Chiayusaurus

Chiayusaurus Temporal range: ?Late Jurassic-?Early Cretaceous
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Superorder:	Dinosauria
Order:	Saurischia
Suborder:	Sauropodomorpha
Infraorder:	Sauropoda
(unranked):	Macronaria
Family:	Euhelopodidae?
Genus:	Chiayusaurus Bohlin, 1953
Species
C. lacustris type species  ?C. asianensis Lee, Yang, and Park, 1997

Chiayusaurus (meaning "Chia-yu-kuan lizard", after where it was found) was a genus of sauropod dinosaur known from teeth found in Asia. Two species have been named for this obscure genus. It was originally named as Chiayüsaurus, but the ICZN does not permit special characters, so it has become Chiayusaurus. The old name can still be seen in older sources, though.

History and taxonomy

Birger Bohlin based Chiayusaurus on a tooth crown in the IVPP. This tooth was found in the ?Tithonian-age ?Upper Jurassic Keilozo (now Kalazha) Formation of Xinjiang, China. This spatulate tooth crown was 27 millimeters long (1.1 inches), and was not unlike that of the younger genus Asiatosaurus.^[1] As it was based on such sparse material, it has largely been ignored or considered to be indistinguishable from other, better-known sauropods. For example, Russell and Zheng found its tooth to be indistinguishable from those of Mamenchisaurus.^[2]

Bohlin described a larger tooth in the 1953 publication as "Species A. (aff. Chiayüsaurus)", which he thought might belong to the type species.^[1] In 1997, Lee, Yang, and Park described a new species from South Korea based on a tooth (KPE 8001) which they regarded as being identical to "Species A. (aff. Chiayüsaurus)". This new species, C. asianensis, is from the Aptian-Albian-age Lower Cretaceous Hasandong Formation of Namdo, Gyeongsang. The authors rejected the suggestion that Bohlin's two teeth may have differed from being in different places in the jaw, and separated their species on the basis of details of the wear surfaces and placement of ridges. The C. asianensis tooth crown is 46 mm long (1.8 in).^[3]

Both species were reviewed in 2002, by Barrett et al. They regarded the type tooth of C. lacustris as nearly identical to teeth of Euhelopus, but were unable to conclusively establish synonymy, finding it to be an indeterminate eusauropod. They found that C. lacustris and C. asianensis shared no special features, and instead differed. C. asianensis was regarded as a possible titanosauriform, but still indeterminate.^[4] In the most recent review of sauropods, both species were considered to be dubious without comment.^[5]

Paleobiology

As a sauropod, Chiayusaurus would have been a large, quadrupedal herbivore.^[5]

References

1. ^ ^{a b} Bohlin, Birger (1953). "Fossil reptiles from Mongolia and Kansu". The Sino-Swedish Expedition Publication 37 (6): 1–113. 
2. ^ Russell, Dale A.; and Z. Zheng (1993). "A large mamenchisaurid from the Junggar Basin, Xinjiang, People's Republic of China.". Canadian Journal of Earth Sciences 30 (10–11): 2082–2095. doi:10.1139/e93-180. 
3. ^ Lee, Yuong-Nam; Seong-Young Yang; and Eun-Jun Park (1997). "Sauropod dinosaur remains from the Gyeongsang Supergroup Korea". Paleontological Society of Korea, Special Publication 2: 103–114. 
4. ^ Barrett, Paul M.; Yoshikazu Hasegawa; Makoto Manabe; Shinji Isaji; and Hiroshige Matsuoka (2002). "Sauropod dinosaurs from the Lower Cretaceous of eastern Asia: taxonomic and biogeographical implications". Palaeontology 45 (6): 1197–1217. doi:10.1111/1475-4983.00282. 
5. ^ ^{a b} Upchurch, Paul M.; Paul M. Barrett; and Peter Dodson (2004). "Sauropoda". In Weishampel, David B., Peter Dodson, and Halszka Osmólska (eds.). The Dinosauria (2nd edition). Berkeley: University of California Press. pp. 259–322. ISBN 0-520-24209-2. 

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