Open Paleo

Haya

Makovicky et al., 2011 hah-yah

From Sanskrit 'haya', referring to the Hayagriva avatar of Vishnu (depicted with a horse head), in reference to the elongate horse-like skull and the deity's appearance in the Buddhist art of Mongolia.

85.7–72.2 million years ago Santonian–Campanian, Late Cretaceous
Late Cretaceous stages

Haya is an extinct genus of basal neornithischian dinosaur known from the Late Cretaceous of Mongolia.

Under dispute

Haya is recovered within Thescelosaurinae by Boyd (2015) and Fonseca and colleagues (2024). Its describers recovered it as the sister of Jeholosaurus and Changchunsaurus in a largely unresolved Neornithischia (Makovicky and colleagues, 2011), Herne and colleagues (2019) placed it in Jeholosauridae, and Barta and Norell (2021) could not resolve it between Thescelosaurinae and Orodrominae.

Diagnosis

  1. Five homodont, bulbous, unserrated premaxillary teeth
  2. Triangular accessory maxillary fenestra present (as in Hypsilophodon)
  3. Jugal with bifid caudal ramus (as in Jeholosaurus)
  4. Quadratojugal foramen large, piercing quadratojugal
  5. Midline depression along internasal suture between base of internarial bar and widest point across nasals
  6. Predentary arrow-shaped with bifid ventral ramus (as in Changchunsaurus)

Species

Haya griva Makovicky et al., 2011

Type species

From the Sanskrit 'Hayagriva', the horse-headed avatar of the Hindu god Vishnu, in reference to the elongate horse-like skull of Haya and the appearance of this deity in the Buddhist art of Mongolia.

Holotype
IGM 100/2017 , Paleontological Center, Mongolian Academy of Sciences
Material
Complete, barely distorted skull and anterior cervical series
Horizon
middle Javkhlant Formation, Santonian–Campanian, Late Cretaceous , 85.7–72.2 million years ago
Locality
Khugenetjavkhlant, Dornogovi, Mongolia

References

  1. Makovicky, P. J.; Kilbourne, B. M.; Sadleir, R. W.; Norell, M. A. (2011). A new basal ornithopod (Dinosauria, Ornithischia) from the Late Cretaceous of Mongolia. Journal of Vertebrate Paleontology 31(3): 626-640. Informa UK Limited. doi:10.1080/02724634.2011.557114

    Named Haya and recovered it as the sister of Jeholosaurus and Changchunsaurus.

    makovicky2011a
  2. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the body length and mass estimates.

    paul2024a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026a
  4. Herne, M. C.; Nair, J. P.; Evans, A. R.; Tait, A. M. (2019). New small-bodied ornithopods (Dinosauria, Neornithischia) from the Early Cretaceous Wonthaggi Formation (Strzelecki Group) of the Australian-Antarctic rift system, with revision of Qantassaurus intrepidus Rich and Vickers-Rich, 1999. Journal of Paleontology 93(3): 543-584. Cambridge University Press (CUP). doi:10.1017/jpa.2018.95

    Placed Haya in Jeholosauridae among small-bodied Early Cretaceous ornithopods.

    herne2019a
  5. 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 recovering Haya within Thescelosaurinae.

    fonseca2024a
  6. Barta, D. E.; Norell, M. A. (2021). The Osteology of Haya griva (Dinosauria: Ornithischia) from the Late Cretaceous of Mongolia. Bulletin of the American Museum of Natural History 445(1): 1-112. doi:10.1206/0003-0090.445.1.1

    Could not resolve Haya between Thescelosaurinae and Orodrominae in their phylogenetic analysis.

    barta2021a
  7. Boyd, C. A. (2015). The systematic relationships and biogeographic history of ornithischian dinosaurs. PeerJ 3: e1523. PeerJ. doi:10.7717/peerj.1523

    Recovered Haya within Thescelosaurinae.

    boyd2015a