In 1822, paleontologist Gideon Mantell unearthed a collection of strange teeth in Tilgate Forest in Sussex, England. Although aware that these teeth did not belong to any creature indigenous to southern England, Mantell spent the next three years struggling to classify the teeth; did they belong to a herbivore or a carnivore? A mammal or a reptile? Eventually, Mantell settled on the reptile, and more specifically on some gargantuan relative of the iguana. He named this new giant reptile “iguana-saurus,” meaning “iguana reptile,” but quickly changed the name to the more easily pronounced “Iguanodon.”

However, although this new retile had teeth, an immense bulk, and even a name, it still lacked a body.