Open Paleo

Sinusonasus

Xu & Wang, 2004 sih-NOO-soh-NAH-sus

From Latin 'sinus' (wave, curve, bay) + Latin 'nasus' (nose), meaning 'wavy nose' or 'sinuous nose', referring to the sinusoid (wave-like) form of the nasal bones in lateral view.

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

Sinusonasus is a genus of dinosaurs from the Early Cretaceous Period, recovered from the Yixian Formation. It lived in what is now the Liaoning Province of China. Sinusonasus was a theropod, specifically a troodontid dinosaur.

Under dispute

Sinusonasus is a basal troodontid whose grouping varies. Shen and colleagues (2017) and Pei and colleagues (2020) recover it within Sinovenatorinae, but other analyses place it outside that subfamily, often as the sister of Xixiasaurus (Xu and colleagues, 2012; Hartman and colleagues, 2019; Cau and Madzia, 2021; Sellés and colleagues, 2021; Kubota and colleagues, 2024).

Diagnosis

  1. Sinusoid nasal in lateral view
  2. Absence of a passage connecting the antorbital and maxillary fenestrae
  3. Relatively large teeth compared to other troodontids
  4. Plate-like chevrons forming a band-like structure along most of the tail
  5. Long neck between the femoral head and shaft

Species

Sinusonasus magnodens Xu & Wang, 2004

Type species

From Latin 'magnus' meaning 'large' and 'dens' meaning 'tooth', referring to the notably large middle maxillary teeth of this troodontid.

Holotype
IVPP V11527 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
An articulated skeleton missing the presacral vertebrae, shoulder girdles and forelimbs.
Horizon
Yixian Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
Lujiatun, Beipiao, Liaoning, China

Synonyms of the genus

Name Type Reason
Sinucerasaurus junior objective Not a separate taxon but a misspelling. A later paper by the same author rendered the genus as Sinucerasaurus, so the name carries the same type specimen as Sinusonasus.

References

  1. Xu, X.; Wang, X. (2004). A new troodontid (Theropoda: Troodontidae) from the Lower Cretaceous Yixian Formation of western Liaoning, China. Acta Geologica Sinica (English Edition) 78(1): 22-26. Wiley. doi:10.1111/j.1755-6724.2004.tb00671.x

    Named Sinusonasus as a troodontid.

    xu2004b
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026c
  3. Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ 7: e7247. PeerJ. doi:10.7717/peerj.7247

    Recovered Sinusonasus as the sister of Xixiasaurus, outside Sinovenatorinae.

    hartman2019a
  4. Shen, C.; Lü, J.; Liu, S.; Kundrát, M.; Brusatte, S. L.; Gao, H. (2017). A New Troodontid Dinosaur from the Lower Cretaceous Yixian Formation of Liaoning Province, China. Acta Geologica Sinica (English Edition) 91(3): 763-780. Wiley. doi:10.1111/1755-6724.13307

    Recovered Sinusonasus within Sinovenatorinae, as the sister of Daliansaurus.

    shen2017b
  5. Pei, R.; Pittman, M.; Goloboff, P. A.; Dececchi, T. A.; Habib, M. B.; Kaye, T. G.; Larsson, H. C. E.; Norell, M. A.; Brusatte, S. L.; Xu, X. (2020). Potential for Powered Flight Neared by Most Close Avialan Relatives, but Few Crossed Its Thresholds. Current Biology 30(20): 4033-4046.e8. Elsevier BV. doi:10.1016/j.cub.2020.06.105

    Recovered Sinusonasus within Sinovenatorinae.

    pei2020a
  6. Xu, X.; Zhao, Q.; Sullivan, C.; Tan, Q. W.; Sander, M.; Ma, Q. Y. (2012). The taxonomy of the troodontid IVPP V 10597 reconsidered. Vertebrata PalAsiatica 50(2): 140-150.

    Recovered Sinusonasus as the sister of a clade of derived troodontines.

    xu2012b
  7. Cau, A.; Madzia, D. (2021). The phylogenetic affinities and morphological peculiarities of the bird-like dinosaur Borogovia gracilicrus from the Upper Cretaceous of Mongolia. PeerJ 9: e12640. PeerJ. doi:10.7717/peerj.12640

    Recovered Sinusonasus as the sister of Sinornithoides.

    cau2021a
  8. Sellés, A. G.; Vila, B.; Brusatte, S. L.; Currie, P. J.; Galobart, À. (2021). A fast-growing basal troodontid (Dinosauria: Theropoda) from the latest Cretaceous of Europe. Scientific Reports 11(1). Springer Science and Business Media LLC. doi:10.1038/s41598-021-83745-5

    Recovered Sinusonasus as the sister of Xixiasaurus.

    sellés2021a
  9. Kubota, K.; Kobayashi, Y.; Ikeda, T. (2024). Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae. Scientific Reports 14(1). Springer Science and Business Media LLC. doi:10.1038/s41598-024-66815-2

    Recovered Sinusonasus as the sister of Xixiasaurus.

    kubota2024a