Open Paleo

Jeholosaurus

Xu et al., 2000 juh-HOH-lo-SAWR-us

Named after Jehol, a historical province in northeastern China (western Liaoning and northern Hebei), combined with Greek sauros (lizard); meaning 'Jehol lizard'

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

Jeholosaurus is a genus of small neornithischian dinosaur from the Early Cretaceous-aged Yixian Formation of what is now China.

Under dispute

Jeholosaurus is the type genus of Jeholosauridae, recovered as an early-diverging neornithischian (with Yueosaurus) stemward of Thescelosauridae and Cerapoda by Boyd (2015), Madzia and colleagues (2017), and Manitkoon and colleagues (2023). Fonseca and colleagues (2024) instead recover Jeholosaurus within Thescelosaurinae, rendering Jeholosauridae inapplicable.

Diagnosis

  1. Six premaxillary teeth (versus higher numbers in derived ornithopods)
  2. Few foramina on dorsal surface of nasal
  3. Large quadrate foramen on lateral side of quadratojugal
  4. Predentary about 1.5 times as long as premaxillary main body
  5. Anterior intercondylar groove of femur absent
  6. Metatarsals not in the same plane
  7. Pedal phalanx III-4 longer than other phalanges of pedal digit III
  8. Lack of external mandibular fenestra

Species

Jeholosaurus shangyuanensis Xu et al., 2000

Type species

Named for the geographical area of Shangyuan, where the fossil site is located.

Holotype
IVPP V12529 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
Nearly complete skull, partial postcrania.
Horizon
Yixian Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
Lujiatun, Shangyuan, Beipiao City, Liaoning, China

Notable specimens

  • IVPP V12530

    Institute of Vertebrate Paleontology and Paleoanthropology complementary

    Second specimen referred to the type species, preserving a better-preserved skull and some neck vertebrae. Its very large orbit (40% of skull length) and short snout, both cited as indicative of a juvenile, complement the compressed holotype skull.

    Xu et al. (2000)

References

  1. Xu, X.; Wang, X. L.; You, H. L. (2000). A primitive ornithopod from the Early Cretaceous Yixian Formation of Liaoning. Vertebrata PalAsiatica 38(4): 318-325. xu2000b
  2. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the body length and mass estimates, and the appearance features.

    paul2024a
  3. Manitkoon, S.; Deesri, U.; Khalloufi, B.; Nonsrirach, T.; Suteethorn, V.; Chanthasit, P.; Boonla, W.; Buffetaut, E. (2023). A New Basal Neornithischian Dinosaur from the Phu Kradung Formation (Upper Jurassic) of Northeastern Thailand. Diversity 15(7). MDPI AG. doi:10.3390/d15070851

    New basal neornithischian description supported Jeholosaurus's early-diverging Jeholosauridae placement.

    manitkoon2023a
  4. Fonseca, A. O.; Reid, I. J.; Venner, A.; Duncan, R. J.; Garcia, M. S.; Müller, R. T. (2024). A comprehensive phylogenetic analysis on early ornithischian evolution. Journal of Systematic Palaeontology 22: 2346577. doi:10.1080/14772019.2024.2346577

    Comprehensive ornithischian phylogeny recovered Jeholosaurus within Thescelosaurinae, not Jeholosauridae.

    fonseca2024a
  5. Madzia, D.; Boyd, C. A.; Mazuch, M. (2017). A basal ornithopod dinosaur from the Cenomanian of the Czech Republic. Journal of Systematic Palaeontology 16(11): 967-979. Informa UK Limited. doi:10.1080/14772019.2017.1371258

    Recovered Jeholosaurus as an early-diverging neornithischian stemward of Thescelosauridae and Cerapoda.

    madzia2017a
  6. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Treats Jeholosaurus as a basal neornithischian of Jeholosauridae.

    jones2026a
  7. Boyd, C. A. (2015). The systematic relationships and biogeographic history of ornithischian dinosaurs. PeerJ 3: e1523. PeerJ. doi:10.7717/peerj.1523

    Recovered Jeholosaurus as an early-diverging neornithischian.

    boyd2015a