|Specimen of "Dachongosaurus yunnanensis" (after Zhao, 1985).|
"Dachongosaurus yunnanensis" Zhao, 1985
"Dachungosaurus yunnanensis" Zhao, 1985
Etymology- Dachong refers to the red color of the beds it was found in, while the species name refers to the province it was discovered in.
Sinemurian, Early Jurassic
Shawan Member of the Lufeng Formation, Dafongtian, Yunnan, China
Material- (~9.7 m) partial skeleton including at least nine dorsal vertebrae (~118 mm), seventeen dorsal ribs, femur (~955 mm)
Comments- "Dachongosaurus" is used in the text, while "Dachungosaurus" is used in the plate caption. Which will be used (if either) if it is eventually officially named is unknown.
A photo of the skeleton in situ is in Zhao (1985). Li et al. (1998) include Dachongosaurus yunnanensis in a faunal list. The length is estimated based on comparison with Jingshanosaurus, using the femoral length estimated from the photo.
Relationships- Stated by Zhao (1985) to be a basal sauropod with some derived features. Lambert (1990) listed it as a cetiosaurid, which Olshevsky (1991) also referred it to provisionally. Glut (1997) merely listed it as Sauropodomorpha incertae sedis. While few details are available from the photo, the femur appears to be strongly sigmoidal unlike the condition in sauropods. While the size is large for a non-sauropod, it is approached by some taxa such as Jingshanosaurus (femur 880 mm). It may in fact be a Jingshanosaurus specimen, though the material itself has not yet been described (contra the possibility alluded to on Wikipedia), as the Jingshanosaurus holotype is positioned differently and Xixiposaurus is much smaller. For now I recommend placing it as Plateosauria incertae sedis, as the large size is at least unknown in more basal sauropodomorphs.
Reference- Li, Zhang and Cai, 1998. The Characteristics of the Composition of the Trace Elements in Jurassic Dinosaur Bones and Red Beds in Sichuan Basin. Geological Publishing House, Beijing. 155 pp.