Szechuanosaurus Campi - IMG 1247

''Szechuanosaurus'' (" Szechuan lizard") is an extinct 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 Unpublished Ph.D. dissertation, Columbia University, New York genus of carnivorous theropod dinosaur from the Late Jurassic.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). Its type species is largely based on several undiagnostic teeth from the Shangshaximiao Formation and it is possibly also known from the Kuangyuan Series and the Kalaza Formation, both also located in China.

Discovery and species

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. 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''.Brusatte, 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.

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''. 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 campi'' 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. This individual was a medium-sized theropod, with an ischium (a pelvic bone) of ; for comparison, an ischium of ''Piatnitzkysaurus'' estimated to weigh is long. In 2000, Daniel Chure referred the specimen to "Szechuanoraptor dongi", itself an invalid ''nomen ex dissertatione''. 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.

Notes

References

''Szechuanosaurus campi'' in The Theropod Database

{{Taxonbar, from=Q637535

Fossil taxa described in 1942
Late Jurassic dinosaurs of Asia
Prehistoric neotheropods
Paleontology in Sichuan
Taxa named by Yang Zhongjian
Nomina dubia