Open Paleo

Ampelognathus

Tykoski et al., 2023 am-pell-o-nath-us

From Greek 'ampelos' meaning 'grapevine' and 'gnathos' meaning 'jaw'; meaning 'grapevine jaw', named in reference to Grapevine Lake where the holotype was found

100.5–93.9 million years ago Cenomanian, Late Cretaceous
Late Cretaceous stages

Ampelognathus is an extinct genus of possibly rhabdodontomorph ornithopod dinosaurs from the Late Cretaceous (Cenomanian) Lewisville Formation of Texas. The type species is Ampelognathus coheni.

Under dispute

Ampelognathus coheni was described as a non-iguanodontian ornithopod, the sister of Thescelosaurus plus Iguanodontia, a position its describers found weakly supported (Tykoski and colleagues, 2023). Czepiński and Madzia (2025) instead recover it in a basal polytomy within Rhabdodontomorpha under implied weighting, its precise placement uncertain.

Diagnosis

  1. Approximately 45° counter-clockwise torsion of middle and posterior dentary sections relative to anterior part, resulting in dorsomedial orientation of posterior alveoli axes (autapomorphy)
  2. No diastema between predentary contact and first dentary alveolus
  3. Coronoid process low, so dentary height at process is less than 150% mandibular height under mid-part of tooth row
  4. 16 Dentary tooth positions, representing a relatively high tooth count for the size of the dentary

Species

Ampelognathus coheni Tykoski et al., 2023

Type species

Named for Murray Cohen, the discoverer of the holotype specimen.

Holotype
DMNH 2021-05-02 , Perot Museum of Nature and Science
Material
Single, nearly-complete left dentary
Horizon
Lewisville Formation, Cenomanian, Late Cretaceous , 100.5–93.9 million years ago
Locality
Grapevine Lake emergency spillway, Texas, United States

References

  1. Tykoski, R. S.; Contreras, D. L.; Noto, C. (2023). The first small-bodied ornithopod dinosaur from the Lewisville Formation (middle Cenomanian) of Texas. Journal of Vertebrate Paleontology 43(2). Informa UK Limited. doi:10.1080/02724634.2023.2257238

    Named Ampelognathus and recovered it as the sister of Thescelosaurus plus Iguanodontia, with low support.

    tykoski2023a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the body length, mass, and hip height estimates.

    jones2026a
  3. Czepiński, Ł.; Madzia, D. (2025). Exploring the diversity and disparity of rhabdodontomorph ornithopods from the Late Cretaceous European archipelago. Scientific Reports 15(1). Springer Science and Business Media LLC. doi:10.1038/s41598-025-98083-z

    Recovered Ampelognathus in a basal polytomy within Rhabdodontomorpha under implied weighting.

    czepiński2025a