Ruyangosaurus
Named for Ruyang County in Henan Province, China where it was discovered, combined with Greek '-saurus' meaning 'lizard'.
Ruyangosaurus is a genus of titanosauriform sauropod dinosaur recovered from the Early Cretaceous Haoling Formation of China. The type species is R. giganteus, described in 2009 by Lü Junchang and colleagues
Under dispute
The position of Ruyangosaurus is uncertain. It was described as a titanosauriform and tentatively referred to the basal titanosaur family Andesauridae (Lü and colleagues, 2009). Mannion and colleagues (2019) recovered it as a 'basal' titanosaur under equal weights but as a non-titanosaurian euhelopodid under implied weighting, leaving its titanosaurian versus somphospondylan affinities unresolved.
Diagnosis
- Relatively small neural canal and short neural spines
- Large, irregularly triangular deep fossa (postparapophyseal fossa) on the lateral surface of the neural arch
- Lack of centroprezygapophyseal lamina
- Two spinodiapophyseal laminae and the diapophysis form a deep concavity on the lateral surface of the base of the neural spine
- Posterior centrodiapophyseal lamina stoutest among the laminae
- Centropostzygapophyseal lamina weak and plate-like, forming a triangular concavity with the postzygodiapophyseal lamina and posterior centrodiapophyseal lamina
Species
Ruyangosaurus giganteus Lü et al., 2009
Type species
From Latin 'giganteus' meaning 'gigantic', referring to the enormous size of this titanosauriform sauropod.
- Holotype
- HGM 41HIII-0003 , Henan Geological Museum
- Material
- Nearly complete posterior cervical vertebra, nearly complete posterior dorsal vertebra, posterior cervical rib, anterior dorsal rib, proximal portion of right femur, complete right tibia.
- Notes
- The describing paper prints the catalog number as 41HIII-0002, which is the number of the Zhongyuansaurus luoyangensis holotype printed two years earlier. A photograph Nair (2026) posted shows 41HIII-0003 inscribed on the material, an inscription absent from the describing paper's figure and so probably added after 2009.
- Horizon
- Haoling Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
- Locality
- Shengshuigou, Shaping village, Henan, China
References
-
Lü, J. C.; Xu, L.; Jia, S. H.; Zhang, X. L.; Zhang, J. M.; Yang, L. L.; You, H. L.; Ji, Q. (2009). A new gigantic sauropod dinosaur from the Cretaceous of Ruyang, Henan, China. Geological Bulletin of China 28(1): 1-10.
Erects the species and gives the unit as the Mangchuan Formation.
lü2009a -
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.
Source of the hip height estimate.
jones2026b -
Nair, J. (2026). Z. luoyangensis vs. R. giganteus holotype specimen numbers. Dinosaur Mailing Group. https://groups.google.com/g/dinosaurmailinggroup/c/jDmAAvNjIzw/m/Dm2O6a17AwAJ
Posts a photograph of the material showing the inscribed number HGM 41HIII-0003, and judges that the correct number "probably is HGM 41HIII-0003, not "0002"".
nair2026a -
Mannion, P. D.; Upchurch, P.; Jin, X.; Zheng, W. (2019). New information on the Cretaceous sauropod dinosaurs of Zhejiang Province, China: impact on Laurasian titanosauriform phylogeny and biogeography. Royal Society Open Science 6(8): 191057. doi:10.1098/rsos.191057
Rescored Ruyangosaurus; recovered as a 'basal' titanosaur under equal weights and a non-titanosaurian euhelopodid under implied weighting.
mannion2019b -
Lü, J.; Xu, L.; Pu, H.; Zhang, X.; Zhang, Y.; Jia, S.; Chang, H.; Zhang, J.; Wei, X. (2013). A new sauropod dinosaur (Dinosauria, Sauropoda) from the late Early Cretaceous of the Ruyang Basin (central China). Cretaceous Research 44: 202-213. Elsevier BV. doi:10.1016/j.cretres.2013.04.009
Reports the Mangchuan Formation subdivided into the Xiahedong, Haoling and Shangdonggou formations, and places the Ruyang Basin dinosaurs, this species among them, in the Haoling.
lü2013b