Open Paleo

Bienosaurus

Dong, 2001 bee-EN-oh-SOR-us Nomen dubium

From the surname Bien (in honor of M. N. Bien, collector of the holotype) plus Greek sauros ('lizard'); meaning 'Bien's lizard'.

201.4–192.9 million years ago Hettangian–Sinemurian, Early Jurassic
Early Jurassic stages

Bienosaurus is a dubious genus of thyreophoran dinosaur from the Early Jurassic (probably Hettangian to Sinemurian) Lower Lufeng Formation of Yunnan Province in China.

Under dispute

Bienosaurus is a nomen dubium based on a fragmentary lower jaw from the Early Jurassic of China; reassessment found no diagnostic features and identified it as an indeterminate early-diverging thyreophoran, possibly synonymous with Tatisaurus (Raven and colleagues, 2019; Jones, 2026).

Species

Bienosaurus lufengensis Dong, 2001 Nomen dubium

Type species

From Lufeng (the Lufeng Basin, where the holotype was found) and Latin -ensis ('from'); meaning 'from Lufeng'.

Holotype
IVPP V15311 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
Nearly complete right lower jaw, fragmentary frontal, and other cranial fragments.
Notes
Originally cataloged by Dong as IVPP V 9612, but Raven and colleagues (2019) reassigned the specimen to IVPP V15311 because V 9612 was already in use for the holotype of Sinornithoides youngi.
Horizon
Zhangjiawa Member, Lufeng Formation, Hettangian–Sinemurian, Early Jurassic , 201.4–192.9 million years ago
Locality
Lufeng Basin, Yunnan, China

References

  1. Dong, Z. (2001). Primitive armored dinosaur from the Lufeng Basin, China. Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie (Tanke, D. H.; Carpenter, K., eds.) 237-242. Indiana University Press, Bloomington. dong2001b
  2. Raven, T. J.; Barrett, P. M.; Xu, X.; Maidment, S. C. R. (2019). A reassessment of the purported ankylosaurian dinosaur Bienosaurus lufengensis from the Lower Lufeng Formation of Yunnan, China. Acta Palaeontologica Polonica 64(2): 335-342. doi:10.4202/app.00577.2018

    Reassessment concluding Bienosaurus lufengensis is a nomen dubium and an indeterminate basal thyreophoran, not an ankylosaurian; corrects the holotype catalog number from V 9612 to V15311.

    raven2019a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Treats Bienosaurus as a nomen dubium, possibly synonymous with Tatisaurus.

    jones2026a
  4. Irmis, R. B.; Knoll, F. (2008). New ornithischian dinosaur material from the Lower Jurassic Lufeng Formation of China. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 247(1): 117-128. doi:10.1127/0077-7749/2008/0247-0117

    Equates the Lufeng "deep red beds" with the Zhangjiawa Member of Fang and colleagues.

    irmis2008a