Open Paleo

Zhongyuansaurus

Xu et al., 2007 johng-YWEN-SAWR-us Disputed

Zhongyuan lizard

121.4–100.5 million years ago Aptian–Albian, Early Cretaceous
Early Cretaceous stages

Zhongyuansaurus is an extinct genus of ankylosaurid dinosaurs known from the Early Cretaceous Haoling Formation of what is now Henan Province, China. The genus contains two species, Z. luoyangensis, named in 2007, and Z. junchangi, named in 2025, each known from a single partial skeleton. Zhongyuansaurus is similar to Gobisaurus, and Arbour and Currie (2015) treated the two as synonyms.

Under dispute

The validity of Zhongyuansaurus is contested. Arbour and Currie (2015) found its remains indistinguishable from Gobisaurus and treated it as a junior synonym, a view followed by Jones (2026). Zhang and colleagues (2025) reject the synonymy, citing a longer tooth row (31.7% of skull length against 26.7% in Gobisaurus) and a straight rather than arched preorbital profile, and name a second species, Z. junchangi. Arbour and Currie (2015) group it, as Gobisaurus, with Shamosaurus in Shamosaurinae; Zhang and colleagues (2025) assign it only to Ankylosauridae.

Diagnosis

  1. Frontonasal region rugose, with irregular cranial ornamentation not divisible into distinct caputegulae
  2. Longitudinal groove on the dorsal surface of the premaxilla (also in Shamosaurus)
  3. Squamosal horn shorter and more rounded than in Crichtonpelta
  4. Preorbital region straight in lateral view (arched in Shamosaurus and Gobisaurus)
  5. Tooth row 31.7% of skull length (40% in Shamosaurus, 26.7% in Gobisaurus)

Species (2)

Zhongyuansaurus luoyangensis Xu et al., 2007 Disputed

Type species

Refers to the fossil locality in Ruyang County, which is administratively assigned to the Luoyang region (Henan Province, China).

Holotype
HGM 41HIII-0002 , Henan Geological Museum
Material
Nearly complete skull with partial mandible; dorsal and cervical neural arches; dorsal vertebral centra; middle and posterior caudal vertebral centra; 7 fused terminal caudal vertebrae; complete left humerus; left and right ischia; one pubis; osteoderms; dorsal ribs.
Horizon
Haoling Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
Locality
Liudian Township, Henan, China Xu and colleagues (2007) and Arbour and Currie (2015) give the Mangchuan Formation, which Lü and colleagues (2013) divide into the Xiahedong, Haoling and Shangdonggou formations. Zhang and colleagues (2025) place the holotype in the upper Haoling Formation.

Zhongyuansaurus junchangi Zhang et al., 2025

Honors Lü Junchang, the late Chinese vertebrate paleontologist who contributed to paleontological research in Henan.

Holotype
HGM 41HIII-0708 , Henan Geological Museum
Material
Right mandible; 14 caudal vertebrae; 7 fused terminal caudal vertebrae forming the tail club handle; 4 ribs; 10 haemal arches; left humerus; right metatarsal II; 41 osteoderms.
Horizon
upper Haoling Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
Locality
Zhongwa Village, Liudian Township, Ruyang County, Henan, China
Diagnosis
  1. At least five swallowtail-shaped, imbricate osteoderms in the tail region
  2. Small osteoderms attached to the surface of the tail club handle (absent in Z. luoyangensis)
  3. Ratio of humeral shaft circumference to humeral length 0.46 (0.55 in Z. luoyangensis)

References

  1. Xu, L.; Lü, J.; Zhang, X.; Jia, S.; Hu, W.; Zhang, J.; Wu, Y.; Ji, Q. (2007). [A new nodosaurid ankylosaur from the Cretaceous of Ruyang, Henan Province]. Acta Geologica Sinica 81(4): 433-438. xu2007a
  2. Arbour, V. M.; Currie, P. J. (2015). Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs. Journal of Systematic Palaeontology 14(5): 385-444. Informa UK Limited. doi:10.1080/14772019.2015.1059985

    Found Zhongyuansaurus indistinguishable from Gobisaurus and treated it as a junior synonym.

    arbour2015a
  3. 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

    Divides the Mangchuan Formation of the Ruyang Basin into the Xiahedong, Haoling and Shangdonggou formations.

    lü2013b
  4. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Treats Zhongyuansaurus as a synonym of Gobisaurus.

    jones2026a
  5. Zhang, J.; Jia, L.; Xu, L.; You, H.; Gao, D.; Liu, D.; Li, Y.; Wang, Y. (2025). New ankylosaurid material from the Lower Cretaceous of the Ruyang Basin, Henan Province. Acta Palaeontologica Sinica 64(1): 60-73. doi:10.19800/j.cnki.aps.2023037

    Names Z. junchangi, revises the genus diagnosis, and rejects the synonymy with Gobisaurus on tooth-row length and a straight preorbital profile; places both species in the upper Haoling.

    zhang2025z