Omeisaurus

Last updated

Omeisaurus
Temporal range: 168.2–161.5  Ma
Zigong Dinosaur Museum Omeisaurus tianfuensis (cropped).jpg
O. tianfuensis on display at the Zigong Museum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade:† Sauropodomorpha
Clade:† Sauropoda
Family:† Mamenchisauridae
Genus:† Omeisaurus
Young, 1939
Type species
†Omeisaurus junghsiensis
Young, 1939 [1]
Species
  • †O. junghsiensisYoung, 1939 [1]
  • †O. changshouensisYoung, 1958 [2]
  • †O. fuxiensis Dong, Zhou & Zhang, 1983
  • †O. tianfuensisHe et al., 1984
  • †O. luoquanensisHe, Li & Cai, 1988
  • †O. maoianusTang et al., 2001
  • †O. jiaoiJiang et al., 2011
  • †O. puxianiTan et al., 2021 [3]

Omeisaurus (meaning "Omei lizard") is a genus of sauropod dinosaur from the Middle Jurassic Period (Bathonian-Callovian stage) of what is now China. Its name comes from Mount Emei, where it was discovered in the lower Shaximiao Formation of Sichuan Province. [1]

Contents

Like most sauropods, Omeisaurus was herbivorous and large. The largest species, O. tianfuensis, measured 18–20.2 metres (59–66 ft) long, and weighed 8.5–9.8 metric tons (9.4–10.8 short tons). [4] [5] Other species were much smaller, as the type species O. junghsiensis reached a size of 14 metres (46 ft) in length and 4 metric tons (4.4 short tons) in body mass, and O. maoianus reached a size of 15 metres (49 ft) and 5 metric tons (5.5 short tons). [4]

Discovery and species

Initial discovery and O. changshouensis

The initial discovery of Omeisaurus was in 1936 when Charles Lewis Camp and Yang Zhongjian collected a partial skeleton from strata of the Shaximiao Formation in Sichuan, China. [6] [7] The material was taken to and prepared in what is now the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. [7] The skeleton was named Omeisaurus junghsiensis in 1939 by Yang Zhongjian, the skeleton consisting of a partial postcranial skeleton that included four cervical (neck) vertebrae. [6] It was named after the sacred mountain Omeishan, which is near where O. junghsiensis was found, and the species name after the locality. [1] The skeleton of O. junghsiensis was lost during WWII. [7] In 1955, Xuanmin Li and colleagues collected several Sauropod remains from the same strata as O. junghsiensis in Changshou during construction of a reservoir. [6] The IVPP sent Youling Su to conduct the excavation in Changshou, the crew finding eleven vertebrae and several appendicular elements (IVPP V930). The specimen was described later in 1958, also by Yang Zhongjian, [8] [7] as a new species, O. changshouensis. [7]

Discoveries at Wujiaba

During the construction of the Wujiaba Dam in Zigong during the mid-to-late 1970s, crews discovered many large Sauropod remains from strata of the Upper Shaximiao Formation. [7] The amount of material was vast and was collected by the Chongqing Museum of Natural History over five years, and was prepped and briefly described. [7] The material consisted of many partial skulls and skeletons, consisting of between thirteen and sixteen individuals and 2 composite skeletons were later mounted in Chongqing and Zigong. [7] Wujiaba also saw the collection of a fragmentary partial skull of an additional species of Omeisaurus, Omeisaurus fuxiensis, that was described by Zhiming Dong and colleagues in 1983. [7]

Dashanpu Quarry finds

O. tianfuensis Omeisaurus tianfuensis34.jpg
O. tianfuensis

The next and most bountiful Omeisaurus discovery came in the 1980s when many dinosaur remains were found at Dashanpu in Zigong, these remains including a nearly complete skeleton, several skulls, and additional postcrania from several individuals. [9] The best of these skeletons, a nearly complete and semi articulated postcranial skeleton (ZDM T5701), was selected as the holotype and described by He et al in 1984. [10] [9] A nearly complete skull and partial postcranial skeleton (ZDM T5702) was selected as the paratype, and is one of the few known Omeisaurus specimens with a well preserved skull. The several specimens were described in much detail later in 1988, with a skeleton mounted at the Zigong Dinosaur Museum sometime later. [9] Interestingly, O. tianfuensis was discovered to have a tail club on the end of its caudal vertebrae based on a specimen from Dashanpu. [11] [12] A second new species was named in 1988, O. luoquanensis, in the osteology of O. tianfuensis off of a partial postcranial skeleton. [9]

