Smithsonian Institution Dinosaur Museum/DINOSAUR_MUSEUM.ISO/pc/mswin/archives/diction.a-h

Text File | 1994-08-06 | 66KB | 2,094 lines

ACETABULUM:  The cup-shaped socket in
the pelvis which receives the head of the
thigh bone, or femur.  Hip socket.

ALBERTOSAURUS:  [al-BERT-oh-Soar-
uss]  "Reptile from Alberta."  Late
Cretaceous, bipedal, flesh-eating
dinosaur found in North America.
[Montana; New Mexico; Wyoming;
Alberta, Canada].  Slightly smaller than
Tyrannosaurus at up to 26 feet in length.

ALKALOIDS:  Any of a group of organic
compounds that contain nitrogen,
especially those derived from plants.
They have a powerful physiological
effect on animals, and include nicotine,
morphine, codeine, quinine, and
strychnine, among others.

ALLOSAURUS:  [Al-oh-SOAR-uss]
"Strange Reptile."  Late Jurassic,
bipedal, flesh-eating dinosaur found in
western North America.  [Colorado;
Montana; New Mexico; Oklahoma; South
Dakota; Utah; and Wyoming]  The
largest flesh eater of the Jurassic,
growing up to 39 feet long.

AMPHIBIAN:  A vertebrate animal that
hatches from eggs in water, spends its
legless juvenile existence there, then
usually metamorphoses into air-
breathing, land-dwelling, four-legged
adults.

AMPHIBIOUS:  Animal able to live both
on land and in water.

ANATOTITAN:  [ann-Att-oh-TIE-tann]
"Titanic Duck."  Late Cretaceous,
bipedal, herbivorous dinosaur found in
western North America.  [Wyoming].
Closely related to Edmontosaurus.  Up to
33 feet long.  Named by Smithsonian
Museum Specialist Dr. M. K. Brett-
Surman.

ANCESTRAL:  Of, pertaining to, or
inherited from an earlier and usually
simpler type.

ANGIOSPERMS:  True flowering plants
with "seeds in a container."  The
gamete-bearing generation is hidden
within the flower, where the immature
seeds develop within a protective
structure called an ovary.  All other
seed plants are gymnosperms.

ANTRODEMUS:  An old name for
Allosaurus.

ANKYLOSAURS:  Quadrupedal, armored,
ornithischian dinosaurs.

ANKYLOSAURUS:  [ann-Kye-low-SOAR-
uss]  "Fused Reptile."  Late Cretaceous,
quadrupedal, herbivorous, armored
dinosaur found in western North
America.  [Montana; Wyoming; Alberta,
Canada].  Closely related to
Euoplocephalus.

ANTORBITAL FENESTRA:  A hole in the
skull located between the nostril (naris)
and the eye (orbit).

APATOSAURUS:  [ah-Pat-oh-SOAR-uss]
"Deceptive Reptile."  Late Jurassic,
quadrupedal, herbivorous sauropod
dinosaur found in western North
America.  [Colorado; Oklahoma; Utah;
and Wyoming]  Closely related to
Diplodocus.  Up to 69 feet long.  Once
known as "Brontosaurus."

ARCHAEOPTERYX:  [are-kee-OPP-tair-
icks]  "Ancient Wing."  The earliest-
known bird from the Late Jurassic Period
of western Europe [Germany].  Closely
related to dinosaurs.  Roughly the size of
a raven - up to 20 inches long.

ARCHOSAURS:  "Ruling Reptiles."  A
major group of reptiles which includes
not only extinct creatures like
pterosaurs; dinosaurs and their living
relatives, the BIRDS; but also living
examples with a long fossil record, such
as crocodiles and their extinct relatives.

ARMORED:  Possessing bodies that are
covered with bony plates, or that have
projections of bony plates or spikes, or
any combination among the three.

ARTHROPHYTES:  "Jointed Plants."
Plants with jointed stems that reproduce
by spores.  Spore sacs of arthrophytes
are attached to the ends of lateral
branches arranged in whorls on the main
stem.  The earliest-known arthrophytes
are from the Devonian Period.  The sole
modern survivor of this group is
Equisetum.  Sphenopsid is another name
for arthrophyte.

ARTHROPODS:  Any of numerous
invertebrate animals which have jointed
legs, an exoskeleton, and segmented
body parts.  This Phylum includes living
examples such as insects, crustaceans,
arachnids, myriapods, and
onychophorans, and extinct forms like
trilobites.

