Hadrosauridae is a branch of the dinosaurs at the foot of a bird , a group of prosperous herbivorous dinosaurs, including the famous edmontosaurus, parasaurolophus fossils found in Asia, Europe, North America and Lower Cretaceous strata . They are the Upper Jurassic Iguanodon progeny class and have similar size. Hadrosaurid can be divided into two subfamilies. Lambeosaurinae has a large head crest or tubular, more lightweight body. Hadrosaurinae head crest or lack of tubular, few species have a hard crown, the larger body.