Shunosaurus
Encyclopedia
Shunosaurus, meaning "Shu Lizard", is a genus
of sauropod dinosaur
from Middle Jurassic
(Bathonian
–Callovian
) beds in Sichuan
Province in China
, 170 million years ago. The name derives from "Shu", an ancient name for Sichuan.
, 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.
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, 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 Beijing Museum of Natural History
.
A 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
.
estimated the length at 9.5 metres (31.2 ft), the weight at 3 metric tons (3.3 ST). Shunosaurus was very short-necked for a sauropod, being only "surpassed" in this respect by Brachytrachelopan
. The skulls found are mostly compressed or disarticulated and the interpretation of the head form has varied from broad, short and deep to extremely narrow and pointed. 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. In 1989 it was disclosed that the tail ended in a club
, equipped on its top with two successive spikes formed by 5 centimetres (2 in)-long cone-shaped osteoderm
s probably used to fend off enemies.
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. However, an analysis by Jeffrey Wilson in 2002 indicated it had a very basal position within the Eusauropoda. Shunosaurus is perhaps related to Rhoetosaurus
from Queensland
in Australia
.
Shunosaurus accounts for 90% of the fossils found in the Dashanpu fauna, showing it was a dominant member of its habitat
. 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
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of sauropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
from Middle Jurassic
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....
(Bathonian
Bathonian
In the geologic timescale the Bathonian is an age or stage of the Middle Jurassic. It lasted from approximately 167.7 Ma to around 164.7 Ma...
–Callovian
Callovian
In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....
) beds in Sichuan
Sichuan
' , known formerly in the West by its postal map spellings of Szechwan or Szechuan is a province in Southwest China with its capital in Chengdu...
Province in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, 170 million years ago. The name derives from "Shu", an ancient name for Sichuan.
Discovery and species
The first fossil of Shunosaurus was discovered in 1977 by a group of students, practising paleontological excavation at a road bank. The type speciesType species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, Shunosaurus lii, was described and named by Dong Zhiming
Dong Zhiming
Dong Zhiming , from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, is one of China's leading paleontologists. He began working at the IVPP in 1962, learning from Yang Zhongjian who was director at the time...
, 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.
The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, IVPP V.9065, was collected from the Lower Xiashaximiao Formation near Dashanpu, Zigong
Zigong
Zigong , ancient name Ziliujing and Gongjing, is a prefecture-level city and the third largest city in Sichuan Province, in southwest China.-Geography:...
. It consists of a partial skeleton. Later about twenty more major specimens were discovered, including several complete or near-complete skeletons, skulls and juveniles, 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
Zigong
Zigong , ancient name Ziliujing and Gongjing, is a prefecture-level city and the third largest city in Sichuan Province, in southwest China.-Geography:...
, Sichuan
Sichuan
' , known formerly in the West by its postal map spellings of Szechwan or Szechuan is a province in Southwest China with its capital in Chengdu...
Province, and the Beijing Museum of Natural History
Beijing Museum of Natural History
The Beijing Museum of Natural History is located at 126, Tian Qiao Nan Street, Chong Wen District, Beijing, 100050, and is the most popular natural history museum in China. It was originally founded in 1951 as the National Central Museum of Natural History, and its name changed to the Beijing...
.
Nomen nudum
The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
.
Description
Shunosaurus was first estimated to be 11 metres (36.1 ft) long; later and more complete finds indicated a somewhat smaller size. In 2010 Gregory S. PaulGregory S. Paul
Gregory Scott Paul is a freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dinosaurs and his detailed illustrations, both live and skeletal...
estimated the length at 9.5 metres (31.2 ft), the weight at 3 metric tons (3.3 ST). Shunosaurus was very short-necked for a sauropod, being only "surpassed" in this respect by Brachytrachelopan
Brachytrachelopan
Brachytrachelopan is an unusual short-necked sauropod dinosaur from the latest Jurassic Period of Argentina. The holotype and only known specimen was collected from an erosional exposure of fluvial sandstone within the Cañadón Cálcero Formation on a hill approximately 25 km north-northeast...
