Huayangosaurus
Encyclopedia
Huayangosaurus is a genus
of stegosaurian dinosaur
from the Middle Jurassic
of China
. The name derives from "Huayang", an alternate name for Sichuan
(the province where it was discovered), 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 4.5 metres 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
.
Like other stegosaurians, Huayangosaurus was a quadruped
al herbivore
with a small skull
and a spiked tail
. Like its more famous relative, Stegosaurus, Huayangosaurus bore the distinctive double row of plates that characterize all the stegosaurians. These plates rose vertically along its arched back. In Huayangosaurus, the plates were more spike-like than in Stegosaurus. Like Stegosaurus, however, it bore two pairs of long spikes extending horizontally near the end of its tail.
Huayangosaurus was one of the smallest known stegosaurians, at just 4.5 meters (15 feet) in length.
, Tang, and Zhou in 1982. The type species
is H. taibaii.
, with much less surface area. Thus they would have been much less effective heat regulators, one of the postulated functions of plates.
and the Municipal Museum of Chongqing
in Sichuan
Province in China.
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 stegosaurian 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 the Middle Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
of 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...
. The name derives from "Huayang", an alternate name for 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...
(the province where it was discovered), and "saurus", meaning "lizard". It lived during the 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...
to 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....
stages, around 165 million years ago, some 20 million years before its famous relative, Stegosaurus
Stegosaurus
Stegosaurus is a genus of armored stegosaurid dinosaur. They lived during the Late Jurassic period , some 155 to 150 million years ago in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well...
appeared in North America. At only 4.5 metres 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
Shunosaurus
Shunosaurus, meaning "Shu Lizard", is a genus of sauropod dinosaur from Middle Jurassic beds in Sichuan Province in China, 170 million years ago...
, 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 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 carnivorous 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...
.
Description
Quadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
al herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
with a small skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
and a spiked tail
Thagomizer
Thagomizer is an informal name for the distinctive arrangement of four to ten spikes on the tails of stegosaurid dinosaurs. These spikes are believed to have been a defensive measure against predators.-Paleobiology:...
. Like its more famous relative, Stegosaurus, Huayangosaurus bore the distinctive double row of plates that characterize all the stegosaurians. These plates rose vertically along its arched back. In Huayangosaurus, the plates were more spike-like than in Stegosaurus. Like Stegosaurus, however, it bore two pairs of long spikes extending horizontally near the end of its tail.
Huayangosaurus was one of the smallest known stegosaurians, at just 4.5 meters (15 feet) in length.
Discovery and species
Huayangosaurus remains from twelve individual animals were recovered from the Dashanpu Quarry near Zigong in Sichuan, and named by DongDong 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...
, Tang, and Zhou in 1982. The type species
Type 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...
is H. taibaii.
Classification
As it is the most basal stegosaurian, it is placed in within its own family Huayangosauridae. It is also morphologically distinct from later (stegosaurid) forms. Its skull was broader and had premaxillary teeth in the front of its mouth. All later stegosaurians lost these teeth.Palaeobiology
Like many other stegosaurians, it had plates all down its back and spikes on its tail. Two large spikes were above its hips, and may have been used for deterring an attack from above (considering as it was a fairly short in height compared to later stegosaurians). Its plates were smaller than those of StegosaurusStegosaurus
Stegosaurus is a genus of armored stegosaurid dinosaur. They lived during the Late Jurassic period , some 155 to 150 million years ago in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well...
, with much less surface area. Thus they would have been much less effective heat regulators, one of the postulated functions of plates.
Popular culture
Mounted skeletons of Huayangosaurus are on display at the Zigong Dinosaur Museum in ZigongZigong
Zigong , ancient name Ziliujing and Gongjing, is a prefecture-level city and the third largest city in Sichuan Province, in southwest China.-Geography:...
and the Municipal Museum of Chongqing
Chongqing
Chongqing is a major city in Southwest China and one of the five national central cities of China. Administratively, it is one of the PRC's four direct-controlled municipalities , and the only such municipality in inland China.The municipality was created on 14 March 1997, succeeding the...
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.