Yangchuanosaurus Temporal range: Bathonian to Berriasian, | |
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Y. shangyouensis skeleton displayed in Hong Kong Science Museum | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Family: | † Metriacanthosauridae |
Genus: | † Yangchuanosaurus Dong et al., 1978 |
Type species | |
†Yangchuanosaurus shangyouensis Dong et al., 1978 | |
Other species | |
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Synonyms | |
Synonyms of Y. shangyouensis
Synonyms of Y. zigongensis
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Yangchuanosaurus is an extinct genus of metriacanthosaurid theropod dinosaur that lived in China from the Middle Jurassic to Early Cretaceous periods (Bathonian to Berriasian stages), and was similar in size and appearance to its North American and European relative, Allosaurus . Yangchuanosaurus hails from the Upper Shaximiao Formation and Suining Formation and was the largest predator in a landscape that included the sauropods Mamenchisaurus and Omeisaurus and the stegosaurs Chialingosaurus , Tuojiangosaurus and Chungkingosaurus . This theropod was named after the area in which was discovered, Yongchuan, in China.
Dong et al. (1978) named Yangchuanosaurus shangyouensis on the basis of CV 00215, a complete skull and skeleton which was collected from the Shangshaximiao Formation, near Yongchuan, Yongchuan District, Sichuan. It dates to the Oxfordian stage of the Late Jurassic period, about 161.2 to 157.3 million years ago. It was discovered in June 1977 by a construction worker during the construction of the Shangyou Reservoir Dam. A second species from the same locality, Y. magnus, was named by Dong et al. (1983) on the basis of CV 00216, another complete skull and skeleton. A detailed revision of tetanuran phylogeny by Carrano, Benson & Sampson (2012) revealed that both species are conspecific. Dong et al. (1978) and Dong et al. (1983) differentiated these species primarily on the basis of size. In addition, Dong et al. (1983) noted that the maxilla of Y. magnus has an additional fenestra within the antorbital fossa, whereas Y. shangyouensis possessed only a fossa in this location. However, it is considered to be an intraspecific, possibly ontogenetic, variation. Furthermore, the apparent difference in cervical vertebral morphology can be explained by comparing different positions within the column. Hence, the holotypes of the two species of Yangchuanosaurus are effectively identical, and their codings are identical in Carrano et al. (2012) matrix. [1] Gregory S. Paul (1988) regarded this genus as a synonym of Metriacanthosaurus , but this has not been supported. [2]
Carrano et al. (2012) assigned a third specimen to Y. shangyouensis. CV 00214 is represented by a partial postcranial 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 . Later, Dong et al. (1983) described it, and assigned it to Szechuanosaurus campi, a dubious 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. A recent restudy of CV 00214 by Daniel Chure (2001) concluded that it represented a new taxon, informally named "Szechuanoraptor dongi", into which Szechuanosaurus zigongensis should also be subsumed. However, the most recent revision (by Carrano et al. (2012)) suggested that CV 00214 and "S." zigongensis cannot be cospecific as there are no autapomorphies 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 the second species of Yangchuanosaurus. [1]
Yangchuanosaurus 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. [3]
A third, informal species, Yangchuanosaurus "longqiaoensis", was briefly mentioned in a faunal listing of the Penglaizhen Formation (initially believed to date to the Late Jurassic but is probably Early Cretaceous (Berriasian – Valanginian) in age) [4] by Li, Zhang and Cai (1999). [5] 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. [6]
Remains assigned to Yangchuanosaurus sp. were recovered from the Berriasian Suining Formation in 1966. [7]
The type specimen of Y. shangyouensis had a skull 82 centimeters (2.69 ft) long, and its total body length was estimated at 8 meters (26 ft). [8] Another specimen, assigned to the new species Y. magnus, was even larger, with a skull length of 1.11 meters (3.6 ft). [9] It may have been up to 10.8 meters (35 ft) long, and weighed as much as 3.4 metric tons (3.7 short tons). [2] Gregory S. Paul suggested that these are the same species and gave a length of 11 meters (36 feet) and a weight of 3 metric tons (3.3 short tons). [10] There was a bony ridge on its nose and multiple hornlets and ridges, similar to Ceratosaurus .