. The skulls found are mostly compressed or disarticulated and the interpretation of the head form has varied from broad, short and deep to extremely narrow and pointed. 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. In 1989 it was disclosed that the tail ended in a club
Club (zoology)
In zoology, a club is a bony mass at the end of the tail of some dinosaurs and of some mammals, most notably the ankylosaurids and the glyptodonts...
, equipped on its top with two successive spikes formed by 5 centimetres (2 in)-long cone-shaped osteoderm
Osteoderm
Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...
s probably used to fend off enemies.
Classification
Shunosaurus was originally classified as a member of the Cetiosaurinae; in 1992 Dong assigned it to Shunosaurinae within the Cetiosauridae.Cladistic analyses have rendered conflicting results. In 1995 Paul Upchurch published a study in which Shunosaurus belonged to the Euhelopodidae
Euhelopodidae
Euhelopodidae is a family of sauropod dinosaurs which includes the genus Euhelopus. The family name was first proposed by American paleontologist Alfred Sherwood Romer in 1956. The four genera Chiayusaurus, Omeisaurus, Tienshanosaurus, and Euhelopus were the original proposed euhelopodines...
together with other Jurassic Chinese sauropods. However, an analysis by Jeffrey Wilson in 2002 indicated it had a very basal position within the Eusauropoda. Shunosaurus is perhaps related to Rhoetosaurus
Rhoetosaurus
Rhoetosaurus , named after Rhoetus, a titan in Greek Mythology, is a genus of sauropod dinosaur from the Jurassic of what is now eastern Australia. Rhoetosaurus is estimated to have been about 12–15 metres long...
from Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Paleobiology
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.Shunosaurus accounts for 90% of the fossils found in the Dashanpu fauna, showing it was a dominant member of its habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
. It shared the local Middle Jurassic landscape with other sauropods, Datousaurus
Datousaurus
Datousaurus, meaning either "Chieftain lizard" or "Big-head Lizard" was a dinosaur from the Middle Jurassic. It was a sauropod collected from the Lower Shaximiao Formation in Dashanpu, Zigong Sichuan province, China...
, Omeisaurus
Omeisaurus
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.Like other sauropods, Omeisaurus was herbivorous and large...
and Protognathosaurus
Protognathosaurus
Protognathosaurus is a genus of dinosaur from the Middle Jurassic. It was a sauropod found in what is present-day China. The type species, P. oxyodon, was originally described by Zhang , and was renamed by George Olshevsky in 1991...
, the possible ornithopod
Ornithopod
Ornithopods or members of the clade Ornithopoda are a group of ornithischian dinosaurs that started out as small, bipedal running grazers, and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world, and dominated the North American...
Xiaosaurus
Xiaosaurus
Xiaosaurus , is a genus of small herbivorous dinosaur from the middle Jurassic, approximately 169 to 163 mya. Xiaosaurus lived in what is now the Sichuan Basin of China....
, and the early stegosaur
Stegosauria
Known colloquially as stegosaurs, the Stegosauria are a group of herbivorous dinosaurs of the Jurassic and Early Cretaceous Periods, being found mostly in the Northern Hemisphere, predominantly in what is now North America and China....
Huayangosaurus
Huayangosaurus
Huayangosaurus is a genus of stegosaurian dinosaur from the Middle Jurassic of China. The name derives from "Huayang", an alternate name for Sichuan , and "saurus", meaning "lizard"...
, as well as the carnivorous theropod Gasosaurus
Gasosaurus
Gasosaurus was a tetanuran dinosaur discovered in Dashanpu, China. The scientific name, meaning "Gas Lizard", honours the gasoline company that found the Dashanpu fossil quarry in Sichuan Province, now named as the Lower Shaximiao Formation. It had strong legs but short arms, and like most...
.