Open Paleo

Mei

Xu & Norell, 2004 MY

From Chinese 寐 (mèi) meaning 'sleepy' or 'soundly sleeping', referring to the sleeping posture in which the holotype specimen was preserved.

125.8–121.4 million years ago Barremian, Early Cretaceous
Early Cretaceous stages

Mei is a genus of duck-sized troodontid dinosaur first unearthed by paleontologists from the Yixian Formation in Liaoning, China in 2004. Mei lived during the Early Cretaceous period.

Diagnosis

  1. Extremely large nares extending posteriorly over one-half of the maxillary tooth row
  2. Closely packed middle maxillary teeth
  3. Maxillary tooth row extending posteriorly to the level of the preorbital bar
  4. Robust, sub-'U'-shaped furcula
  5. Lateral process on distal tarsal IV
  6. Proximal end of the pubic shaft significantly compressed anteroposteriorly, extending laterally just ventral to ilium articulation

Species

Mei long Xu & Norell, 2004

Type species

From Mandarin Chinese 'long' (龍) meaning 'dragon', combining with the genus name 'mei' (寐, 'soundly sleeping') to give the full meaning 'soundly sleeping dragon', in reference to the sleeping posture of the holotype.

Holotype
IVPP V12733 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
A nearly complete, fully articulated skeleton.
Horizon
Lujiatun Member, Yixian Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
Lujiatun, Shangyuan, Beipiao City, Liaoning, China The describing paper gives the horizon as the "lowest more fluvial, volcaniclastic beds of Yixian Formation" and discusses the specimen's burial among the vertebrates "collected from the Lujiatun beds".

References

  1. Xu, X.; Norell, M. A. (2004). A new troodontid dinosaur from China with avian-like sleeping posture. Nature 431(7010): 838-841. Springer Science and Business Media LLC. doi:10.1038/nature02898

    Gives the locality as Lujiatun, Shangyuan, Beipiao City, and the horizon as the lowest beds of the formation.

    xu2004c
  2. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the body length and mass estimates.

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

    Source of the hip height estimate.

    jones2026c
  4. Zhong, Y.; Huyskens, M. H.; Yin, Q. Z.; Wang, Y.; Ma, Q.; Xu, Y. G. (2021). High-precision geochronological constraints on the duration of 'Dinosaur Pompeii' and the Yixian Formation. National Science Review 8(6): nwab063. doi:10.1093/nsr/nwab063

    Dates the base of the Yixian Formation, the Lujiatun Unit that yielded the holotype, to 125.755 Ma: Barremian on the ICS chart v2024/12 at its central value; its error reaches the Hauterivian.

    zhong2021a
  5. Gale, A. S.; Mutterlose, J.; Batenburg, S.; Gradstein, F. M.; Agterberg, F. P.; Ogg, J. G.; Petrizzo, M. R. (2020). The Cretaceous Period. Geologic Time Scale 2020 (Gradstein, F. M.; Ogg, J. G.; Schmitz, M. D.; Ogg, G. M., eds) 1023-1086. Elsevier, Amsterdam. doi:10.1016/B978-0-12-824360-2.00027-9

    Gives the GTS2020 Barremian span, 126.5 to 121.4 Ma; the ICS chart v2024/12 starts the stage at 125.77 Ma.

    gale2020a