Yixianosaurus
Named after the Yixian Formation of Liaoning, China where it was found, combined with Greek sauros meaning 'lizard'; translates as 'Yixian lizard'
Yixianosaurus is a maniraptoran theropod dinosaur genus from the Early Cretaceous of China.
Under dispute
There is no consensus on the position of Yixianosaurus longimanus, known from a shoulder girdle and forelimbs. Its describers placed it as a basal deinonychosaur; later studies have recovered it as a basal paravian (Foth and Rauhut, 2017), an anchiornithid close to Xiaotingia (Cau and colleagues, 2017; Wang and colleagues, 2023), a dromaeosaurid (Hartman and colleagues, 2019), and, under implied weighting, near the base of Pennaraptora (Foth and colleagues, 2025). It is placed conservatively at Maniraptora incertae sedis.
Diagnosis
- Manus 140% as long as humerus, longer than all other non-avian maniraptorans except Protarchaeopteryx and Epidendrosaurus
- Manual phalanx II22 longer than metacarpal II, a feature unique among maniraptorans except Epidendrosaurus
- Manual phalanx III23 244% as long as phalanx III21, the largest ratio among known maniraptorans
- Manual phalanx III22 bears a proximoventral heel, a feature shared with basal dromaeosaurs
- Scapula significantly shorter than humerus, a derived feature characteristic of Maniraptora
Species
Yixianosaurus longimanus Xu & Wang, 2003
Type species
From Latin 'longus' meaning 'long' and 'manus' meaning 'hand', referring to the animal's notably elongated hand, which is 140% of the length of the humerus.
- Holotype
- IVPP V12638 , Institute of Vertebrate Paleontology and Paleoanthropology
- Material
- Articulated remains of almost complete shoulder girdles and forelimbs, and some ribs with preserved integument.
- Horizon
- lower Yixian Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
- Locality
- Wangjiagou, Liaoning, China
References
- Xu, X.; Wang, X. L. (2003). A new maniraptoran dinosaur from the Early Cretaceous Yixian Formation of western Liaoning. Vertebrata PalAsiatica 41(3): 195-202. xu2003a
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Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.
Source of the hip height estimate, and the appearance features.
jones2026c -
Foth, C.; Rauhut, O. W. M. (2017). Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology 17(1). Springer Science and Business Media LLC. doi:10.1186/s12862-017-1076-y
Recovered Yixianosaurus as a basal paravian.
foth2017a -
Cau, A.; Beyrand, V.; Voeten, D. F. A. E.; Fernandez, V.; Tafforeau, P.; Stein, K.; Barsbold, R.; Tsogtbaatar, K.; Currie, P. J.; Godefroit, P. (2017). Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs. Nature 552(7685): 395-399. Springer Science and Business Media LLC. doi:10.1038/nature24679
Phylogenetic analysis recovered Yixianosaurus as an anchiornithid close to Xiaotingia.
cau2017a -
Foth, C.; van de Kamp, T.; Tischlinger, H.; Kantelis, T.; Carney, R. M.; Zuber, M.; Hamann, E.; Wallaard, J. J. W.; Lenz, N.; Rauhut, O. W. M.; Frey, E. (2025). A new Archaeopteryx from the lower Tithonian Mörnsheim Formation at Mühlheim (Late Jurassic). Fossil Record 28(1): 17-43. doi:10.3897/fr.28.131671
Recovered Yixianosaurus near the base of Pennaraptora under implied weighting.
foth2025a -
Wang, X.; Cau, A.; Wang, Z.; Yu, K.; Wu, W.; Wang, Y.; Liu, Y. (2023). A new theropod dinosaur from the Lower Cretaceous Longjiang Formation of Inner Mongolia (China). Cretaceous Research 151. Elsevier BV. doi:10.1016/j.cretres.2023.105605
Recovered Yixianosaurus as the sister of Xiaotingia within Avialae.
wang2023a -
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 Yixianosaurus within Dromaeosauridae.
hartman2019a