Dianchungosaurus

Dianchungosaurus (meaning "Central Yunnan lizard") is an extinct genus of mesoeucrocodylian crocodylomorph from the Early Jurassic of China. It was previously considered a dinosaur, but it was recently reclassified as a mesoeucrocodylian by Paul Barrett and Xing Xu (2005).[1] It is probably the same animal as the informally named "Tianchungosaurus".[2] The type species is D. lufengensis and it was described in 1982.[2] A second species, D. elegans, was named in 1986,[3] but it has since become a synonym of the type species.[1]

Dianchungosaurus
Temporal range: Early Jurassic,
195.5–189.6 Ma
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Mesoeucrocodylia
Genus: †Dianchungosaurus
Yang, 1982
Binomial name
†Dianchungosaurus lufengensis
Yang, 1982
Synonyms
  • Dianchungosaurus elegans Zhao, 1986
  • Tianchungosaurus Young, 1982

Material

Two specimens were originally referred to this taxon:[2]

  • IVPP V4735a (holotype): an isolated premaxilla.
  • IVPP V4735b (paratype): cojoined partial left and right dentaries with teeth and left splenial

Both remains come from the Lower Lufeng Formation, in the Yunnan Province in China. The age of the material is thus Sinemurian (Early Jurassic).[1]

Systematics

Originally classified by Yang in 1982 in Heterodontosauridae, Dianchungosaurus lufengensis' affinities were doubted by some, who regarded it as a nomen dubium, but it was until recently usually considered a valid heterodontosaurid. In 2005, a paper by Barrett and Xu focused on this problematic taxon and found its specimens to form an hypodigm, a chimera of different animals. The holotype, IVPP V4735a, was reclassified as a mesoeucrocodylian, while the paratype, IVPP V4735b, was found to be an indeterminate prosauropod.[1]

To maintain the stability in the literature, the holotype retains the name D. lufengensis, while the paratype awaits a formal description.[1]

References
  1. Barrett, P.M.; Xu X. (2005). "Reassessment of Dianchungosaurus lufengensis Yang, 1982, an enigmatic reptile from the Lower Lufeng Formation (Lower Jurassic) of Yunnan Province, People's Republic of China". Journal of Paleontology. 79 (5): 981–986. doi:10.1666/0022-3360(2005)079[0981:ARODLY]2.0.CO;2.
  2. C.-C. Young. 1982. [On a new genus of dinosaur from Lufeng, Yunnan]. Selected Works of Yang Zhungjian. Science Press, Beijing 38-42
  3. Zhao, (1986). The Cretaceous biota of China: Reptilia. in Hao, Su, Yu, Li, Li, Wang, Qi, Guan, Hu, Liu, Yang, Ye, Shou and Zang (eds.). The Cretaceous System of China. Stratigraphy of China. 12, 67-73, plates XI, XII.
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