system, with revision of Qantassaurus intrepidus Rich and Vickers-Rich, 1999".Journal of Paleontology.93(3): 543–584.doi:10.1017/jpa.2018.95.
- Butler, R.J. (2005)."The 'fabrosaurid' ornithischian dinosaurs of the Upper Elliot Formation (Lower Jurassic) of South Africa and Lesotho".Zoological Journal of the Linnean Society.145(2): 175-18.doi:10.1111/j.1096-3642.2005.00182.x.
- Sereno, P.C.(1986). "Phylogeny of the bird-hipped dinosaurs (order Ornithischia)".National Geographic Research.2(2): 234–56.
External links
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