Open Paleo

Hudiesaurus

Dong, 1997 HOO-dyeh-SAWR-us

Butterfly lizard; from Chinese hudie (butterfly) and Greek sauros (lizard)

154.8–143.1 million years ago Kimmeridgian–Tithonian, Late Jurassic
Late Jurassic stages

Hudiesaurus is an extinct genus of mamenchisaurid sauropod dinosaur that lived in present-day China during the Late Jurassic period. It was described by Chinese paleontologist Dong Zhiming in 1997. The genus contains a single species, Hudiesaurus sinojapanorum, named based on a single vertebra. However, Dong also assigned teeth and limb bones from a nearby locality to H. sinojapanorum. These fossils were unearthed by the Sino-Japanese Silk Road Expedition near Qiketai in Shanshan, Xinjiang province in rock layers coming from the Kalaza Formation. This formation dates to between the Late Kimmeridgian and Tithonian stages of the Late Jurassic, 154 to 143 million years ago. Dong believed that the vertebra was a dorsal (trunk) vertebra, but later analysis suggested that it is one of the last cervical (neck) vertebrae. In 2021, the limb bones were assigned to a distinct genus of sauropod, Rhomaleopakhus, and the teeth were classified as an indeterminate eusauropod.

Diagnosis

  1. Small projection on the neurocentral junction above the lateral pneumatic opening.
  2. Anterior centrodiapophyseal lamina (ACDL) splitting into upper and lower branches — the upper reaching the anterodorsal margin of the diapophysis, the lower the posteroventral margin where it meets the anterior end of the PCDL (this region is heavily plaster-restored, so treat with caution).
  3. Approximately transverse row of five to six small coels on the dorsal surface of the prezygapophyseal process, immediately posterior to the articular facet.
  4. Spinoprezygapophyseal laminae (SPRLs) bifurcating near the base of the metapophysis — one branch ascending the anterior surface and fading before the summit, the other forming a thin sheet along the anterolateral margin to the summit.
  5. Spinopostzygapophyseal lamina (SPOL) bifurcating into two distinct ridges immediately above the postzygapophysis.

Species

Hudiesaurus sinojapanorum Dong, 1997

Type species

Named for the members of the Sino-Japanese Silk Road Dinosaur Expedition, combining 'sino' for China and 'japonorum' for Japan, honoring the joint Chinese-Japanese team that discovered the fossils.

Holotype
IVPP V11120 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
A nearly complete vertebra from the cervicodorsal region, most probably the last cervical (Dong originally identified it as an anterior dorsal); parts of the transverse processes are restored with plaster.
Horizon
lower Kalazha Formation, Kimmeridgian–Tithonian, Late Jurassic , 154.8–143.1 million years ago
Locality
Qiketai, Xinjiang, China

References

  1. Dong, Z. (1997). A gigantic sauropod (Hudiesaurus sinojapanorum gen. et sp. nov.) from the Turpan Basin, China. Sino-Japanese Silk Road Dinosaur Expedition 102-110. China Ocean Press, Beijing. dong1997a
  2. Upchurch, P.; Mannion, P. D.; Xu, X.; Barrett, P. M. (2021). Re-assessment of the Late Jurassic eusauropod dinosaur Hudiesaurus sinojapanorum Dong, 1997, from the Turpan Basin, China, and the evolution of hyper-robust antebrachia in sauropods. Journal of Vertebrate Paleontology 41(4). Informa UK Limited. doi:10.1080/02724634.2021.1994414 upchurch2021a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b