Huayangosaurus
Name:
Huayangosaurus
(Huayang lizard - Huayang is an alternative name for Sichuan
Province).
Phonetic: Hu-ay-ang-o-sore-us.
Named By: Dong, Tang & Zhou - 1982.
Classification: Chordata, Reptilia, Dinosauria,
Ornithischia, Thyreophora, Stegosauria, Huayangosauridae.
Species: H. taibaii (type).
Diet: Herbivore.
Size: Around 4.5 meters long.
Known locations: China - Sichuan Province -
Dashanpu/Lower Shaximiao Formation.
Time period: Bathonian/Callovian of the Jurassic.
Fossil representation: Several individuals including
some almost complete.
With
fossils going back to the mid Jurassic, it comes as no surprise that
Huayangosaurus is a more primitive stegosaur
than
better known genera
from the late Jurassic. The skull of Huayangosaurus
is broader than
later forms which reveals it was not as well adapted to selective
browsing. The premaxilla also still has teeth, which would
disappear from more advanced forms. The back plates of Huayangosaurus
are tall and spike-like though a clear distinction can still be made
between them and proper spikes. The thagomizer of the tail has the
stegosaur standard of two pairs of spikes that point out to the sides.
Huayangosaurus
is the best known stegosaur from the Lower Shaximiao Formation, with
other stegosaur genera from the collective Dashanpu Formation which
include Chungkingosaurus,
Chialingosaurus,
Gigantspinosaurus
and
Tuojiangosaurus
all being recovered from the upper Shaximiao
Formation. Conditions in Dashanpu seem to be conducive to producing
small stegosaurs since out of these four, only Tuojiangosaurus
is
bigger than Huayangosaurus.
Huayangosaurus
still lived amongst similar fauna to its later relatives, with the
next dominant type of herbivores being sauropods
such as Omeisaurus
and
Shunosaurus
being common. Huayangosaurus also had
no shortage of
potential predators with candidates including Yangchuanosaurus,
Xuanhanosaurus,
Gasosaurus
and Kaijiangosaurus,
with possible
others also posing threats.
Further reading
- Note on the new Mid-Jurassic stegosaur from Sichuan Basin, China. -
Vertebrata PalAsiatica 20(1):83-87. - Z. Dong, Z. Tang & S.-w.
Zhou - 1982.
- The skull of the basal stegosaur Huayangosaurus taibaii
and a
cladistic diagnosis of Stegosauria. - Journal of Vertebrate
Paleontology 51: 318-343. - P. Sereno & Z. -M. Dong - 1992.
- Re-description of the postcranial skeleton of the Middle Jurassic
stegosaur Huayangosaurus taibaii. - Journal of
Vertebrate Paleontology,
26: 944-956. - S. C. Maidment, G. -B. Wei & D. B. Norman -
2006.
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