Yangchuanosaurus was a large, powerful meat-eater. It walked on two large, muscular legs, had short arms, a strong, short neck, a big head with powerful jaws, and large, serrated teeth. 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.
A phylogenetic analysis by Carrano et al. (2012) found Yangchuanosaurus to be the basalmost known metriacanthosaurid and the only non-metriacanthosaurine metriacanthosaurid. The cladogram presented below follows their study. [1]
Orionides |
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The cladogram presented below follows Zanno & Makovicky (2013). [11]
Allosauroidea |
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Mamenchisaurus is a genus of sauropod dinosaur known for their remarkably long necks which made up nearly half the total body length. Numerous species have been assigned to the genus; however, many of these might be questionable. Fossils have been found in the Sichuan Basin and Yunnan Province in China. Several species are from the Upper Shaximiao Formation whose geologic age is uncertain. However, evidence suggests that this be no earlier than the Oxfordian stage of the Late Jurassic. M. sinocanadorum dates to the Oxfordian stage and M. anyuensis to the Aptian stage of the Early Cretaceous around 114.4 mya. Most species were medium to large size sauropods, around 15 to 26 meters in length and possibly up to 35 meters (115 ft) based on two undescribed vertebrae.
Gasosaurus is a genus of tetanuran theropod that lived approximately 171.6 to 161.2 million years ago during the middle of the Jurassic Period. The name "Gasosaurus" is derived from the English "gasoline" and the Greek σαῦρος. Only one species is currently recognised, G. constructus, from which the specific name honours the gasoline company that found the Dashanpu fossil quarry in Sichuan Province, China, now named as the Lower Shaximiao Formation.
Sinraptor is a genus of metriacanthosaurid theropod dinosaur from the Late Jurassic. The name Sinraptor comes from the Latin prefix "Sino", meaning Chinese, and "raptor" meaning robber. The specific name dongi honours Dong Zhiming. Despite its name, Sinraptor is not related to dromaeosaurids like Velociraptor. Instead, it was a carnosaur distantly related to Allosaurus. Sinraptor and its close relatives were among the earliest members of the Jurassic carnosaurian radiation. Sinraptor still remains the best-known member of the family Metriacanthosauridae, with some older sources even using the name "Sinraptoridae" for the family.
Abrosaurus is a genus of macronarian sauropod dinosaur from the Middle Jurassic Period of what is now Asia, one of many dinosaurs found at the Dashanpu Quarry in the Sichuan Province of China. Like most sauropods, Abrosaurus was a quadrupedal herbivore but it was rather small for a sauropod, not much more than 30 feet (9.1 m) long. Its head was boxy and topped with a tall bony arch containing the nostrils.
Xiaosaurus, is a genus of small herbivorous dinosaur from the middle Jurassic, approximately 169 to 163.5 mya. Xiaosaurus lived in what is now the Sichuan Basin of China.
Shunosaurus, meaning "Lizard from Sichuan", is a genus of sauropod dinosaur from Late Jurassic (Oxfordian) beds in Sichuan Province in China, from 161 to 157 Million years ago. The name derives from "Shu", an ancient name for the Sichuan province.
Huayangosaurus is a genus of stegosaurian dinosaur from the Middle Jurassic of China. The name derives from "Huayang" (華陽), an alternate name for Sichuan, and "saurus", meaning "lizard". It lived during the Bathonian to Callovian stages, around 165 million years ago, some 20 million years before its famous relative, Stegosaurus appeared in North America. At only approximately 4 metres (13 ft) long, it was also much smaller than its famous cousin. Found in the Lower Shaximiao Formation, Huayangosaurus shared the local Middle Jurassic landscape with the sauropods Shunosaurus, Datousaurus, Omeisaurus and Protognathosaurus, the ornithopod Xiaosaurus and the carnivorous Gasosaurus.
