Iguanodon meaning "Iguana Tooth" is a genus of iguanodontid ornithopod dinosaur that lived between 126 and 122 million years ago, during the Early Cretaceous in what is now Europe. Many of the species found around the world have been classified in the genus Iguanodon, dating from the Late Jurassic to the Early Cretaceous, the taxonomic review of the early 21st century has defined Iguanodon as being based on a single well-founded species.
Iguanodon was a large and bulky herbivore, measuring between 9 and 11 meters in length and 4.5 tons in body mass. Distinctive features include large spikes on the thumb, possibly used for defense against predators, combined with long prehensile fifth fingers capable of foraging for food.
The genus was named in 1825 by the English geologist Gideon Mantell, but discovered by William Harding Bensted based on fossil specimens found in England and given the name anglicus. Iguanodon was the second type of dinosaur to be named based on fossil specimens, after Megalosaurus. Along with Megalosaurus and Hylaeosaurus, it was one of the three genera originally used to define Dinosauria. The genus Iguanodon belongs to the larger group Iguanodontia, along with the duck-billed hadrosaurs. The taxonomy of this genus continues to be a subject of study.
In 1878 new and much more complete remains of Iguanodon were discovered in Belgium, which were studied by Louis Dollo. These were assigned the new species. In the early 21st century, the remains named Iguanodon in England were understood to belong to four different species that were not closely related to each other, which were later divided into Mantellisaurus, Barilium and Hypselospinus.
Iguanodon was one of the first dinosaurs to be scientifically described. Its name means "iguana tooth" due to the similarity of its teeth to those of modern iguanas.
Iguanodon lived during the Jurassic and Cretaceous periods, and fed primarily on plants, such as leaves and branches. Its varied diet allowed it to thrive in different environments.
Iguanodon is thought to have been a social dinosaur that could live in herds. This could have been a strategy to protect itself from predators.
Iguanodon fossils have been found in various parts of the world, including Europe and North America, indicating that it had a wide geographic distribution.
