Open Paleo

Yuanmousaurus

Lü et al., 2006 ywahn-moo-sore-us

Named for Yuanmou County in Yunnan, China, where the fossils were recovered, combined with Greek 'sauros' meaning 'lizard'.

174.7–165.3 million years ago Aalenian–Bathonian, Middle Jurassic
Middle Jurassic stages

Yuanmousaurus was a sauropod dinosaur from the Middle Jurassic period of China. It is known from incomplete remains, recovered in 2000 from the Zhanghe Formation in Yuanmou County in Yunnan Province. Yuanmousaurus was a relatively large sauropod and may have reached about 17 meters (56 ft) in length. It was a basal member of the Sauropoda, but its exact systematic position is unclear. A recent study placed Yuanmousaurus within the family Mamenchisauridae. It may be a dubious genus. The only and type species was Yuanmousaurus jiangyiensis.

Diagnosis

  1. Dorsal vertebral neural spines with dorsoventrally-oriented cavities demarcated by parallel anterior and posterior margins, similar to Omeisaurus and Patagosaurus
  2. Each dorsal vertebra bears 9 laminae, forming three cavities on the lateral surface of the neural arch
  3. Dorsal neural structures more complex than Omeisaurus but simpler than Euhelopus
  4. Deltopectoral crest narrow, ratio of humeral length to femoral length approximately 0.72
  5. Fourth trochanter is low and rounded

Species

Yuanmousaurus jiangyiensis Lü et al., 2006

Type species

Named for the village of Jiangyi in Yuanmou County, Yunnan Province, China, where the only known specimen was collected.

Holotype
YMV 601 , Yuanmou Museum
Material
Incomplete skeleton without skull, including anterior part of cervical vertebra, 9 dorsal vertebrae, two and a half posterior sacral vertebrae, 7 caudal vertebrae, both almost complete scapulae, one nearly complete right humerus, right ulna and radius, partial right ilium, one right complete femur, one right tibia and fibula, one astragalus, one ungual, and other bone fragments.
Horizon
Zhanghe Formation, Aalenian–Bathonian, Middle Jurassic , 174.7–165.3 million years ago
Locality
Banqing Houshanliangzi, Jiangyi, Yunnan, China

References

  1. Lü, J.; Li, S.; Wang, G.; Zhang, J.; Dong, Z. (2006). New eusauropod dinosaur from Yuanmou of Yunnan province, China. Acta Geologica Sinica (English Edition) 80(1): 1-10. doi:10.1111/j.1755-6724.2006.tb00788.x lü2006a
  2. Lü, J.; Li, T.; Zhong, S.; Ji, Q.; Li, S. (2008). A new mamenchisaurid dinosaur from the Middle Jurassic of Yuanmou, Yunnan Province, China. Acta Geologica Sinica (English Edition) 82(1): 17-26. Wiley. doi:10.1111/j.1755-6724.2008.tb00320.x

    Gives Banqing Houshanliangzi of Jiangyi as the Eomamenchisaurus type locality and reports Yuanmousaurus from the same locality.

    lü2008a
  3. Lü, J.; Li, T.; Zhong, S.; Azuma, Y.; Fujita, M.; Dong, Z.; Ji, Q. (2007). New yunnanosaurid dinosaur (Dinosauria, Prosauropoda) from the Middle Jurassic Zhanghe Formation of Yuanmou, Yunnan Province of China. Memoir of the Fukui Prefectural Dinosaur Museum 6: 1-15.

    Reports Yuanmousaurus from the same area as Yunnanosaurus youngi, whose type locality it gives as Banqing Houshanliangzi of Jiangyi.

    lü2007d
  4. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the mass estimate.

    paul2024a
  5. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

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

    jones2026b