Open Paleo

Sanxiasaurus

Li et al., 2021 san-zee-uh-SOR-us

Named for Sanxia (Three Gorges) of the Yangtze River in China, near the type locality, combined with Greek 'sauros' meaning 'lizard'; meaning 'Sanxia lizard.'

184.2–170.9 million years ago Toarcian–Aalenian, Early Jurassic–Middle Jurassic
Early Jurassic and Middle Jurassic stages

Sanxiasaurus is a genus of neornithischian dinosaur from the Middle Jurassic Xintiangou Formation in the Chongqing Municipality of China. The type and only species is S. modaoxiensis. The holotype is a partial postcranial skeleton consisting of 55 bones including two cervical vertebrae, 11 dorsal vertebrae, 4 sacral vertebrae, 18 caudal vertebrae, both humeri, radii, and ulnas, partial right ilium, partial right ischium, both femora and tibiae, left fibula, 3 metatarsi and 4 phalanges. In a phylogenetic analysis, it was found to be a basal neornithischian, more derived than Lesothosaurus and less derived than Hexinlusaurus.

Diagnosis

  1. At least four sacrals (vs. two in basal ornithischians)
  2. Humerus strongly bowed laterally along its length
  3. Obturator process located at mid-length of ischial shaft
  4. Lesser trochanter of femur broadened, wing-shaped, subequal in anteroposterior width to greater trochanter
  5. Distal tibia with elongate posterolateral process

Species

Sanxiasaurus modaoxiensis Li et al., 2021

Type species

Named for the Modaoxi, a tributary of the Yangtze River near the discovery locality in Yunyang County, Chongqing.

Holotype
CLGPR V00003 , Chongqing Laboratory of Geoheritage Protection and Research
Material
Partial skeleton
Horizon
upper Xintiangou Formation, Toarcian–Aalenian, Early Jurassic–Middle Jurassic , 184.2–170.9 million years ago
Locality
Laojun Village, Pu'an Township, Yunyang County, Chongqing, China

References

  1. Li, N.; Dai, H.; Tan, C.; Hu, X.; Wei, Z.; Lin, Y.; Wei, G.; Li, D.; Meng, L.; Hao, B.; You, H.; Peng, G. (2021). A neornithischian dinosaur from the Middle Jurassic Xintiangou Formation of Yunyang, Chongqing, China: the earliest record in Asia. Historical Biology 33(7): 1089-1102. Informa UK Limited. doi:10.1080/08912963.2019.1679129 li2021a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the body length estimate.

    jones2026a