Iguanodon was a massive herbivorous long-tailed bipedal dinosaur of the genus Iguanodon, common in Europe and N Africa in Jurassic and Cretaceous times: suborder Ornithopoda (ornithopods). They were bulky and could shift from bipedality to quadrupedality. Named in 1825 by English geologist Gideon Mantell, Iguanodon was the second type of dinosaur formally named, after Megalosaurus. The numerous specimens of this genus, including nearly complete skeletons from two well-known bonebeds, have allowed researchers to make informed hypotheses regarding many aspects of the living animal, including feeding, movement, and social behavior. The word dinosaur was coined by Richard Owen in 1841, deinos (terrible) + sauros (lizard) which describe various extinct reptiles of the orders Saurischia and Ornithischia that flourished during the Mesozoic Era. Dinosaurs were carnivorous or herbivorous, dwelled mostly on land, and varied from the size of a small dog to the largest land animals that ever lived. Photograph originally captioned: Iguanodon skeleton found in a coal mine at Bernissart, Belgium in 1878.