Szechuanosaurus
Name:
Szechuanosaurus
(Szechuan lizard).
Phonetic: Zee-choo-an-o-sore-us.
Named By: Young - 1942.
Synonyms: S. yandonensis.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Theropoda, Neotheropoda.
Species: S. campi (type).
Diet: Carnivore.
Size: Unknown due to lack of skeletal remains.
Known locations: China - Dashanpu
(Shangshaximiao) Formation.
Time period: Oxfordian/Kimmeridgian of the Jurassic.
Fossil representation: Teeth.
In
modern times Szechuanosaurus is widely regarded as
a dubious genus
because it has only been described from a collection of isolated
teeth. Also, because these teeth do not really have any
specifically characteristic features, it is highly unlikely that
skeletal remains could be later attributed to these teeth (like what
happened with Troodon).
With the teeth officially described as
indeterminate, Szechuanosaurus will continue to
be called a ‘tooth
taxon’ that represents an unknown theropod, that may actually
already have been described, but we can never know for certain.
There
has however been past attempts to assign post cranial remains to the
teeth of Szechuanosaurus. A partial skeleton
first described in
1978 (Dong et al) as Szechuanosaurus "yandonensis"
was
officially assigned to the type species S. campi
in 1983. However
a 2012 study (Carrano, Benson & Sampson) has now
placed these remains within Yangchuanosaurus
shangyouensis, another
theropod from the Dashanpu Formation, but one that is a lot better
represented by fossils. Remains of a third species, S.
zigongensis, were also attributed to Yangchuanosaurus
at this time.
Because
only teeth are known for Szechuanosaurus it is
impossible to infer
anything beyond that it has a theropod and a meat eater. Hailing from
the Dashanpu Formation however it did live alongside many other
theropods, assuming that the teeth do not actually belong to any of
these genera of course. As of 2012 and aside from
Yangchuanosaurus these other genera also include Sinraptor,
Chuandongocoelurus,
Kaijiangosaurus,
Gasosaurus,
Leshansaurus
and Xuanhanosaurus.
Possible prey dinosaurs of all of these theropods
could include ornithopods like Agilisaurus,
stegosaurs like
Chialingosaurus
and Huayangosaurus
as well as sauropods such as
Datousaurus
and Mamenchisaurus.
Further reading
- The phylogeny of Tetanurae (Dinosauria: Theropoda), M.
T. Carrano, R. B. J. Benson & S. D. Sampson
- 2012.
- [The dinosaurian remains of Sichuan Basin, China].
Palaeontologica Sinica, Z-M Dong, S. Zhou & Y.
Zhang - 1983.
- A new species of Szechuanosaurus from the Middle
Jurassic of
Dashanpu, Zigong, Sichuan. - Vertebrata PalAsiatica 31(4): 308-314. -
Y. Gao - 1993.
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