Open Paleo

Sinosauropteryx

Ji & Ji, 1996 SIEN-o-saw-ROP-te-riks

From Latin/Greek 'Sino-' meaning 'Chinese', Greek 'sauros' meaning 'reptile' or 'lizard', and 'pteryx' meaning 'wing'; meaning 'Chinese reptilian wing.'

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

Sinosauropteryx is an extinct genus of coelurosaurian theropod dinosaurs. Described in 1996, it was the first dinosaur taxon outside of Avialae (birds and their immediate relatives) to be found with evidence of feathers. It was covered with a coat of very simple filament-like feathers. Structures that indicate the color pattern have also been preserved in some of its feathers, which show that Sinosauropteryx had a countershading pattern in its body with a banded tail. The reddish brown coloration previously inferred for Sinosauropteryx is based on the melanosomes preserved in the specimen of a separate genus, Huadanosaurus. Some contention has arisen with an alternative interpretation of the filamentous impression as remains of collagen fibers, but this has not been widely accepted.

Diagnosis

  1. Extremely short, primitive, uniform feathers unlike later avian forms
  2. Over 50 extremely elongated caudal vertebrae constituting 60% of body length
  3. Forelimb extremely short (approximately two-fifths hind limb length) with short thick humerus (~20 mm)
  4. Relatively high, blunt-rostrum skull with elliptical but not enlarged antorbital fenestra
  5. Robust acute dentition with over 50 extremely developed teeth
  6. Long robust hind limb with unfused proximal metatarsals and tarsals separated

Species

Sinosauropteryx prima Ji & Ji, 1996

Type species

From Latin 'prima' meaning 'first', in reference to its status as the first feathered non-avian dinosaur species discovered.

Holotype
GMV 2123, NIGP 127586 , National Geological Museum of China
Material
A relatively complete skeleton with approximately 65 cm total length, nearly triangular skull over 6 cm long, 54 caudal vertebrae, short forelimb with humerus ~20 mm, long robust hind limb with femur 53 mm and tibia ~60 mm, feathers on skull apex, cervical, dorsal, and caudal regions.
Notes
GMV 2123 is the holotype (main slab); the NIGP 127586 slab is its counterpart, housed at the Nanjing Institute of Geology and Palaeontology.
Horizon
Anjiagou Bed, Jianshangou Member, Yixian Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
Jianshangou-Sihetun area, Liaoning, China

Notable specimens

  • NIGP 127587

    Nanjing Institute of Geology and Palaeontology, Academia Sinica (NIGPAS) reproductive

    Referred specimen preserving several small unlaid eggs in the abdomen, two just in front of and above the pubic boot, proving the animal a female and suggesting it had dual oviducts and laid eggs in pairs like other theropods. The same specimen also preserved a lizard in its gut region.

    Chen et al. (1998)

References

  1. Chen, P.; Dong, Z.; Zhen, S. (1998). An exceptionally well-preserved theropod dinosaur from the Yixian Formation of China. Nature 391: 147-152. doi:10.1038/34356 chen1998a
  2. Ji, Q.; Ji, S. (1996). [On discovery of the earliest bird fossil in China and the origin of birds]. Chinese Geology 10(233): 30-33. ji1996a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026c
  4. 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 bed to member rank and places the holotype in its Anjiagou Bed.

    wang2016a