Szechuanosaurus
{{Short description|Extinct genus of dinosaurs}}
{{Automatic taxobox
| fossil_range = Late Jurassic,
{{fossilrange|160|latest=145}}
| image = Szechuanosaurus campi tooth.jpg
| image_caption = Illustration of a partial tooth
| taxon = Szechuanosaurus
| authority = Young, 1942
| type_species = {{extinct}}Szechuanosaurus campi
| type_species_authority = Young, 1942
| synonyms =
}}
Szechuanosaurus ("Szechuan lizard") is an extinct genus of carnivorous theropod dinosaur from the Late Jurassic. Fossils referred to the genus have been found in China, Asia in the Oxfordian-?Tithonian (Peng et al., 2005).Peng, G.Z., Ye, Y., Gao, Y.H., Shu, C.K., Jiang, S. (2005): Jurassic dinosaur faunas in Zigong. Sichuan People’s Publishing
House, 236 pp Its type species is based on several undiagnostic teeth from the Kuangyuan Series."Table 4.1," in Weishampel, et al. (2004). Page 78. Additional possible specimens of Szechuanosaurus were also reported from the Kalaza Formation,"Table 13.1," in Weishampel, et al. (2004). Page 263. also located in China.
Szechuanosaurus is at times regarded as a nomen dubium{{Cite book |last=Sadleir |first=R. |url=https://books.google.com/books?id=N6JRAQAAIAAJ |title=The Anatomy and Systematics of Eustreptospondyllus Oxoniensis, a Theropod Dinosaur from the Middle Jurassic of Oxfordshire, England |date=2008 |publisher=Palaentographical Society |pages=61 |language=en}}{{Cite book |last1=Molina-Pérez |first1=Rubén |url=https://books.google.com/books?id=5m-KDwAAQBAJ |title=Dinosaur Facts and Figures: The Theropods and Other Dinosauriformes |last2=Larramendi |first2=Asier |last3=Connolly |first3=David |last4=Cruz |first4=Gonzalo Ángel Ramírez |date=2019 |publisher=Princeton University Press |isbn=978-0-691-18031-1 |pages=260 |language=en}} due to the lack of diagnostic features in the fossilized teeth upon which the genus is based.{{Cite book |last1=Weishampel |first1=David B. |url=https://books.google.com/books?id=vtZFDb_iw40C |title=The Dinosauria, Second Edition |last2=Dodson |first2=Peter |last3=Osmólska |first3=Halszka |date=2004 |publisher=University of California Press |isbn=978-0-520-94143-4 |pages=94 |language=en}} Although the fossils are too fragmentary for confident identification, Szechuanosaurus is often interpreted as a medium-sized allosaurid{{Cite book |last=Lucas |first=Spencer G. |url=https://books.google.com/books?id=AzHUXy7HGo4C |title=Chinese Fossil Vertebrates |date=2002 |publisher=Columbia University Press |isbn=978-0-231-50461-4 |pages=141–142 |language=en}} or perhaps a metriacanthosaurid, capable of reaching lengths of around 7.3 meters.