Recent discoveries

Several Omeisaurus species have been named since the 1980s, with the most complete of them coming in 2001 with Omeisaurus maoianus from the Shaximiao Formation in Jingyan. [13] O. maoianus was collected by Jin Xingshen and Zhang Guojin during the 1990s and the remains consisted of a skull, partial vertebral column, and several additional postcranial elements (ZNM N8510). [13] O. maoianus was mounted at the Zhejiang Natural History Museum with its holotype skull on display. [13] O. maoianus' generic assessment has been questioned, with several phylogenetic analyses finding it more closely related to Mamenchisaurus and Xinjiangtitan. [14] [15] [16] 10 years later in 2011, Omeisaurus jiaoi was named based on a well preserved and partially articulated postcranial skeleton, also from Zigong and is deposited at the Zigong Dinosaur Museum (ZDM 5050). [17] The most recently named Omeisaurus species, O. puxiani, was discovered in Yunyang and is one of the best preserved Omeisaurus species, with fossils from most of the vertebral column and girdles recovered. [18] The specimen is deposited under CLGRP V00005 at the Chongqing Laboratory of Geoheritage Protection and Research. [18]

Classification

Size comparison of O. tianfuensis "Omeisaurus" tianfuensis Scale.svg
Size comparison of O. tianfuensis
O. tianfuensis mount on display in Hong Kong Taikoodino.JPG
O. tianfuensis mount on display in Hong Kong

It was once classified as a member of the family Cetiosauridae, which had long been a wastebasket taxon. The species O. fuxiensis is sometimes confused with Zigongosaurus , but the two are based on different material despite having the same species name.

Omeisaurus was formerly assigned to Euhelopodidae. [1] However, it and other Jurassic sauropods from Asia formerly assigned to Euhelopodidae are now placed in the separate family Mamenchisauridae, which is more basal in Sauropoda. In 2021, John D'Angelo determined that all Omeisaurus species, besides O. maoianus, were valid and likely members of the same genus, with O. junghsiensis as the most basal species. [15]

The cladogram from Tan et al., 2020 below shows a possible phylogenetic position:

Sauropoda

Paleoecology

Omeisaurus lived in dense forests. Different species of Omeisaurus sometimes shared habitats with each other (O. junghsiensis and O. tianfuensis, for example). In addition to other species of Omeisaurus, Shunosaurus and Datousaurus are also known from the Xiashaximiao Formation, while Mamenchisaurus is present in the Shangshaximiao Formation. Yangchuanosaurus is a large theropod from the Shangshaximiao, and it probably preyed on sauropods. The smaller Xuanhanosaurus was also present. In the Xiashaximiao, another theropod, Gasosaurus , was also present, as was the herbivorous stegosaur Huayangosaurus . The latter probably did not compete with sauropods for food. [19]

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 Late Jurassic periods, and was similar in size and appearance to its North American and European relative, Allosaurus. Yangchuanosaurus hails from the Upper Shaximiao 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.

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

Chialingosaurus is a genus of herbivorous stegosaurian dinosaur similar to Kentrosaurus from the Upper Shaximiao Formation, Late Jurassic beds in Sichuan Province in China. Its age makes it one of the oldest species of stegosaurs, living about 160 million years ago. Since it was an herbivore, scientists think that Chialingosaurus probably ate ferns and cycads, which were plentiful during the period when Chialingosaurus was alive.

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

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.

<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.

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>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.

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

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.

<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.

Dong Zhiming is a Chinese vertebrate paleontologist formerly employed at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing. He began working at the IVPP in 1962, studying under Yang Zhongjian, who was director at the time. He has described fossil remains of many dinosaurs. He investigated and described the Shaximiao Formation; an important contribution to science since they are composed of Middle Jurassic beds which do not commonly yield fossils.

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.

<span class="mw-page-title-main">Zigong Dinosaur Museum</span> Natural History Museum in Zigong, Sichuan

The Zigong Dinosaur Museum is located near the city of Zigong, Sichuan, China, in the township of Dashanpu.

Qijianglong is a genus of herbivorous mamenchisaurid sauropod dinosaur from the Early Cretaceous of China.

<i>Bashanosaurus</i> Extinct genus of stegosaurian dinosaurs

Bashanosaurus is an extinct genus of stegosaurian dinosaur from the Middle Jurassic Shaximiao Formation of Yunyang County, China. The genus contains a single species, Bashanosaurus primitivus, known from incomplete skeletons belonging to three individuals. It is one of the basalmost stegosaurs, as well as one of the oldest known stegosaurs, along with Adratiklit, Isaberrysaura, and Thyreosaurus.

<i>Yuzhoulong</i> Genus of macronarian sauropod dinosaurs

Yuzhoulong is a genus of macronarian sauropod dinosaur from the Middle Jurassic Shaximiao Formation of Chongqing, China. The type and only species is Yuzhoulong qurenensis.

