English: Ampelognathus is a basal ornithopod dinosaur from the Late Cretaceous of Texas, in the United States. The name means "Grapevine jaw" after Grapevine Lake, where it was discovered. It is more derived than the Hypsilophodonts, and more basal than the Iguanodonts. The dentary of Ampelognathus generally resembles those in other small ornithopods, but is slightly twisted along its length so that the teeth in the back of the jaw pointed somewhat inward. Ampelognathus measured about 80 cm in length, and 2 kg im body mass.