Open Paleo

Baminornis

Chen et al., 2025

"Bamin" (Mandarin), for Fujian Province, + "ornis" (Greek), bird

154.8–149.2 million years ago Kimmeridgian, Late Jurassic
Late Jurassic stages

Baminornis is an extinct genus of basal avialan known from the Upper Jurassic (Kimmeridgian age) Nanyuan Formation of China. The genus contains a single species, Baminornis zhenghensis, known from a partial skeleton. Baminornis was initially identified as the oldest known avialan to bear a fused pygostyle, but later research cast doubt on the identification of this structure, claiming it could instead be part of the synsacrum.

Diagnosis

  1. Fused pygostyle of five vertebrae that curves dorsally and is longer than metacarpal II
  2. Metacarpal I with an asymmetric ginglymoid distal articulation and an enlarged medial condyle
  3. Ungual of manual digit I about twice as large as that of digit III
  4. Ischium lacking both the obturator process and the posterior process
  5. Strut-like coracoid separated from the scapula, with a boomerang-shaped furcula whose interclavicular angle is 65 degrees
  6. Manual phalangeal formula 2-3-4, with metacarpal III extending further distally than metacarpal II and digit III shorter than metacarpal III

Species

Baminornis zhenghensis Chen et al., 2025

Type species

"zhenghe" (Mandarin), for Zhenghe County, where the holotype was found

Holotype
IVPP V33259 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
Incomplete, partially articulated skeleton including the pygostyle and caudal vertebrae, dorsal vertebrae and ribs, gastralia, furcula, scapulae, coracoids, humerus, radius, ulna, manus, ilium, ischium, pubes, femur, tibiae and fibula
Horizon
lower Nanyuan Formation, Kimmeridgian, Late Jurassic , 154.8–149.2 million years ago
Locality
near Yangyuan Village, Zhenghe, Fujian, China Chen and colleagues (2025) place the holotype in layer 2 of the excavation site, with that of Fujianvenator. Xu and colleagues (2023) bracket that layer with zircon ages of 150.2 ± 1.1 Ma below and 149.9 ± 1.1 Ma above, both Kimmeridgian on the ICS chart v2024/12 at their central values; the "Tithonian stage" both papers give belongs to an older chart.

References

  1. Chen, R.; Wang, M.; Dong, L.; Zhou, G.; Xu, X.; Deng, K.; Xu, L.; Zhang, C.; Wang, L.; Du, H.; Lin, G.; Lin, M.; Zhou, Z. (2025). Earliest short-tailed bird from the Late Jurassic of China. Nature 638(8050): 441-448. doi:10.1038/s41586-024-08410-z chen2025a
  2. Huang, J.; Wang, X.; Cau, A.; Mao, L.; Liu, Y.; Wang, Y. (2025). A new euornithine from the Lower Cretaceous (Aptian) of China reveals the first radiation of fish-eating birds. Cretaceous Research 179: 106244. doi:10.1016/j.cretres.2025.106244

    Codes the purported pygostyle as unknown, since the fused vertebrae could be part of the sacral series, and still recovers Baminornis as the sister taxon of Jeholornithiformes plus Pygostylia.

    huang2025a
  3. Xu, L.; Wang, M.; Chen, R.; Dong, L.; Lin, M.; Xu, X.; Tang, J.; You, H.; Zhou, G.; Wang, L.; He, W.; Li, Y.; Zhang, C.; Zhou, Z. (2023). A new avialan theropod from an emerging Jurassic terrestrial fauna. Nature 621(7978): 336-343. Springer Science and Business Media LLC. doi:10.1038/s41586-023-06513-7

    Dates the layer of the Nanyuan Formation that yielded the holotype.

    xu2023a