Iguanodon

Iguanodon

Phylum : Chordata
Class : Reptilia
Superorder : Dinosauria
Order : †Ornithischia
Family : †Iguanodontidae
Genus : †Iguanodon

Length : 33ft (10m)
Weight : 10,000lbs (4,500kg)

Status : Extinct for around 110 million years

"Iguanodon" refers to several different discovered species within the genus Iguanodon. Theses Dinosaurs are notable because they were actually discovered before the word Dinosaur even existed! Around 1820 English geologist Gideon Mantell discovered a tooth of one of these guys in Sussex, England. He thought the tooth looked like a large Iguana tooth and the name stuck. Mantell continued to do research on Iguanodons and other fossilized species until his death in 1852.

Mantell's Iguanodon
 Teeth Illustration

Iguanodons were herbivores that lived in what is now Europe, Asia, and North America. The various species lived in the early Cretaceous, around 140-110 million years ago. They had three fingers on each hand, along with a thumb that had a hooked claw that could be used for grasping food and for defense. Iguanodon mouths had teeth in the back but none in the front. This was so they could tear apart plant materials with their beak-like mouths and then chew.

Iguanodons could move on all fours, but also on just their hind legs, due to the fact that their front limbs were only about 3/4 the size of the back limbs. They most likely moved in packs, like many modern herbivores do, and they laid eggs.