GLOSSARY OF TERMS

Alphadon: (mammal) “First tooth.” A small, omnivorous marsupial, about 1 foot long. Diet: fruit, insects, and small animals. Alphadon was a tree dweller with a prehensile tail. Range: North America, Late Cretaceous.

Apatosaurus: (dinosaur; formerly brontosaurus) “Deceptive lizard.” An herbivore 70 to 90 feet long, 10 to 15 feet high, weighing 30 to 35 tons. Range: North America, late Jurassic.

Ankylosaurus: (dinosaur) “Fused lizard.” An herbivore 25 to 30 feet long, 4 feet tall at the hips, weighing 3 to 4 tons. Range: western United States, Late Cretaceous.

Batholith: A mass of intrusive igneous rock formed deep within the earth’s crust that, due to erosion, has an exposed surface of 100 km² or greater.

Ceratopsia, ceratopsians: (dinosaur) “Horned dinosaur.” Suborder of herbivorous dinosaurs from the Late Cretaceous. They had beaks and bony head frills along the back of the skull.

Champosaur: (reptile) A fish eater living from the Late Cretaceous into the Cenozoic. About 5 feet long, living in rivers and swamps. Range: North America and Europe.

Coleoptera: “Sheathed wing.” Coleoptera, or beetles, make up half the known animal species on Earth. Because their outer pair of wings is a relatively hard structure, beetles fossilize better than do any other insect.

Cretaceous: The last period of the Mesozoic Era, lasting from 144 to 65 million years ago.

Deinosuchus: (reptile) “Terrible crocodile.” Up to 50 feet long, and the largest crocodilian known. Range: North America epicontinental sea, Late Cretaceous.

Dromaeosaur, dromaeosaurus: (dinosaur) “Fast running lizard.” A carnivore about 6 feet long. Range: Alberta, Canada; Montana. Late Cretaceous. A fast-moving predator with large eyes and a sickle-like claw on each foot. Dromaeosauridae were probably the most intelligent of dinosaurs. They include the Velociraptor.

Edmontosaur: (dinosaur) “Edmonton lizard.” Hadrosaur. An herbivore, 42 feet long and 10 feet tall at the hips. Range: western North America, Late Cretaceous.

Hadrosaur: (dinosaur) “Bulky lizard.” Duck-billed herbivores, and the most common dinosaurs. 10 to 40 feet long. Range: North America, Europe, and Asia, Late Cretaceous. Hadrosaurs are divided into crested and noncrested types.

Hell Creek Formation: Upper (late) Cretaceous deposition in North America, to the west of the western Interior Seaway. Named for Hell Creek near Jordan, Montana; the formation occurs in regions of present-day Montana, North and South Dakota, and Wyoming.

Ichthyornis: (bird) “Fish-bird.” 8-inch long, tern-like bird with toothed jaws. The first known bird with a sternum (keeled breast-bone), such as modern birds have. Range: western North America, Cretaceous.

Maastrichtian: 71 million to 65 million years ago. Named for the city Maastricht in the Netherlands, where many fossils (including the first mosasaurs) were found.

Mosasaur: (reptile) Aquatic reptiles of the Late Cretaceous, very common in the US Inland Sea. Some species reached lengths of 59 feet. The first skeleton was discovered about 1780, in the Netherlands.

Ornithischian: “Bird-hipped” dinosaurs, one of the two dinosaur orders (the other being saurischian). 2- or 4-footed herbivores, including hadrosaurs, stegasaurs, ankylosaurs, and ceratopsians.

Ornithomimus: (dinosaur) “Bird-mimic.” A fast-running omnivorous dinosaur from the end of the Cretaceous; 6 to 8 feet tall.

Pachycephalosaur: (dinosaur) “Thick-headed lizard.” A bipedal, herbivorous dinosaur with a rounded skull, thought to have lived in small herds.

Paleocene: The Epoch spanning from 64 to 54.8 million years ago.

Parasaurolophus: (dinosaur) A hadrosaur, bipedal herbivore, duck-billed with a hollow crest 6 feet long.

 

Protungulatum: (mammal) “Before Ungulate.” In the order condylarths, and forerunner of the ungulates. A rat-sized placental mammal known best from the Paleocene North America, but possibly originating in the Late Cretaceous, overlapping with dinosaurs.

Pteranodon: (reptile) “Winged and Toothless.” A winged reptile weighing about 30 pounds, with a 25-foot wingspan.

Purgatorius: (mammal) The earliest known primate-like animal, a rat-sized placental mammal about which little is known. Incomplete fossils are mainly from the Paleocene, although it is possible the animal evolved during the very Late Cretaceous.

Quaternary: the Period from 1.8 million years ago to the present.

Quetzalcoatlus: (reptile) The largest pterosaur, or flying reptile, with a wingspan up to 39 feet, and a neck 9 feet long. Named for the Aztec feathered god Quetzalcoatl.

Sauropods: (dinosaur) “Lizard-footed.” A suborder of the saurischians, sauropods were quadruped herbivores and included the titanisaurids, the largest of all land animals.

Saurischian: (dinosaur) “Lizard-hipped.” Despite the name it is the saurischians rather than the ornithischians (“bird-hipped”) that evolved into birds. Saurischians were divided into the sauropods and the theropods.

Tertiary: The Period of the Cenozoic Era from 65 to 26 million years ago, between the Cretaceous and Quaternary Periods.

Theropod: (dinosaur) “Beast-footed.” A suborder of the saurischians, theropods were fast, bipedal carnivores. They generally had long back legs, short forelegs for grasping prey, excellent stereoscopic vision, and long tails for balancing. It is this group that likely evolved into birds.

Titanosaur, titanosauridae: (dinosaur) The largest of the sauropods.

Triceratops horridus: (dinosaur) “Horrible three-horned face.” A Late Cretaceous herbivore about 30 feet long and weighing 6 to 12 tons, probably living in large herds. A slow mover with a bony frill and large horns, Triceratops may have been similar to the modern rhinoceros, charging at its enemies rather than fleeing. Triceratops is noted for having one of the largest skulls of any animal; at 10 feet long, the skull was almost a third as long as the body.

Troodon: (dinosaur) “Wounding tooth.” A Late Cretaceous, human-sized, bipedal carnivore (theropod), weighing about 100 pounds. Troodon was probably a fast runner, with excellent vision and hearing, and may have been among the most intelligent of dinosaurs. It was named for its distinctly serrated teeth.

Tyrannosaurus rex: (dinosaur) “Tyrant lizard king.” One of the largest of the theropods, T. rex lived between 85 million and 65 million years ago. Fossils have been found in western North America and Mongolia.

Velociraptor: (dinosaur) “Speedy-thief.” Theropod (carnivorous); one of the dromaeosaurids, found in Mongolia. Had a sickle-shaped, retractable claw on each foot.