Dryosaurus

Dryosaurus ( , meaning 'tree lizard', Greek '''' () meaning 'tree, oak' and () meaning 'lizard' (the name reflects the forested habitat, not a vague oak-leaf shape of its cheek teeth as is sometimes assumed)) is an extinct genus of herbivorous ornithopod dinosaur that lived in the Late Jurassic period. It was an iguanodont (formerly classified as a hypsilophodont). Fossils have been found in the western United States and were first discovered in the late 19th century. Valdosaurus canaliculatus and Dysalotosaurus lettowvorbecki were both formerly considered to represent species of Dryosaurus.

==Description== thumb|left|Restoration of D. altus thumb|Size comparison of D. elderae with a human Based on known specimens, Dryosaurus has been estimated to have reached up to long and to have weighed up to . However, as no known adult specimens of the genus have been found, the adult size remains unknown. In 2018, the largest specimen (CM 1949) was concluded to be from another species; revising the identity of this specimen put the previous research on size and growth into question.