Discovery and species
File:Szechuanosaurus (9964979326).jpg]]
Three species have been assigned to this genus over the years. The type species is Szechuanosaurus campi, named by Yang Zhongjian ("Chung Chien Young") in 1942 for four isolated tooth specimens: IVPP V235, two partial teeth; IVPP V236, a partial tooth; IVPP V238, several tooth fragments; and IVPP V239, a single tooth. The teeth form a syntype series and were not found together. Also a very fragmentary skeleton, specimen UCMP 32102, was referred to the genus by Yang.Young, C.C., 1942, "Fossil vertebrates from Kuangyuan, N. Szechuan, China", Bulletin of the Geological Society of China, 22: 293-309 Some of the teeth indicate a large body-size. These fossils, although possibly metriacanthosaurid, are now considered to be non-diagnostic, making S. campi a nomen dubium.X.-C. Wu, P. J. Currie, Z. Dong, S. Pan, and T. Wang. 2009. A new theropod dinosaur from the Middle Jurassic of Lufeng, Yunnan, China. Acta Geologica Sinica 83(1):9-24Brusatte, S. L., Benson, R. B. J., and Xu, X. 2010. "The evolution of large-bodied theropod dinosaurs during the Mesozoic in Asia". Journal of Iberian Geology, 36: 275-296 The generic name refers to Szechuan. The specific name honours the American paleontologist Charles Lewis Camp who had discovered UCMP 32102.Camp, C.L., 1935, "Dinosaur remains from the Province of Szechuan", Bulletin of the Department of Geology of the Univiversity of California 23: 467-471
A partial skeleton, CV 00214, was initially listed by Dong et al. (1978) in a faunal list as a new species of Szechuanosaurus, Szechuanosaurus yandonensis.Dong, Z., Chang, Li & Zhou, 1978, "Note on a new carnosaur Yanchuangosaurus shangyuanensis gen. et sp. nov.) from the Jurassic of Yangchuan District, Szechuan Province", Kexue Tongabao 5: 302-304 At first, there was no description or illustration of it, making S. yandonensis at the time a nomen nudum. Later, Dong Zhiming et alii (1983) described it, and assigned it to Szechuanosaurus campiDong, Z-M., Zhou, S., Zhang, Y. (1983): [The dinosaurian remains of Sichuan Basin, China]. Palaeontologica Sinica (new series C), 23: 1–145 [in Chinese with English summary]. The affinities of this skeleton are uncertain, and it has only been briefly described. Holtz et al. (2004) included it in their phylogenetic analysis and found it to be the most basal tetanuran.Holtz, T.R., Molnar, R.E., Currie P.J. (2004): Basal Tetanurae. In: D.B. Weishampel, P. Dodson, P., H. Osmólska (ed.), The Dinosauria, 2nd edn. University of California Press, Berkeley, 71-110 This individual was a medium-sized theropod, with an ischium (a pelvic bone) of {{convert|420|mm|in}}; for comparison, an ischium of Piatnitzkysaurus estimated to weigh {{convert|504|kg|lb}} is {{convert|423|mm|in}} long. In 2000, Daniel Chure referred the specimen to "Szechuanoraptor dongi", itself an invalid nomen ex dissertatione.Chure, D.J. (2000) A new species of Allosaurus from the Morrison Formation of Dinosaur National Monument (UT–CO) and a revision of the theropod family Allosauridae. Unpublished Ph.D. dissertation, Columbia University, New York Carrano, Benson & Sampson (2012) synonymized it with Yangchuanosaurus shangyouensis from the same formation.
The third species is Szechuanosaurus zigongensis, named by Gao Yuhui in 1993 for an almost complete skeleton, specimen ZDM 9011.Gao, Y., 1993, "A new species of Szechuanosaurus from the Middle Jurassic of Dashanpu, Zigong, Sichuan", Vertebrata PalAsiatica 31(4): 308-314 It is an older species, from the Middle Jurassic, appearing to be distinct from the type species and therefore requires its own genus name. It was reassigned to Yangchuanosaurus, as a Yangchuanosaurus zigongensis, by Matthew Carrano, Roger Benson & Scott Sampson in 2012.{{Cite journal | last1 = Carrano | first1 = M. T. | last2 = Benson | first2 = R. B. J. | last3 = Sampson | first3 = S. D. | doi = 10.1080/14772019.2011.630927 | title = The phylogeny of Tetanurae (Dinosauria: Theropoda) | journal = Journal of Systematic Palaeontology | volume = 10 | issue = 2 | pages = 211–300| year = 2012 | bibcode = 2012JSPal..10..211C | s2cid = 85354215 }}
Notes
{{Reflist}}
References
- [https://web.archive.org/web/20130929081120/http://archosaur.us/theropoddatabase/Neotheropoda.htm#Szechuanosauruscampi Szechuanosaurus campi in The Theropod Database]
{{Portal|Dinosaurs}}
{{Theropoda|N.}}
{{Taxonbar|from=Q637535}}
Category:Taxa named by Yang Zhongjian