EdmontosaurusFOX.jpg|Edmontosaurus Saur.jpg|Saurolophus Hardosaurveleforms.png|Velafrons Hadrosauroids are a group of Ornithopod dinosaurs within Iguanodontia, and are most notable by having duck-shaped muzzles (hence their nickname "duckbills"). Hadrosaurs originated in the middle Cretaceous period and they died out by the end of the Mesozoic.