Shunosaurus

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Shunosaurus
Temporal range: Late Jurassic (Oxfordian), 161–157  Ma
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Shunosaurus - Finnish Museum of Natural History.jpg
Mount in the Finnish Museum of Natural History
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade:† Sauropodomorpha
Clade:† Sauropoda
Clade:† Eusauropoda
Genus:† Shunosaurus
Dong et al., 1983
Type species
†Shunosaurus lii
Dong et al., 1983
Other species
  • †Shunosaurus jiangyiensis
    Fu & Zhang, 2004

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. [1] The name derives from "Shu", an ancient name for the Sichuan province.

Contents

Discovery and species

Skeletal cast mount, Tianjin Natural History Museum Shunosaurus-Tianjin Natural History Museum.jpg
Skeletal cast mount, Tianjin Natural History Museum
Skeletons of Shunosaurus (left) and Giganotosaurus (right) in the Natural History Museum of Helsinki, Finland Museum of Natural History Helsinki.jpg
Skeletons of Shunosaurus (left) and Giganotosaurus (right) in the Natural History Museum of Helsinki, Finland

The first fossil of Shunosaurus was discovered in 1977 by a group of students, practising paleontological excavation at a road bank. The type species, Shunosaurus lii, was described and named by Dong Zhiming, Zhou Shiwu and Zhang Yihong in 1983. The generic name derives from "Shu", an ancient name for Sichuan. The specific name honours hydrologist Li Bing, the governor of Sichuan in the third century BC. [2]

The holotype, IVPP V.9065, was collected from the Lower Xiashaximiao Formation near Dashanpu, Zigong. It consists of a partial skeleton. Later about twenty more major specimens were discovered, including several complete or near-complete skeletons, skulls and juveniles, [3] making Shunosaurus one of the best anatomically known sauropods, with 94% of all skeletal elements identified. Shunosaurus skeletons are on display at the Zigong Dinosaur Museum in Zigong, Sichuan Province, and the Tianjin Natural History Museum.

A proposed second species, S. ziliujingensis, a name mentioned in the Zigong museum guide to indicate a smaller and older form, has never been formally described, and thus remains a nomen nudum .

In 2004 a partial semi-articulated specimen from Jiangyi Township in Yuanmou County was described as the new species Shunosaurus jiangyiensis. It is known from nine cervicals, 15 dorsals, three sacrals, four caudals, both scapulae, the right coracoid and clavicle, the right forelimb lacking the hand, a pubis and ischium and the right hindlimb, found in the upper section of the Middle Jurassic Xiashaximiao Formation. The species was separated from Shunosaurus lii based on its unique pectoral girdle, but was described as otherwise very similar to both Shunosaurus lii and Kunmingosaurus . [4]

Description

Shunosaurus was first estimated to be 11 metres (36 ft) long; later and more complete finds indicated a somewhat smaller size. In 2010 Gregory S. Paul estimated the length at 9.5 metres (31 ft), the weight at 3 metric tons (3.3 short tons). [5] Shunosaurus was very short-necked for a sauropod, being only "surpassed"[ clarification needed ] in this respect by Brachytrachelopan . [6] The skulls found are mostly compressed or disarticulated and the interpretation of the head form has varied from broad, short and deep [7] to extremely narrow and pointed. [8] The upper and lower jaws were strongly curved upwards, allowing them to function as a pair of garden shears. The teeth were fairly robust but elongated with a crown length of up to 8 centimetres (3.1 in). They show a unique combination of a cylindrical body ending in a spatulate tip. Published in 1989 was the discovery that the tail ended in a club, [9] equipped on its top with two successive spikes formed by cone-shaped osteoderms with a length of 5 centimetres (2.0 in). The club was probably used to fend off predators.

Classification

Size comparison Shunosaurus Scale.svg
Size comparison

Shunosaurus was originally classified as a member of the Cetiosaurinae; in 1992 Dong assigned it to Shunosaurinae within the Cetiosauridae. [10]

Cladistic analyses have rendered conflicting results. In 1995 Paul Upchurch published a study in which Shunosaurus belonged to the Euhelopodidae together with other Jurassic Chinese sauropods. [11] However, an analysis by Jeffrey Wilson in 2002 indicated it had a very basal position within the Eusauropoda. [12] Shunosaurus is perhaps related to Rhoetosaurus from Queensland in Australia.

Paleobiology

Tail-club Zigong Dinosaur Museum Shunosaurus tail club.jpg
Tail-club

Its neck length indicates that Shunosaurus was a low browser. The form of its jaws is well-adapted to processing large amounts of coarse plant material. [13]

Shunosaurus accounts for 90% of the fossils found in the Dashanpu fauna, showing it was a dominant and/ or common member of its habitat and environment. It shared the local Middle Jurassic landscape with other sauropods, Datousaurus , Omeisaurus and Protognathosaurus , the possible ornithopod Xiaosaurus , and the early stegosaur Huayangosaurus , as well as the carnivorous theropod Gasosaurus .

Related Research Articles

<i>Mamenchisaurus</i> Sauropod dinosaur genus from Late Jurassic-Early Cretaceous Period

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, the validity of these assignments has been questioned. Fossils have been found in the Sichuan Basin and Yunnan Province in China. Several species from the Upper Shaximiao Formation, whose geologic age is uncertain, have been described. However, evidence suggests this formation to 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. Most species were medium-large to large sauropods, measuring roughly 15 to 26 meters in length—possibly up to 35 meters (115 ft), based on two undescribed vertebrae.

