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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