Neornithischia

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Neornithischians
Temporal range: Early JurassicLate Cretaceous, 199.6–66 Ma
Museum of the Rockies Dinosaur Heads.JPG
Skulls of neornithischian dinosaurs
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Order: Ornithischia
Clade: Genasauria
Clade: Neornithischia
Cooper, 1985
Subgroups

Neornithischia ("new ornithischians") is a clade of the dinosaur order Ornithischia. They are the sister group of the Thyreophora within the clade Genasauria. 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.

Life restoration of Othnielosaurus

Classification[edit]

Neornithischia was first named by Cooper in 1985 and defined as "all genasaurians more closely related to Parasaurolophus walkeri Parks, 1922, than to Ankylosaurus magniventris Brown, 1908 or Stegosaurus stenops Marsh, 1877a".[1] The cladogram below follows a 2011 analysis by paleontologists Richard J. Butler, Jin Liyong, Chen Jun and Pascal Godefroit.[2]

Neornithischia

Stormbergia




Agilisaurus




Hexinlusaurus




Othnielosaurus


Cerapoda

Ornithopoda



Marginocephalia







A recent study by Matthew G. Baron,[3] David B. Norman, and Paul M. Barrett recovered the Early Jurassic taxon Lesothosaurus diagnosticus from Southern Africa as the most basal known member of Neornithischia – a position previously held by Stormbergia dangershoeki (a taxon considered by the authors to be an adult form of Lesothosaurus and therefore a junior subjective synonym). However, Baron et 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. The cladogram below follows Baron et al. 2016.[4]

Neornithischia

Lesothosaurus




Agilisaurus Agilisaurus2.jpg




Hexinlusaurus




Othnielosaurus


Cerapoda

Ornithopoda Parasaurolophuspic steveoc.jpg



Marginocephalia Triceratops BW.jpg







References[edit]

  1. ^ Richard 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. 
  2. ^ Richard J. Butler; Jin Liyong; Chen Jun; Pascal Godefroit (2011). "The postcranial osteology and phylogenetic position of the small ornithischian dinosaur Changchunsaurus parvus from 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. 
  3. ^ Wade, Nicholas, Shaking Up the Dinosaur Family Tree, Science, March 22, 2017
  4. ^ Matthew G. Baron; David B. Norman; Paul M. Barrett (2016). "Postcranial anatomy of Lesothosaurus 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. 

External links[edit]