References

  1. 1 2 3 4 5 Young, C.C. (1939). "On a New Sauropoda, with Notes on Other Fragmentary Reptiles from Szechuan". Bulletin of the Geological Society of China. 19 (3): 279–315. doi:10.1111/j.1755-6724.1939.mp19003005.x.
  2. ↑ Young, C.C. (1958). "New sauropods from China" (PDF). Vertebrata PalAsiatica. 2 (1): 1–29.
  3. ↑ Chao Tan; Ming Xiao; Hui Dai; Xu-Feng Hu; Ning Li; Qing-Yu Ma; Zhao-Ying Wei; Hai-Dong Yu; Can Xiong; Guang-Zhao Peng; Shan Jiang; Xin-Xin Ren; Hai-Lu You (2020). "A new species of Omeisaurus (Dinosauria: Sauropoda) from the Middle Jurassic of Yunyang, Chongqing, China fauna". Historical Biology: An International Journal of Paleobiology. in press. doi:10.1080/08912963.2020.1743286. S2CID   216282369.
  4. 1 2 Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs. Princeton University Press. p. 202. ISBN   978-1-78684-190-2. OCLC   985402380.
  5. ↑ Mazzetta, G.V.; et al. (2004). "Giants and Bizarres: Body Size of Some Southern South American Cretaceous Dinosaurs". Historical Biology. 16 (2–4): 1–13. CiteSeerX   10.1.1.694.1650 . doi:10.1080/08912960410001715132. S2CID   56028251.
  6. 1 2 3 Young, C. C. (1939). On a new Sauropoda, with notes on other fragmentary reptiles from Szechuan. Bulletin of the Geological Society of China, 19(3), 279-315.
  7. 1 2 3 4 5 6 7 8 9 Dong, Z. (1983). The dinosaurian remains from Sichuan basin, China. Palaeontologia Sinica, new series C, 23, 1-145.
  8. ↑ Young C C, (1958). New sauropods from China. Vert PalAsiat, 2: 1–28
  9. 1 2 3 4 Li, K., & Cai, K. (1988). The Middle Jurassic dinosaur fauna from Dashanpu, Zigong, Sichuan: Omeisaurus tianfuensis. Sauropod dinosaurs (2). Sichuan Publishing House of Science and Technology.
  10. ↑ X. He, K. Li, K. Cai and Y. Gao. (1984). "Omeisaurus tianfuensis—a new species of Omeisaurus from Dashanpu, Zigong, Sichuan". Journal of Chengdu College of Geology 1984 (suppl. 2): 13-32
  11. ↑ Lida, Xing; Yong, Y. E.; Chunkang, S. H. U.; Guangzhao, Peng; Hailu, Y. O. U. (2009). "Structure, Orientation and Finite Element Analysis of the Tail Club of Mamenchisaurus hochuanensis". Acta Geologica Sinica - English Edition. 83 (6): 1031–1040. doi:10.1111/j.1755-6724.2009.00134.x. ISSN   1755-6724. S2CID   129309522.
  12. ↑ Dong Zhiming, Peng Guangzhao and Huang Daxi. 1988. "The Discovery of the bony tail club of sauropods". Vertebrata PalAsiatica27 (3): 219-224
  13. 1 2 3 Tang F, Jin X S, Kang X M et al., 2001. Omeisaurus maoianus: a Complete Sauropoda From Jingyan, Sichuan. Beijing: China Ocean Press. 1–128
  14. ↑ Xing LD, Miyashita T, Zhang JP, Li DQ, Ye Y, Sekiya T, Wang FP, Currie PJ. 2015b. A new sauropod dinosaur from the Late Jurassic of China and the diversity, distribution, and relationships of mamenchisaurids. Journal of Vertebrate Paleontology. 35 (1):e889701.
  15. 1 2 D' Angelo, John (2021). "A Maze of Omeisaurus: Observations on the Taxonomic Status of Omeisaurus junghsiensis". Society of Vertebrate Paleontology Meeting. 2021: 94.
  16. ↑ Xin-Xin Ren; Jian-Dong Huang; Hai-Lu You (2018). "The second mamenchisaurid dinosaur from the Middle Jurassic of Eastern China". Historical Biology: An International Journal of Paleobiology.49 (2): 185-194. doi:10.1080/08912963.2018.1515935.
  17. ↑ 江山, 李飞, 彭光照, & 叶勇. (2011). A new species of Omeisaurus from the Middle Jurassic of Zigong, Sichuan. 古脊椎动物学报, 49(2), 185-194.
  18. 1 2 Tan, C., Xiao, M., Dai, H., Hu, X. F., Li, N., Ma, Q. Y., ... & You, H. L. (2021). A new species of Omeisaurus (Dinosauria: sauropoda) from the Middle Jurassic of Yunyang, Chongqing, China. Historical Biology, 33(9), 1817-1829.
  19. ↑ Paul, G.S. (2010). "Sauropodomorphs". The Princeton Field Guide to Dinosaurs. Princeton: Princeton University Press. p. 244. ISBN   9780691167664.
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