Open Paleo

Baiyinosaurus

Li et al., 2024 bye-YIN-oh-SAWR-us

From Baiyin (the city of Baiyin in Gansu Province, China, near where the fossils were found) + Greek sauros (σαῦρος) meaning 'lizard'; overall meaning 'Baiyin reptile'.

168.2–165.3 million years ago Bathonian, Middle Jurassic
Middle Jurassic stages

Baiyinosaurus is an extinct genus of stegosaurian dinosaurs from the Middle Jurassic Wangjiashan Formation of China. The genus contains a single species, B. baojiensis, known from a partial skeleton including cranial bones. The skeletal anatomy of Baiyinosaurus demonstrates transitional features between basal thyreophorans and stegosaurs. While many stegosaurs are known from China, Baiyinosaurus is the only one currently named from Gansu Province.

Diagnosis

  1. Frontal wider than long and contributes to both the medial and anterior margins of the supratemporal fenestra (unique among Stegosauria).
  2. Neural arches not greatly elongated dorsally: ratio of neural arch height to neural canal height is 1.59.
  3. Parapophyses well developed and project somewhat laterally on stalks in anterior view.
  4. Neural spines anteroposteriorly broad and axially expanded in lateral view: ratio of neural spine length to centrum length is 0.75.

Species

Baiyinosaurus baojiensis Li et al., 2024

Type species

References the type locality in the Baojishan Basin in the Qilian Mountains, Gansu Province, China.

Holotype
IVPG-D021 , Institute of Vertebrate Paleontology, Gansu Agricultural University
Material
Partial skeleton comprising a partial cranium, one cervical vertebra, seven dorsal vertebrae and one caudal vertebra.
Horizon
upper Straw-yellow Sandstone Member, Wangjiashan Formation, Bathonian, Middle Jurassic , 168.2–165.3 million years ago
Locality
Pingchuan District, Baiyin City, Gansu, China

References

  1. Li, N.; Maidment, S. C. R.; Li, D.; You, H.; Peng, G. (2024). A new stegosaur (Dinosauria: Ornithischia) from the Middle Jurassic of Gansu Province, China. Scientific Reports 14(1). Springer Science and Business Media LLC. doi:10.1038/s41598-024-66280-x li2024a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the body length, mass, and hip height estimates.

    jones2026a