Classification: Ornithischia, Ornithopoda, Iguanodontidae
Genus: Iguanodon (“Iguana Tooth”)
Species: I. bernissartensis, I. anglicus, I. galvensis
Iguanodon ate plants, but exactly what kind of plants it ate remains a mystery. It was tall enough to eat from the branches of trees, but may also have feed on low growth vegetation.
The unique thumb spike of Iguanodon could have been used to ward off predators, or may have been helpful to break apart fruits and seeds for the Iguanodon to eat.
Some scientists believe Iguanodon may have traveled in herds, due to remains of many Iguanodons found in one spot. However, these dinosaurs may have died somewhere else, such as in a flash flood, and been transported to the same location.
While predatory dinosaurs such as Baryonyx and Concavenator lived around the same time and place as Iguanodon, its large size likely deterred these meat eaters from taking on a full grown Iguanodon. However, there is some evidence that Baryonyx may have preyed upon younger Iguanodons.
The most notable feature of Iguanodon were the cone-shaped spikes, one on each hand, where the thumb would be. Its exact function remains unknown.
Iguanodons could grow to over 30 feet, and possibly as long as 40 feet.
The first bones of Iguanodon to be discovered were teeth found in the 1820s, though there is some debate about who found them. The popular legend goes that they were found by Mary Ann Mantell, wife of doctor and paleontologist Gideon Mantell, while they were out on a stroll.
This was before scientists had any real understanding of what a “dinosaur” was, and many at the time dismissed the teeth as coming from a fish or a rhinoceros. It wasn’t until William Buckland – who had recently described Megalosaurus as the first named dinosaur – examined the teeth that he confirmed they belonged to a giant reptile. Naturalist Georges Cuvier, who had previously said they were likely rhino teeth, then decided they may have belonged to a large plant-eating reptile. The teeth, which resembled those of an iguana, led Gideon Mantell to settle on the name Iguanodon, making it the second named species of dinosaur.
Around ten years after the first discovery, a more complete specimen was found. The similarity of the teeth led Mantell to confirm that it was another Iguanodon. Initially, the large spike (which is now known to have been the dinosaur’s thumb) was placed on the nose as a horn. Statues of these incorrect Iguanodons were created and exhibited in London’s famous Crystal Palace Park.
In 1878, miners in Belgium happened upon a major discovery of at least 38 Iguanodon skeletons. These mostly complete remains gave a new understanding of Iguanodon, including the proper location of its thumb spike. Fossils from this find would be some of the first ever mounted dinosaur skeletons in museums.