Szechuanosaurus

Eukaryota

Szechuanosaurus Temporal range: Late Jurassic, 150 Ma PreЄ Є O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	Dinosauria
Order:	Saurischia
Suborder:	Theropoda
Node:	Neotheropoda
Genus:	†Szechuanosaurus Young, 1942
Species
S. campi Young, 1942 (type)  ?S. zigongensis Gao, 1993

Szechuanosaurus ("Szechuan lizard") is a dubious^[1] genus of theropod dinosaur from the Late Jurassic. This dinosaur lived in the Asia in the Oxfordian and early Kimmeridgian (Peng et al., 2005).^[2] It is based on four undiagnostic teeth from the Shangshaximiao Formation.

Discovery and species

Three species have been assigned to this genus over the years. The type species is S. campi, named by Chung Chien Young in 1942 for four isolated teeth; these fossils are now considered to be nondiagnostic.^[3] Dong et al. (1983) assigned a partial skeleton to this species.^[4] 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.^[5] This individual was a medium-sized theropod, with an ischium (a pelvic bone) of 420 millimetres (17 in); for comparison, an ischium of Piatnitzkysaurus estimated to weigh 504 kilograms (1,110 lb) is 423 millimetres (16.7 in) long.^[3] S. campi is sometimes reported to includes S. yandonensis (named by Dong, Chang, Li and Zhou in 1978) and Chienkosaurus ceratosauroides, although some researchers still believe that the latter may yet prove to be a distinct species. Third species S. zigongensis (named by Gao in 1993 for an almost complete skeleton) is an older species, from the Middle Jurassic, appears to be distinct from the type species and therefore requires its own genus name.^[3] In any case, also the partial skeleton by Dong et al. (1983) deserves its own genus.

References

• Szechuanosaurus in The Dinosaur Encyclopaedia at Dino Russ's Lair
• Szechuanosaurus campi in The Theropod Database

1. ^ 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 Unpublished Ph.D. dissertation, Columbia University, New York.
2. ^ 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.
3. ^ ^{a b c} 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.
4. ^ Dong, 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].
5. ^ 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.

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