Xuanhanosaurus is a genus of theropod dinosaur that lived during the Middle Jurassic (Bathonian) of the Sichuan Basin, China, around 166.0 million years ago. This Taxon represents one of the various Carnosaurian taxa found on the Middle Jurassic of the region, uncovered on the Lower Shaximiao Formation. Although it has been known for more than 40 years, this taxon has been the subject of very few studies, although most seem to agree that it is a Tetanuran, possibly a basal Allosauroid, highlighting the fact that it has a vestigial fourth metacarpal.
Tuojiangosaurus is a genus of herbivorous stegosaurian dinosaur from the Late Jurassic Period, recovered from the Upper Shaximiao Formation of what is now Sichuan Province in China.
Zigongosaurus is a genus of sauropod dinosaur from the Middle Jurassic-Late Jurassic-age Shaximiao Formation of Zigong, Sichuan, China. Because of incomplete knowledge of Jurassic Chinese sauropods, it has been hard to interpret, with some sources assigning it to Omeisaurus, some to Mamenchisaurus, and some to its own genus.
Omeisaurus is a genus of sauropod dinosaur from the Middle Jurassic Period of what is now China. Its name comes from Mount Emei, where it was discovered in the lower Shaximiao Formation of Sichuan Province.
Sinosaurus is an extinct genus of theropod dinosaur which lived during the Early Jurassic Period. It was a bipedal carnivore approximately 5.5 metres (18 ft) in length and 300 kilograms (660 lb) in body mass. Fossils of the animal were found at the Lufeng Formation, in the Yunnan Province of China.
Szechuanosaurus 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. Its type species is based on several undiagnostic teeth from the Kuangyuan Series. Additional possible specimens of Szechuanosaurus were also reported from the Kalaza Formation, also located in China.
Chungkingosaurus, meaning "Chongqing Lizard", is a genus of herbivorous dinosaur from the Late Jurassic Upper Shaximiao Formation in what is now China. It is a member of the Stegosauria.
Metriacanthosauridae is an extinct family of allosauroid theropod dinosaurs that lived from the Middle Jurassic to the Early Cretaceous. When broken down into its Greek roots, it means "moderately-spined lizards". The family is split into two subgroups: Metriacanthosaurinae, which includes dinosaurs closely related to Metriacanthosaurus, and another group composed of the close relatives of Yangchuanosaurus. Metriacanthosaurids are considered carnosaurs, belonging to the Allosauroidea superfamily. The group includes species of large range in body size. Of their physical traits, most notable are their neural spines. The records of the group are mostly confined to Asia, though Metriacanthosaurus is known from Europe. Metriacanthosauridae is used as a senior synonym of Sinraptoridae.
Gigantspinosaurus is a genus of herbivorous ornithischian dinosaur from the Late Jurassic. It was a stegosaur found in China.
Hexinlusaurus is a genus of basal ornithischian dinosaur from the Middle Jurassic of China.
Dashanpusaurus is an extinct genus of sauropod dinosaur that lived during the middle of the Jurassic period. The dinosaur was described in 2005 by Peng Guangzhao, Ye Yong, Gao Yuhui, Shu Chunkang, and Jiang Shan. Its type and only species is Dashanpusaurus dongi, named in honor of the paleontologist Dong Zhiming.
The Shaximiao Formation is a Middle to Late Jurassic aged geological formation in Sichuan, China, most notable for the wealth of dinosaurs fossils that have been excavated from its strata. The Shaximiao Formation is exposed in and around the small township of Dashanpu, situated seven kilometres north-east from Sichuan's third largest city, Zigong, in the Da'an District.
Sunosuchus is an extinct genus of goniopholidid mesoeucrocodylian. Fossils are known from China, Kyrgyzstan, and Thailand and are Jurassic in age, although some may be Early Cretaceous. Four species are currently assigned to the genus: the type species S. miaoi and the species S. junggarensis, S. shartegensis, and S. shunanensis. All species are from China. Goniopholis phuwiangensis, also from Thailand, was reassigned to Sunosuchus by Andrade et al. (2011). The material from Kyrgyzstan has not been assigned to any species.