MEANING: Grapevine jaw
PERIOD: Late Cretaceous
CONTINENT: North America
Ampelognathus is a small basal ornithopod dinosaur. 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.
Abstract from paper: Sediments of the Woodbine Group exposed in northeastern Texas were deposited along the southwestern margin of Appalachia as a series of near-shore, shoreline, distal lowland swamp, lake, and fluvial deposits during a regression of the Western Interior Seaway in early and middle Cenomanian time. The Lewisville Formation (upper Woodbine Group) of north Texas preserves the most diverse terrestrial fossil assemblage known from Appalachia, but remains of small ornithischian dinosaurs have been conspicuously absent from it. An almost complete left dentary from the Lewisville Formation represents a new, small-bodied ornithopod taxon, Ampelognathus coheni gen. et sp. nov. The dentary is generally similar to those in non-iguanodontian ornithopods such as Hypsilophodon, Changchunsaurus, Haya, and Convolosaurus. Ampelognathus occupied an expected but previously missing component of the ‘mid’ Cretaceous terrestrial fauna of southwestern Appalachia. The growing diversity of fossil vertebrates and renewed paleobotanical study in the Lewisville Formation reinforces the importance of the unit’s fossil record for understanding eastern North American terrestrial ecosystems during an important transitional period in the earliest Late Cretaceous.
Ampelognathus is from the Cretaceous. The Cretaceous is a geological period that lasted from about 145 to 66 million years ago. It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, "chalk", which is abundant in the latter half of the period.
The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct flora and fauna, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread gymnosperm groups.
The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction that lies between the Mesozoic and Cenozoic Eras.
Ampelognathus is an ornithopod. Ornithopoda is a clade of ornithischian dinosaurs that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous. They dominated the North American continent, then spread to Asia and eventually the southern hemisphere toward the end of the Cretaceous. Their major evolutionary advantage was their batteries of teeth, which allowed them to process vegetation in an extremely efficient way. Ornithopods were a diverse group, and included the hadrosaurs, which continued to dominate until the Cretaceous–Paleogene extinction event, which wiped out all non-avian dinosaurs.