>>57080181I'd honestly go as far to say that Iguanodon is probably one of the most important dinosaurs discovered. Its as old as the term paleontology itself.
While not the first described dinosaur, Megalosaurus was more of thought of as its name implies, just a "giant reptile" like a crocodile or komodo dragon since theropods were not known, so Megalosaurus didn't seem too unfamiliar at the time of discovery. Whereas Iguanodon was a large, terrestrial herbivorous reptile that had no such precedent until then and gave way to the idea that this was a group of unknown animals who didn't even have the name 'dinosaurs' yet and were a truly special group.