Open Paleo

Beipiaosaurus

Xu et al., 1999 bay-pyow-SAWR-us /ˌbeɪpjaʊˈsɔːrəs/

Named for Beipiao City in Liaoning Province, China, where the fossils were found, combined with Greek 'sauros' meaning 'lizard'.

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

Beipiaosaurus is a genus of therizinosauroid theropod dinosaurs that lived in China during the Early Cretaceous in the Yixian Formation. The first remains were found in 1996 and formally described in 1999. Before the discovery of Yutyrannus, Beipiaosaurus were among the heaviest dinosaurs known from direct evidence to be feathered. Beipiaosaurus is known from three reported specimens. Numerous impressions of feather structures were preserved that allowed researchers to determine the feathering color which turned out to be brownish.

Diagnosis

  1. Shorter and more bulbous tooth crowns than other therizinosauroids
  2. Tridactyl pes with a splint-like proximal first metatarsal (metatarsal I does not contact the tarsus)
  3. Shallow anterior iliac process
  4. Long manus approximately 10% longer than the femur
  5. Elongated lateral articular surface on the palmar side of manual phalanx I-1
  6. Proximally compressed metatarsals III and IV

Species

Beipiaosaurus inexpectus Xu et al., 1999

Type species

From Latin 'inexpectus' meaning 'unexpected', referring to the surprising features found in this animal.

Holotype
IVPP V11559 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
Nearly complete skeleton including partial right dentary with dentition, postorbital, parietal, nasal, prootic, cervicals and dorsals, incomplete caudal, ribs, scapula, coracoids, furcula, partial humerus, radius, ulna, nearly complete hands, partial ilium, pubis, ischium, complete right femur, right tibia and fibula, incomplete left femur, tibia and fibula, and incomplete right foot.
Horizon
Jianshangou Member, Yixian Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
Sihetun, Liaoning, China

Notable specimens

  • STM 31-1

    Shandong Tianyu Museum of Nature exceptional preservation

    Referred partial skeleton with complete skull, neck, and torso preserving an extensive covering of unique elongated broad filamentous feathers (EBFFs), first described in 2009. Later yielded keratin-rich corneocytes in fossilized skin flakes under electron microscopy.

    Xu et al. (2009)

  • BMNHC PH000911

    Beijing Museum of Natural History exceptional preservation

    Referred partial individual from Sihetun with filamentous feather impressions preserved around the neck. Melanosome analysis of these feathers found sphere-shaped melanosomes indicating a dark brownish coloration.

    Li et al. (2014)

References

  1. Xu, X.; Tang, Z. L.; Wang, X. L. (1999). A therizinosauroid dinosaur with integumentary structures from China. Nature 399(6734): 350-354. Springer Science and Business Media LLC. doi:10.1038/20670 xu1999b
  2. Wang, Y.; Olsen, P. E.; Sha, J.; Yao, X.; Liao, H.; Pan, Y.; Kinney, S.; Zhang, X.; Rao, X. (2016). Stratigraphy, correlation, depositional environments, and cyclicity of the Early Cretaceous Yixian and ?Jurassic-Cretaceous Tuchengzi formations in the Sihetun area (NE China) based on three continuous cores. Palaeogeography, Palaeoclimatology, Palaeoecology. Elsevier BV.

    Raises the Jianshangou to member rank and places the Sihetun exposures that produced the holotype within it.

    wang2016a
  3. Xu, X.; Zheng, X.; You, H. (2009). A new feather type in a nonavian theropod and the early evolution of feathers. Proceedings of the National Academy of Sciences 106(3): 832-834. doi:10.1073/pnas.0810055106 xu2009b
  4. Li, Q.; Clarke, J. A.; Gao, K. Q.; Zhou, C. F.; Meng, Q.; Li, D.; D'Alba, L.; Shawkey, M. D. (2014). Melanosome evolution indicates a key physiological shift within feathered dinosaurs. Nature 507(7492): 350-353. doi:10.1038/nature12973 li2014b
  5. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the appearance features.

    paul2024a