- Huayangosaurus
Taxobox
name = "Huayangosaurus"
fossil_range =Middle Jurassic
image_width = 200px
image_caption = "Huayangosaurus tianfuensis" displayed in Hong Kong.
regnum =Animal ia
phylum = Chordata
classis =Sauropsid a
superordo =Dinosaur ia
ordo =Ornithischia
subordo =Thyreophora
infraordo =Stegosauria
familia = Huayangosauridae
binomial = "Huayangosaurus taibaii"
binomial_authority = Dong, Tang, and Zhou, 1982"Huayangosaurus" is a
genus ofstegosaur iandinosaur from the MiddleJurassic ofChina . The name derives from "Huayang", an alternate name forSichuan (the province where it was discovered), and "saurus", meaning "lizard". It lived during theBathonian toCallovian 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 thesauropod s "Shunosaurus ", "Datousaurus ", "Omeisaurus " and "Protognathosaurus ", theornithopod "Xiaosaurus " and the carnivorous "Gasosaurus ".Description
Like other stegosaurians, "Huayangosaurus" was a
quadruped alherbivore with a smallskull 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 in length.
Discovery and species
"Huayangosaurus" remains from twelve individual animals were recovered from the Dashanpu Quarry near Zigong in Sichuan, and named by Dong, Tang, and Zhou in 1982. The
type species is "H. taibaii".Dong, Z., Tang, Z. and Zhou, S.W. (1982). ["Note on the new Mid-Jurassic stegosaur from Sichuan Basin, China"] (in Chinese). "Vertebrata PalAsiatica" 20 (1) :83-87]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. [Sereno, P & Z-M Dong (1992). The skull of the basal stegosaur "Huayangosaurus taibaii" and a cladistic diagnosis of Stegosauria. "Journal of Vertebrate Paleontology" 51: 318-343]
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 "
Stegosaurus ", 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
Zigong and the Municipal Museum ofChongqing inSichuan Province in China.References
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External links
* [http://www.users.qwest.net/~jstweet1/stegosauria.htm Stegosauria]
* [http://www.amonline.net.au/chinese_dinosaurs/factsheets/01.htm "Huayangosaurus" Factsheet - Australian Museum]
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