Facts About Iguanodon

01
of 11

How Much Do You Know About Iguanodon?

iguanodon
Jura Park

With the sole exception of Megalosaurus, Iguanodon has occupied a place in the record books for a longer period of time than any other dinosaur. On the following slides, you'll discover fascinating Iguanodon facts.

02
of 11

Iguanodon Was Discovered in the Early 19th Century

iguanodon
Wikimedia Commons

In 1822 (and possibly a couple of years earlier; contemporary accounts differ), the British naturalist Gideon Mantell stumbled across some fossilized teeth near the town of Sussex, on the southeast coast of England. After a few missteps (at first, he thought he was dealing with a prehistoric crocodile), Mantell identified these fossils as belonging to a giant, extinct, plant-eating reptile—which he later named Iguanodon, Greek for "iguana tooth."

03
of 11

Iguanodon Was Misunderstood for Decades After its Discovery

iguanodon
An early depiction of Iguanodon (Wikimedia Commons).

Nineteenth-century European naturalists were slow to come to grips with Iguanodon. This three-ton dinosaur was initially misidentified as a fish, a rhinoceros, and a carnivorous reptile; its prominent thumb spike (see below) was mistakenly reconstructed on the end of its nose, one of the seminal blunders in the annals of paleontology; and its correct posture and "body type" (technically, that of an ornithopod dinosaur) weren't fully sorted out until fifty years after its discovery.

04
of 11

Only a Handful of Iguanodon Species Remain Valid

iguanodon
Wikimedia Commons

Because it was discovered so early, Iguanodon quickly became what paleontologists call a "wastebasket taxon:" any dinosaur that remotely resembled it was assigned as a separate species. At one point, naturalists had named no less than two dozen Iguanodon species, most of which have since been downgraded (only I. bernissartensis and I. ottingeri remain valid). Two "promoted" Iguanodon species, Mantellisaurus and Gideonmantellia, honor Gideon Mantell (see slide above).

05
of 11

Iguanodon Was One of the First Dinosaurs to Be Displayed to the Public

iguanodon
The Crystal Palace Iguanodons (Wikimedia Commons).

Along with Megalosaurus and the obscure Hylaeosaurus, Iguanodon was one of three dinosaurs to be displayed to the British public at the relocated Crystal Palace exhibition hall in 1854 (other extinct behemoths on offer included the marine reptiles Ichthyosaurus and Mosasaurus). These weren't reconstructions based on accurate skeletal casts, as in modern museums, but full-scale, vividly painted, and somewhat cartoonish models. 

06
of 11

Iguanodon Was a Type of Dinosaur Known as an "Ornithopod"

atlascopcosaurus
Atlascopcosaurus, a typical ornithopod (Jura Park).

They weren't nearly as big as the biggest sauropods and tyrannosaurs, but ornithopods—relatively petite, plant-eating dinosaurs of the Jurassic and Cretaceous periods—have had a disproportionate impact on paleontology. In fact, more ornithopods have been named after famous paleontologists than any other type of dinosaur; examples include the Iguanodon-like Dollodon, after Louis Dollo, Othnielia, after Othniel C. Marsh, and the two ornithopods mentioned above that honor Gideon Mantell.

07
of 11

Iguanodon Was Ancestral to Duck-Billed Dinosaurs

corythosaurus
Corythosaurus, a typical hadrosaur (Safari Toys).

It's difficult for people to get a good visual impression of ornithopods, which were a relatively diverse and hard-to-describe dinosaur family that (at least on the smaller end of the size scale) vaguely resembled meat-eating theropods. But it's easier to recognize the immediate descendants of the ornithopods, the hadrosaurs, or "duck-billed" dinosaurs; these much bigger herbivores, like Lambeosaurus and Parasaurolophus, were often distinguished by their ornate crests and prominent beaks.

08
of 11

No One Knows Why Iguanodon Evolved its Thumb Spikes

iguanodon
Wikimedia Commons

Along with its three-ton bulk and ungainly posture, the most notable feature of the middle Cretaceous Iguanodon was its oversized thumb spikes. Some paleontologists speculate that these spikes were used to deter predators, others say they were a tool for breaking down thick vegetation, while still others argue that they were a sexually selected characteristic (that is, males with bigger thumb spikes were more attractive to females during mating season).

09
of 11

Iguanodon Was Only Distantly Related to Modern Iguanas

iguana
A modern iguana (Wikimedia Commons).

Like many dinosaurs, Iguanodon was named on the basis of extremely limited fossil remains. Because the teeth he unearthed vaguely resembled those of modern-day iguanas, Gideon Mantell bestowed the name Iguanodon ("Iguana tooth") on his discovery. Naturally, this inspired some overly enthusiastic but less-than-educated 19th-century illustrators to immortalize Iguanodon, inaccurately, as looking like a giant iguana! (By the way, a newly discovered ornithopod species has been named Iguanacolossus.)

10
of 11

Iguanodons Probably Lived in Herds

iguanodon
BBC

As a general rule, herbivorous animals (whether dinosaurs or mammals) like to congregate in herds, to help deter predators, while meat-eaters tend to be more solitary creatures. For this reason, it's likely that Iguanodon foraged the plains of North America and western Europe in at least small groups, though it's troubling that mass Iguanodon fossil deposits have so far yielded few specimens of hatchlings or juveniles (which may be taken as evidence against herding behavior).

11
of 11

Iguanodon Occasionally Ran on its Two Hind Legs

iguanodon
Wikimedia Commons

Like most ornithopods, Iguanodon was an occasional biped: this dinosaur spent most of its time grazing peacefully on all fours but was capable of running on its two hind legs (at least for short distances) when it was being pursued by large theropods. (By the way, North American populations of Iguanodon may have been preyed upon by the contemporary Utahraptor.)

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Strauss, Bob. "Facts About Iguanodon." ThoughtCo, Apr. 24, 2017, thoughtco.com/things-to-know-iguanodon-1093789. Strauss, Bob. (2017, April 24). Facts About Iguanodon. Retrieved from https://www.thoughtco.com/things-to-know-iguanodon-1093789 Strauss, Bob. "Facts About Iguanodon." ThoughtCo. https://www.thoughtco.com/things-to-know-iguanodon-1093789 (accessed September 20, 2017).