Open Paleo

Yangchuanosaurus

Dong et al., 1978 YAHNG-CHWAHN-o-SAWR-us

Named for Yongchuan (historically romanized as Yangchuan), the district in Sichuan Province, China, where the fossils were found, combined with Greek 'sauros' meaning 'lizard'.

170.9–154.8 million years ago Bajocian–Oxfordian, Middle Jurassic–Late Jurassic
Middle Jurassic and Late Jurassic stages

Yangchuanosaurus is an extinct genus of metriacanthosaurid theropod dinosaur that lived in China from the Middle Jurassic to Late Jurassic periods (Bathonian to Tithonian stages), and was similar (although slightly larger) in size and appearance to its North American and European relative, Allosaurus. Yangchuanosaurus hails from the Upper Shaximiao Formation and was the largest predator in a landscape that included the sauropods Mamenchisaurus and Omeisaurus and the stegosaurs Chialingosaurus, Tuojiangosaurus and Chungkingosaurus. This theropod was named after the area in which was discovered, Yongchuan, in China.

Diagnosis

  1. Skull with two pairs of antorbital fenestrae: first pair very large and triangular (inverted), second pair small and triangular
  2. Maxillary depression located behind the nasal naris; no gap between parietal, parietal process, and frontal bones
  3. Angular bone slopes slightly posteriorly, elongating the mandibular lobe; large mandibular foramen in posterior mandible
  4. Dental formula Pm4 M14-15 / D14-15; teeth laterally flattened, curved posteriorly, with serrated ridges (12 denticles per 5 mm)
  5. Pubis fused to distal end of ischium; pubic foot poorly developed; ascending process of astragalus poorly formed

Species

Yangchuanosaurus shangyouensis Dong et al., 1978

Type species

Named for the Shangyou Reservoir, near whose construction site the holotype was discovered in 1977.

Holotype
CV00215 , Chongqing Museum of Natural History
Material
Nearly complete skeleton (lacking forelimbs and some posterior caudal vertebrae), including a perfectly preserved skull.
Horizon
upper Shaximiao Formation, Bajocian–Oxfordian, Middle Jurassic–Late Jurassic , 170.9–154.8 million years ago
Locality
Shangyou Reservoir, Chongqing, China

References

  1. Dong, Z.; Zhang, Y.; Li, X.; Zhou, S. (1978). [A new carnosaur from Yongchuan County, Sichuan Province]. Ke Xue Tong Bao [Science Newsletter] 23(5): 302-304. dong1978a
  2. Dong, Z.; Zhou, S.; Zhang, H. (1983). [Dinosaurs from the Jurassic of Sichuan]. Palaeontologica Sinica, New Series C, Whole Number 162(23): 1-136.

    Describes the holotype skeleton in full, and gives CV00216 to the separate Yangchuanosaurus magnus, from another site.

    dong1983a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026c