<i>Yangchuanosaurus</i> Metriacanthosaurid theropod dinosaur genus from Middle Jurassic period.

Yangchuanosaurus is an extinct genus of metriacanthosaurid theropod dinosaur that lived in China from the Middle Jurassic to Early Cretaceous periods, 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.

<i>Abrosaurus</i> Extinct genus of reptiles

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.

<i>Yandusaurus</i> Extinct genus of dinosaurs

Yandusaurus is a genus of herbivorous basal neornithischian dinosaur from the Bathonian age of China.

<i>Agilisaurus</i> Extinct genus of dinosaurs

Agilisaurus is a genus of ornithischian dinosaur from the Middle Jurassic Period of what is now eastern Asia. It was about 3.5–4 ft long, 2 ft in height and 40 kg in weight.

<i>Huayangosaurus</i> Extinct genus of dinosaurs

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.

<i>Tuojiangosaurus</i> Extinct genus of dinosaurs

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.

<i>Omeisaurus</i> Extinct genus of dinosaurs

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.

<i>Datousaurus</i> Extinct species of reptile

Datousaurus was a dinosaur from the Middle Jurassic. It was a sauropod collected from the Lower Shaximiao Formation in Dashanpu, Zigong Sichuan province, China. It shared the local Middle Jurassic landscape with other sauropods such as Shunosaurus, Omeisaurus, Protognathosaurus, the ornithopod Xiaosaurus, the early stegosaur Huayangosaurus as well as the carnivorous Gasosaurus.

Bashunosaurus is a genus of potentially macronarian sauropod dinosaur from the Middle Jurassic Shaximiao Formation of Kaijiang, China. The type and only species is Bashunosaurus kaijiangensis.

Chinshakiangosaurus is a genus of dinosaur and probably one of the most basal sauropods known. The only species, Chinshakiangosaurus chunghoensis, is known from a fragmentary skeleton found in Lower Jurassic rocks in China. Chinshakiangosaurus is one of the few basal sauropods with preserved skull bones and therefore important for the understanding of the early evolution of this group. It shows that early sauropods may have possessed fleshy cheeks.

<i>Chungkingosaurus</i> Extinct genus of dinosaurs

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.

Daanosaurus was a genus of dinosaur. It was a sauropod which lived during the Late Jurassic. It lived in what is now China, and was similar to Bellusaurus.

<i>Hexinlusaurus</i> Extinct genus of dinosaurs

Hexinlusaurus is a genus of basal ornithischian dinosaur from the Middle Jurassic of China.

<i>Yuanmousaurus</i> Extinct genus of dinosaurs

Yuanmousaurus was a sauropod dinosaur from the Middle Jurassic period of China. It is known from incomplete remains, recovered in 2000 from the Zhanghe Formation in Yuanmou County in Yunnan Province. Yuanmousaurus was a relatively large sauropod and may have reached about 17 meters (56 ft) in length. It was a basal member of the Sauropoda, but its exact systematic position is unclear. A recent study placed Yuanmousaurus within the family Mamenchisauridae. It may be a dubious genus. The only and type species was Yuanmousaurus jiangyiensis.

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.

<span class="mw-page-title-main">Shaximiao Formation</span> Late Jurassic geological formation in China

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.

References

  1. ↑ Wang, Jun; Ye, Yong; Pei, Rui; Tian, Yamin; Feng, Chongqin; Zheng, Daran; Chang, Su-Chin (2018-09-01). "Age of Jurassic basal sauropods in Sichuan, China: A reappraisal of basal sauropod evolution". GSA Bulletin. 130 (9–10): 1493–1500. doi:10.1130/B31910.1. ISSN   0016-7606.
  2. ↑ Dong, Z., Zhou, S. & Zhang, Y. 1983. [Dinosaurs from the Jurassic of Sichuan]. Palaeontologica Sinica, New Series C 162(23): 1-136
  3. ↑ Zhang Y., Yang D. & Peng G., 1984, "[New materials of Shunosaurus from the Middle Jurassic of Dashanpu, Zigong, Sichuan]", Journal of Chengdu College of Geology2: 1–12
  4. ↑ Fu, L.; Zhang, J. (2004). "A new species of sauropod from the Middle Jurassic of Jiangyi, Yuanmou". Yunnan Geology (in Chinese). 23 (1): 73–76.
  5. ↑ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 173
  6. ↑ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 175
  7. ↑ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs , Princeton University Press p. 174
  8. ↑ Zheng , Zhong (1996). Cranial Anatomy of Shunosaurus and Camarasaurus (Dinosauria: Sauropoda) and the phylogeny of the Sauropoda. Dissertation Texas Tech University. pp. 208
  9. ↑ Dong Z., Peng G., Huang D. 1989. [The discovery of the bony tail club of sauropods]. Vertebrata PalAsiatica27: 219–224
  10. ↑ Dong Zhiming (1992). Dinosaurian Faunas of China. China Ocean Press, Beijing. ISBN   3-540-52084-8.
  11. ↑ P. Upchurch. 1995. "The evolutionary history of sauropod dinosaurs". Philosophical Transactions of the Royal Society of London B349: 365-390
  12. ↑ J. A. Wilson. 2002. "Sauropod dinosaur phylogeny: critique and cladistic analysis". Zoological Journal of the Linnean Society136: 217-276
  13. ↑ Chatterjee, S. & Zheng, Z. 2002. "Cranial anatomy of Shunosaurus, a basal sauropod dinosaur from the Middle Jurassic of China". Zoological Journal of the Linnean Society136(1): 145–169
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