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Temporal range: Early Jurassic
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Genus: Pachysuchus
Young, 1951
  • P. imperfectus Young, 1951 (type)

Pachysuchus is a dubious extinct genus of basal sauropodomorph dinosaur from the Early Jurassic of China.

Pachysuchus is known from a poorly preserved partial rostrum that was described from the Lower Lufeng Series in Yunnan by paleontologist Yang Zhongjian ("C.C. Young") in 1951.[1] The type species is Pachysuchus imperfectus. The generic name translates as "thick crocodile"; the specific name means "imperfect" in Latin. Young identified the rostrum as that of a phytosaur, a long-snouted crocodile-like crurotarsan. Phytosaurs were common in the Triassic, but none are otherwise known from the Jurassic. They are thought to have gone extinct during the Triassic-Jurassic extinction event. The rostrum from which Young described the specimen had since been lost, and his first description of the genus had been questioned.[2] The poor preservation of the specimen and its presence in Jurassic beds makes it doubtful that Pachysuchus is a phytosaur.[3] Paul M. Barrett and Xu Xing (2012) relocated the holotype of P. imperfectus, specimen IVPP V 40, and identified it as actually belonging to a taxonomically indeterminate basal sauropodomorph. According to Barrett and Xu, the holotype of Pachysuchus "does not bear any unique features or a unique character combination"; it differs from rostra of other Early Jurassic Chinese sauropodomorphs, but it cannot be ruled out that the differences are caused by its poor preservation, making it a nomen dubium.[4]


  1. ^ Young, C.C., 1951, "The Lufeng saurischian fauna in China", Palaeontologia Sinica, New Series C, 13: 1-96
  2. ^ Padian, K. (1989). "Did "thecodontians" survive the Triassic?". In Lucas, S.G. and Hunt, A.P. (eds.) (eds.). Dawn of the Age of Dinosaurs in the American Southwest. Albuquerque: New Mexico Museum of Natural History. pp. 401–414.CS1 maint: Uses editors parameter (link)
  3. ^ Sun, A.-L.; Cui, K.H. (1986). "A brief introduction to the Lower Lufeng saurischian fauna (Lower Jurassic, Lufeng, Yunnan, People's Republic of China)". In Padian, K. (ed.) (eds.). The Beginning of the Age of Dinosaurs: Faunal Change Across the Triassic-Jurassic Boundary. New York: Cambridge University Press. pp. 275–278.CS1 maint: Uses editors parameter (link)
  4. ^ Paul M. Barrett and Xu Xing (2012). "The enigmatic reptile Pachysuchus imperfectus Young, 1951 from the Lower Lufeng Formation (Lower Jurassic) of Yunnan, China" (PDF). Vertebrata PalAsiatica. 50 (2): 151–159.