Changchunsaurus

Unikonta

Changchunosaurus Temporal range: Early-Late Cretaceous, Aptian–Cenomanian PreЄ Є O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	Dinosauria
Order:	†Ornithischia
Node:	†Cerapoda
Suborder:	†Ornithopoda
Genus:	†Changchunsaurus Zan et al., 2005
Species:	†C. parvus
Binomial name
Changchunsaurus parvus Zan et al., 2005

Changchunsaurus (meaning "Changchun lizard") is an extinct genus of small herbivorous ornithopod dinosaur from Early Cretaceous deposits of Gongzhuling, Jilin, China. It is the first named dinosaur genus from Jilin.^[1]

Description

Changchunsaurus was first named by Zan Shu-Qin, Chen Jun, Jin Li-Yong and Li Tao in 2005. The type and only known species is C. parvus ("parvus" meaning "petite"), named for its small size. It is known from a skull and skeleton and additional skull fragments. All specimens of Changchunsaurus were collected from the Quantou Formation of the Songliao Basin, dating to the Aptian–Cenomanian stages. Changchunsaurus is based on the holotype JLUM L0403-j–Zn2, a skeleton and skull, with a premaxilla (upper beak) and partial lower jaw also known. Only the skull was figured and described in the official description.^[1]

According to Zan et al. 2005, who described it, the animal shows a combination of features like those of derived ornithopods (reduction in size or loss of some skull fenestrae or holes), and features like those of more basal ornithopods (for example, five teeth in each premaxilla, short toothless portion of upper beak, and a small gap between beak teeth and cheek teeth). There is a projection that sticks out from the side of the jugal or cheekbone, with what is described as a "nubble structure". The type individual was a small animal, around 1 meter long (3.3 feet, with a skull 11.5 centimeters long (4.5 inches). It was originally classified as a basal ornithopod, family unknown, although it was not included in a formal phylogenetic analysis.^[1]

Later, some referred specimens were described and in 2010 its cranial anatomy was revised.^[2] In Butler et al., 2011, the postcranial osteology was described for the first time and a latge phylogenetic analysis confirmed its position as a basal ornithopod which was found to be closely related to another Chinese ornithopod, Jeholosaurus^[3] and later to the newly described Chinese ornithopod Haya.^[4]

The following cladogram was based on analysis by Makovicky et al., 2011.^[4]

Neornithischia	Stormbergia Agilisaurus Hexinlusaurus Cerapoda Marginocephalia Ornithopoda Orodromeus Haya Changchunsaurus Jeholosaurus Hypsilophodon to Iguanodontia

Paleobiology

As a small basal ornithopod, Changchunsaurus would have been a swift bipedal herbivore, feeding close to the ground.^[5]

References

1. ^ ^{a b c} Zan Shu-Qin; Chen Jun; Jin Li-Yong; and Li Tao (2005). "A primitive ornithopod from the Early Cretaceous Quantou Formation of Central Jilin, China" (in Chinese with English summary). Vertebrata PalAsiatica 43 (3): 182–193. 
2. ^ Jin Liyong, Chen Jun, Zan Shu-Qin, Richard J. Butler and Pascal Godefroit (2010). "Cranial anatomy of the small ornithischian dinosaur Changchunsaurus parvus from the Quantou Formation (Cretaceous: Aptian–Cenomanian) of Jilin Province, northeastern China". Journal of Vertebrate Paleontology 30 (1): 196–214. doi:10.1080/02724630903412372. 
3. ^ 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. http://onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2011.01046.x/abstract. 
4. ^ ^{a b} Makovicky, Peter J.; Brandon M. Kilbourne, Rudyard W. Sadleir, and Mark A. Norell (2011). "A new basal ornithopod (Dinosauria, Ornithischia) from the Late Cretaceous of Mongolia". Journal of Vertebrate Paleontology 31 (3): 626–640. doi:10.1080/02724634.2011.557114. http://www.informaworld.com/smpp/content~db=all~content=a937433843~frm=titlelink. 
5. ^ Norman, David B.; Sues, Hans-Dieter; Witmer, Larry M.; and Coria, Rodolfo A. (2004). "Basal Ornithopoda". In Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 393–412. ISBN 0-520-24209-2. 

External links

• Changchunsaurus at Dinosaur.net.cn, with the article summary and photograph. (slow-loading)
• Changchunsaurus at Thescelosaurus! (under Ornithopoda i.s.).

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