A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Appendix

Iguanodon

Taxon: Ornithopoda Iguanodontidae

Name means: “Iguana tooth”

Pronounced: I-GWAN-uh-don

Length: up to 33 ft (10 m)

Time: Early Cretaceous, 135 – 110 mya

Place: Europe, Asia, North Africa, South Dakota, Utah

One of the most famous dinosaurs and a more primitive relative of the duckbilled hadrosaurs, Iguanodon was allegedly first discovered by Mary Ann Mantell, the wife of doctor and amateur geologist Gideon Mantell. Though the story holds that Mrs. Mantell was sifting through gravel on a driveway when she found the tooth quite by accident, the less legendary truth is that Dr. Mantell had the gravel delivered to his house from the Tilgate Forest quarries expressly so that he could search for prehistoric teeth and bones. Scientists of the day believed the teeth to belong to mammals or fish when they were first discovered in 1822. By the time Mantell named Iguanodon in 1825, however, he was sure that the mysterious animal in question was a giant plant-eating reptile. When better fossil material was found, Sir Richard Owen reconstructed Iguanodon as a giant, sprawling, lizard-like creature with a horn upon its nose. Later discoveries would show that this horn was actually a thumb-spike, probably used in scraping up plants to eat or for defense against predators and rivals.

Iliosuchus Doubtful name. A small meat-eater, possibly an early tyrannosaurid. It has been suggested that this may be Stokesosaurus.

Taxon: probably Theropoda

name means: “crocodile pelvis”

Pronounced: EE-lee-oh-SOOK-us

size: Small

time: Middle Jurassic

place: England

This small meat-eater is known only from an upper hip bone or ilium. Iliosuchus was discovered in Stonesfield, England and named by von Huene. It has been suggested as an early tyrannosaurid, possibly the same animal as Stokesosaurus. The exact nature of this dinosaur will remain unknown until better, more complete skeletons are discovered.

Indosaurus

Taxon: Theropoda, probably Abelisauridae

Name means: “Indian lizard”

Pronounced: IN-duh-SAW-rus

Length: Large

Time: Late Cretaceous, 70 – 65 mya

Place: India

Imagine paleontologist Charles Matley’s surprise when he unearthed the braincase alone of a heavily-built meat-eater in the bone beds of central India. The massive skull segment suggested that the dinosaur, named Indosaurus in 1933, was big and sturdy, possibly carrying horns above its eyes. Argentine researchers have found many similarities between Indosaurus and abelisaurids like Carnotaurus and Abelisaurus, suggesting that there may once have been a land bridge connecting India and South America, or that the dinosaurs’ common ancestors were widespread on one super continent before the land masses split apart.

Indosuchus

Taxon: Theropoda, probably Abelisauridae

Name means: “Indian crocodile”

Pronounced: IN-do-SOOK-us

Length: 20 ft (6 m)

Time: Late Cretaceous, 70 – 65 mya

Place: India

This large meat-eater was discovered together with Indosaurus. The two may have been

related species.

Ingenia

Taxon: Oviraptoridae

Name means: “for Ingeni”

Pronounced: ing-GAY-nee-a

Length: 6 ft (2 m)

Time: Late Cretaceous, 80 – 70 mya

Place: Mongolia

Ingenia was similar to Oviraptor, but had stubbier, more powerful hands which were tipped with shortened claws. This small biped was probably named for the Ingeni-Khobur depression area in southern Mongolia.

Irritator

Taxon: Theropoda, possibly Tetanurae

Name means: “irritator”

Pronounced: IHR-ih-TAY-tor

Size: about 23 – 26 ft (7 - 8 m)

Time: Early Cretaceous, 112 – 99 mya

Place: Brazil

Possibly a fish-eater, perhaps a spinosaurid or maniraptor, Irritator bore an unusual crest at the rear of its head. The fossil was originally found by commercial fossil collectors who artificially elongated the nose in the hopes of making it appear more complete and valuable. Reconstructing the dinosaur’s original features proved quite frustrating for researchers, and thus it was named Irritator in 1996 by Martill, Cruickshank, Frey, Small and Clark. As reconstructed, Irritator was a theropod with an unusual crest which was probably used as a display structure in competition or attracting a mate. The species name of Irritator challengeri is in honor of the fictional Professor Challenger from Arthur Conan Doyle’s famous novel, The Lost World.

Itermirus

taxon: Theropoda

name means: “of Iternir” (a site in Uzbekistan)

pronounced: EYE-ti-MYE-rus

size: about 5 ft (1.5 m)

time: Late Cretaceous, c. 90 mya

place: Mongolia

This little-known meat eater was described based on the discovery of a braincase with large, unusually well-preserved inner ear cannals. Based on this find, scientists have been able to speculate on the dinosaurian use of those structures for balance and equilibrium. The ear canals show us what the normal posture of the head may have been, as they can be compared to the positioning of similar structures in modern animals. Itemirus may have had exceptional vision. Its braincase is somewhat similar to those of small theropods like Dromaeosaurus. Without more bones to study, little else can be said for certain about this carnivore.