Produced under conditions involving intense heat, as rocks of volcanic origin or rocks crystallized from molten magma.
Describing a species which is abundant and widespread in fossil form, but confined to a specific period of geologic time, such that its presence can be used to geologically date the rocks in which it is found.
Feeding on insects.
The protein that makes up nails, hair, hooves, and horns and other such vertebrate structures.
Small, shrimp-like crustaceans, which form an important food source for filter-feeding marine mammals.
Referring to the female form of an ammonite, in which the female of the species had a larger shell than the male, or microconch.
Naturally occurring molten rock that forms in the Earth's crust; when it erupts it is known as lava.
Extinct family of early carnivores living in North America that gave rise to the dogs, bears, cats, hyenas, etc.
Referring to the male form of an ammonite, in which the male of the species had a smaller shell than the female, or macroconch.
Very old refuse heaps that contain discarded materials, food remains, bones, etc.
Soft-bodied invertebrates including clams, snails, octopi, and squid.
Extinct group of carnivorous marine reptiles.
Abbreviation for million years ago.
Refers to the group of toothless, baleen whales, including gray whales, right whales and rorquals.
A group of marine mollusks which possess an external shell, the most
well known example being the modern chambered nautilus. Also includes
many fossil forms.
The role or functional position of a species within the community of an ecosystem.
Armored herbivorous dinosaur that lacks a clubbed tail, has leaf-shaped teeth and walks on all fours.
Refers to the toothed whales, such as belugas, narwhals, dolphins, sperm and killer whales
Referring to the habit of consuming a broad variety of plant and animal foods
Diverse group of extinct North American hoofed mammals distantly related to modern camels and pigs.
Meaning bird-hipped, it is one of two main groups of Dinosauria and refers to the structure of the pelvis or hip-bone. Ornithischian dinosaurs had pelvises with the pubic bone pointing backward and down from the hip sockets.
See also Saurischian.
Small bones such as those embedded as armor in the skin
A bony plate or scale found in the dermal layers of the skin.
Very diverse group of small crustaceans, mostly only a few millimeters long, occurring in salt and fresh water. Enclosed by a bivalve carapace, they include thousands of living as well as extinct species.
Crescent-shaped lake formed when a meander from a stream is cut off to form a lake.
A group of carnivorous, mostly marine mammals including seals, sea lions, and walruses, with fin-like limbs.
Aquatic organisms, floating and suspended in open water, with little or no locomotion, that drift with the current.
Referring to walking so that the flat sole of the foot comes in contact with the ground; for example, as in modern bears and humans
The theory that the Earth's crust is structured of large, rigid plates that move independently of one another, which can cause deformation at the plate margins.
Member of a formerly very successful order of mammals comprising the living elephants and their extinct relatives.
Any of an order of extinct, alternately branched plants from the Paleozoic Era. This order includes the earliest known terrestrial plants with a vascular structure.
Extinct bird-like, flying reptiles with hollow bones and long beaks that had a flight membrane stretched between the body and an elongated 4th finger.
A method of dating that uses the measurement of decay in naturally occurring isotopes that decay at a constant rate.
The remnants of a once widespread species, which typically are now found in very restricted or isolated areas.
The beak, projection, or extension of the snout of an animal.
Meaning lizard-hipped, it is one of two main groups of Dinosauria and refers to the structure of the pelvis or hip-bone. Saurischian dinosaurs had pelvises with the pubic bone pointing forward and down from the hip sockets.
See also Ornithischian.
Bony plates under the skin
The existence of two visibly different forms for the male and female of the same species.
A rock composed of hardened silt, a fine sedimentary material.
Marine, herbivorous mammals that forage near the surface, such as manatees.
Large dinosaur with a small skull that walked on all fours displaying a double row of alternating upright bony plates and spines down the center of the back.
Any member of a major order, Therapsida. Therapsids were four-legged terrestrial reptiles of the Permian and Triassic Periods. Some were vegetarian; others, carnivorous. They ranged in size from that of a small rodent to a large modern hippopotamus. Most therapsids had died out by the end of the Triassic Period.
Carnivorous dinosaurs that had short fore-limbs and ran or walked on their back legs
Any markings left in sediment by an organism, such as skin prints, foot tracks, borings, burrows, etc. Also called ichnite or ichnofossil.
Fossil footprints that reveal a pattern of movement along a particular area.
Large-headed carnivorous dinosaurs with short, two-fingered hands, that most likely functioned as top predators in the Late Cretaceous ecosystem.
Mammals having hoofs, such as pigs, horses, etc.
Describing an object or organ that has partially or totally lost its original function, such as the appendix in humans.
Large sensitive hairs found on the upper lip of some mammals that aid in tactile sensing.
Text: Margaret Dykens and Lynett Gillette
Illustrations (ammonite, lambeosaurus and albertosaurus): Tim Gunther
Illustration (mosasaur): William Stout