Iguanodon ‭(‬Iguana tooth‭)

Short Info

Iguanodon ‭(‬Iguana tooth‭)

Phonetic : Ig-wah-no-don.

Named By : Gideon Mantell‭ ‬-‭ ‬1825

Diet : Herbivore

Size : Estimated up to 10 meters long

Type of Dinosaur : Euornithopod

Type Species : I.‭ ‬bernissartensis‭ (‬neotype‭) I. galvensis

Found in : Initially associated with Western Europe,‭ ‬attributed remains are now known in Africa,‭ ‬Asia and North America

When it Lived : Early Cretaceous, 140-110 million years ago

Iguanodon, /I’gwa.n@dan/ i–GWAH-n@–don; meaning iguanatooth’, was named in 1825. It is a genus containing iguanodontian dinosaurs. Although many species have been grouped in the genus Iguanodon and date back to the late Jurassic Period, the early Cretaceous Period in Asia, Europe and North America, taxonomic review in the early 21st Century has determined that Iguanodon is based on I. Bernissartensis. This species lived between the late Barremian and the earliest Aptian Ages (Early Cretaceous), in Belgium, England, Spain and possibly other parts of 126 to 122 million years ago. Iguanodon was a large and bulky herbivore. The distinctive features of Iguanodon include thumb spikes that were large and bulky, possibly to defend against predators. They also have long, prehensile fifth finger, which can be used to forage for food.


Iguanodon de Bernissart IRSNB 01Ben2, CC BY-SA 3.0, via Wikimedia Commons


Gideon Mantell, an English geologist, named the genus in 1825. However, William Harding Bensted discovered the species and gave it the name I. anglicus. Iguanodon, the second type dinosaur to be named after Megalosaurus, was the first. It was used together with Megalosaurus (and Hylaeosaurus) to create Dinosauria. Along with the duck-billed hadrosaurs, the genus Iguanodon is part of the larger Iguanodontia group. As new species are discovered or long-standing ones are reclassified to other genera, the taxonomy of this group continues to be an interesting topic. Louis Dollo, who studied the remains of Iguanodon in Belgium, discovered new and more complete Iguanodons in 1878. These new species were named I. bernissartensis. It was discovered that the remains of Iguanodon in England belonged not to the same species as each other. They were then split into Mantellisaurus and Barilium. It was also discovered that I. anglicus, the type Iguanodon species, was not valid. The name “Iguanodon”, which was derived primarily from Belgian specimens, was thus fixed. Based on fossils from the Iberian Peninsula, I. galvensis was named in 2015.

As fossils have provided new information, scientific understanding of Iguanodon has improved. Researchers have been able to draw inferences about many aspects of Iguanodon’s life, including its movement and feeding habits, thanks to the numerous specimens in this genus. Iguanodon is one of the most well-known and scientifically proven dinosaurs. Its artistic representation has changed significantly as a result of new interpretations of its remains.

Iguanodon was a large herbivore that could switch from bipedality and quadrupedality. I. Bernissartensis is the only species that has been well documented. It weighed in at 3.08 tonnes (3.4 tons) and was approximately 10 meters (33 feet) in length as an adult. Some specimens could have reached 13 metres (43 feet). These animals had tall, narrow skulls with keratin-covered beaks and had teeth similar to iguanas but larger and more tightly packed.

I. Bernissartensis’ arms were quite long, up to 75% of their length. They were also strong and flexible. The hands of I. Bernissartensis had been designed so that the central fingers could support weight. The thumbs were made of conical spikes, which protruded from the main digits. The spike was attached to the animal’s nose in early restorations. The true function of the thumb spikes was revealed by fossils later. They could have been used to defend or foraging for food. The little finger was long and flexible and could have been used for manipulating objects. The phalangeal formula for the innermost finger (phalangeal formula) is 2-3-3-4-2. This means that the next has three bones and the next two. Each foot had three toes and the legs were strong but not designed for running. Ossified tendon, which are tendons that have become bone in their lives, supported the tail and backbone. These rod-like bones are often omitted from drawings and skeletal mounts.

Iguanodon’s teeth look like an iguana’s, but are larger. Iguanodon had only one replacement tooth per position, unlike hadrosaurids who had columns of replacement teeth. The upper jaw could hold 29 teeth, while the lower jaw had 25. These numbers are different because the lower jaw has a wider range of teeth than the upper. The deep inset tooth rows extend from the outside of both the jaws and other anatomical details. It is believed that Iguanodon used a cheek-like structure (muscular or non-muscular) to keep food in his mouth.

Source: Wikipedia