Yangchuanosaurus

 ( Metriacanthosauridae ) 

Carrano et al. (2012) assigned a third specimen to Y. shangyouensis. CV 00214 is represented by a partial skeleton lacking the skull. It was collected in the Wujiaba Quarry, near Zigong city, Sichuan, from the lower part of the Shangshaximiao Formation. CV 00214 was initially listed by Dong et al. (1978) in a faunal list as a new species of Szechuanosaurus, Szechuanosaurus "yandonensis". There is no description or illustration of it, making S. "yandonensis" a nomen nudum. Paul (1988) listed CV 00214 as Metriacanthosaurus? sp., but earlier in his discussion of the genus, uses the name M. carpenteri. Regardless, under ICZN Article 11.5, the name Metriacanthosaurus "carpenteri" is a nomen nudum, and its inclusion is likely a typographical error. Later, Dong et al. (1983) described it, and assigned it to Szechuanosaurus campi, a nomen dubium species which is known only from four teeth. Carrano et al. (2012) noted that CV 00214 can't be assigned to S. campi because the holotype materials of S. campi (IVPP V.235, V.236, V.238, V.239; teeth) are non-diagnostic and no teeth are preserved in CV 00214. In his doctoral dissertation, Chure (2000) restudied CV 00214 and concluded that it represented a new taxon, which he informally named "Szechuanoraptor dongi", into which Szechuanosaurus zigongensis should also be subsumed.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. Doctoral dissertation, Columbia University. However, Carrano et al. (2012) suggested that CV 00214 and " S." zigongensis cannot be cospecific as there are no autapomorphy shared between them, and the latter derives from the underlying Xiashaximiao Formation. A phylogenetic analysis found CV 00214 to be most closely related to Y. shangyouensis, and thus the former is assignable to it. Furthermore, Szechuanosaurus zigongensis was found to be closely related to Y. shangyouensis and therefore was designated as a new species of Yangchuanosaurus, though this has been considered questionable by Rauhut and colleagues.

Y.? zigongensis is known from four specimens including ZDM 9011 (holotype), a partial postcranial skeleton; ZDM 9012, a left maxilla; ZDM 9013, two teeth and ZDM 9014, a right hind limb. It was first described by Gao (1993), and all specimens were collected from the Middle Jurassic Xiashaximiao Formation in the Dashanpu Dinosaur Quarry of Zigong, Sichuan.Gao, Y. (1993). A new species of Szechuanosaurus from the Middle Jurassic of Dashanpu, Zigong, Sichuan . Vertebrata PalAsiatica 31(4): 308-314.

The informal species, Y. "longqiaoensis", was briefly mentioned in a faunal listing of the Penglaizhen Formation (initially believed to date to the Late Jurassic but may be Early Cretaceous (Berriasian-Valanginian) in age) by Li, Zhang and Cai (1999). However, since it was published solely in a faunal list and not described in detail, it is a nomen nudum and is questionably referable to Yangchuanosaurus.

Yangchuanosaurus was a large, powerful carnivore. It bipedalism large, muscular legs, had short arms, a strong, short neck, a big head with powerful jaws, and large, Serration. It had a long, massive tail that was about half of its length. The first digit of its foot was a small dewclaw. The three outer toes were used to bear weight and each was equipped with a large claw.