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Glossary I

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Thought to have been one of the earliest of its kind, this small carnivorous bird lived in the Early Cretaceous period. Although it had feathers and a breast bone like modern birds it still had the teeth and claws of its reptilian ancestors

Icarosaurus siefkeri was an early gliding reptile (a lepidosaur) that lived during the Triassic period, roughly 175 to 200 million years ago. It was 7 inches long and had a 10 inch wingspan. [Coelurosauravus is another gliding reptiles that lived 250 million years ago, long before Icarosaurus.] A single fossil of Icarosaurus was found in Granton Quarry, North Bergen, New Jersey, USA 1960 by Alfred Siefker and Michael Bandrowski. Icarosaurus was described by Edwin Harris Colbert in 1961.

An ice age is a time lasting thousands of years during which the Earth is very cold and largely covered by ice and glaciers.

(pronounced IK-nites) Also known as trace fossils or ichnofossils, these are fossilized footprints, nests, dung, gastroliths, burrows, stomach contents, etc., but not actual body parts. Ichnofossils record the movement and behavior of animals. Ichnology is the study of ichnites.

Also known as trace fossils or ichnites, these are fossilized footprints, nests, dung, gastroliths, burrows, stomach contents, coprolite, etc., but not actual body parts. Ichnofossils record the movement and behavior of animals. Ichnology is the study of ichnofossils.

Ichnogenera (meaning: "footprint groups") are groups of dinosaurs whose characteristics are surmised only from their fossilized footprints. When dinosaur trackways are found, it is nearly impossible to determine which dinosaur genus made the prints, so the prints are given a new genus name, an ichnogenus. Some ichnogenera include

1. Theropods (bipeds with relatively long, narrow toes ending in claws): Eubrontes (early Jurassic), Grallator and Coelurosaurichnus (late Triassic), Carmelopodus (middle Jurassic), Anchisauripus (late Triassic to early Jurassic period), and Megalosauripus (late Jurassic).
2. Prosauropods:Tetrasauropus (late Triassic), Pseudotetrasauropus (late Triassic), Otozoum.
3. Sauropods (quadrupeds with 5-toed, elephant-like feet; the inner three or four toes had claws): Brontopodus.
4. Ornithopods (bipeds or quadrupeds with wider tracks and hoof-like claws): Anomoepus, Amblydactylus (a hadrosaur).

Ichnology is the study of fossilized footprints and other ichnofossils.

(pronounced ik-thee-ORN-is) Ichthyornis (meaning: "fish bird") was an 8 inch (20 cm) long, tern-like, extinct bird that lived during the late Cretaceous Period (135-70 million years ago). It had a large head, toothed jaws, and long beak. This powerful flyer is the oldest-known bird that had a keeled breastbone (sternum) similar to that of modern birds. It lived in flocks, nested on shorelines, and hunted for fish over the seas. Ichthyornis was originally found in 1872 in Kansas, USA, by a member of paleontologist Othniel C. Marsh's Yale University expedition. Ichthyornis was named by Marsh in 1872. Fossils have been found in Kansas and Texas, USA and Alberta, Canada. (Subclass Odontornithes, Order Ichthyornithiformes)

A group of marine fish-shaped carnivorous reptiles. They had flippers that were derived from a reptilian forelimb, and whale-like flukes on its tail. Ophthalmosaurus was an ichthyosaur.

Ichthyostega were terrestrial tetrapods (having four-legs) that lived during the late Devonian period. These are the first tetrapods known to have ventrured onto land. These vertebrates were up to about 4 ft (1.5 m) long; they had a wide body, a fish-like skull, four strong, short legs, a massive ribcage, and a finned tail. Adults had no gills. Fossils have been found in East Greenland. Ichthyostega were between fish and amphibians.

When molten rock cools, igneous rock is formed.

This large four legged herbivore lived in the Early Cretaceous period and formed large migratory herds. Iguanodon was a successful species which seems to have evolved teeth for chewing, and a vicious thumb spike with which to catch predators unawares.

(pronounced ig-WAHN-oh-DON-tids) Iguanodontids (family Iguanodontidae, also called Iguanodonts) were large, plant-eating, ornithischian ornithopods who lived from the late Jurassic to the late Cretaceous periods. These dinosaurs had a thumb spike, a toothless beak, a long snout, long toes, and a bulky tail. Altirhinus, Iguanodon, Camptosaurus, Ouranosaurus, Probactrosaurus, Tenontosaurus (perhaps a hypsilophodontid), and Valdosaurus were iguanodontids.The Iguanodontids led to the Hadrosaurids (duckbills).

(pronounced ILL-ee-um) The ilium (plural ilia) is a bone that is part of the hip, or pelvic girdle.

Impact craters are the remains of collisions between an asteroid, comet, or meteorite and the Earth. Some large impact craters include the Chicxulub crater (off the Yucatan peninsula) and the Shiva crater (off the coast of India), both of which date from the K-T boundary, 65 million years ago, and were probably implicated in the K-T mass extinction.

An incertae sedis is a taxonomic name that is uncertain.

Incisor teeth
The cutting teeth that lie at the very front of the jaws of mammals and mammal-like animals.