ARTICULATED:  United by means of
joints.

ASTRAGALUS:  (Azz-TRAGG-ah-luss)  In
vertebrates, the proximal bone of the
foot.  Anklebone.
BAROSAURUS:  [Barr-oh-SOAR-uss]
"Heavy Reptile."  Late Jurassic,
quadrupedal, herbivorous, sauropod
dinosaur found in western North America
[South Dakota; Utah; and Wyoming] and
Tanzania.  Closely related to Diplodocus.
Up to 89 feet long.

BIOSPHERE:  That portion of Planet Earth
occupied by living things.

BIPED:  An animal that walks on its two
hind feet.

BIPEDAL:  Describes an animal that is a
biped.

BRACHIOSAURUS:  [Brack-ee-oh-SOAR-
uss]  "Arm Reptile."  Late Jurassic,
quadrupedal, herbivorous, sauropod
dinosaur found in western North
America, [Colorado; Utah] Tanzania,
Algeria, and Portugal.  Up to about 75
feet long.  Possibly the heaviest dinosaur
ever.

BRACHYCERATOPS:  [Brack-ee-SAIR-
ah-tops]  "Short-horned Face."  Late
Cretaceous, quadrupedal, herbivorous,
juvenile ceratopian dinosaur found in
western North America [Montana].
Closely related to Pachyrhinosaurus.  Up
to 13 feet long.

BRAINCASE:  Bones of the skull which
contain the brain as well as guard it.

BRONTOSAURUS:  See Apatosaurus.

BROWSERS:  Animals which feed on the
tender twigs, shoots, and leaves of
trees and shrubs.
CAMARASAURUS:  [kamm-Air-oh-
SOAR-uss]  "Chambered Reptile."  Late
Jurassic, quadrupedal, herbivorous,
sauropod dinosaur found in western
North America [Colorado; Montana; New
Mexico; Utah; and Wyoming] and
Portugal.  Up to 59 feet long.  Best-
preserved skeletons of all-known North
American dinosaurs.

CAMBRIAN:  Cambrian Period:  A
geologic time unit.  The oldest period
of the Paleozoic Era, from about 545
million to 510 million years ago.  The
first appearance of shelled
invertebrates, such as brachiopods,
trilobites, molluscs, and echinoderms.
Pikaea, the first-known chordate, had
appeared by the Middle Cambrian; and
Anatolepis, thought by some to be a
vertebrate, is found in rocks of the
Late Cambrian.  All life was in the sea,
none was on land yet.

CAMPTOSAURUS:  [Kamp-toe-SOAR-
uss]  "Bent Reptile."  Late Jurassic,
bipedal/quadrupedal, herbivorous,
iguanodontoid dinosaur found in western
North America [Colorado; Oklahoma;
South Dakota Utah; Wyoming] and
England.  Up to 23 feet long.

CANNIBAL:  Any animal which feeds on
others of its own kind.

CANNIBALISM:  The act of animals
devouring others of their own species.

CANNIBALIZE:  To practice cannibalism.

CANOPY:  The cover or crown of all
vegetation high overhead, formed by
leaves, needles, and branches.

CARBONIFEROUS:  Carboniferous Period:
A geologic time unit.  A period of the
Paleozoic Era between about 363 million
and 290 million years ago.  Its name was
chosen to reflect its vast coal deposits,
which had long been mined for fuel.  Also
known as the "Coal Age."  In North
America, the Carboniferous is divided
into the Mississippian and Pennsylvanian
periods.  Their mutual boundary is about
323 million years ago.

CARCASS:  The dead body of an animal.

CARNAGE:  Extensive and bloody
slaughter of animals; massacre.

CARNIVORE:  A mammal which eats
mostly flesh.

CATASTROPHE:  A great and sudden
disaster.

CAUDAL:  Pertaining to the tail region.

CENOZOIC: Cenozoic Era:  A geologic
time unit, which began about 65 million
years ago and continues to the present.
During the Cenozoic Era plants and
animals began to look much like those
of today.  Birds, insects, mammals, and
flowering plants became the dominant
forms of life.  It is in this era that
humans first appear.  Don't be mislead,
though.  Dinosaurs and prehistoric man
did not live at the same time.  The first
sign of early man, Homo habilis, was
not until about 2 million years ago.
More than 63 million years had passed
since the extinction of the dinosaurs.

CENTROSAURUS:  [Senn-troe-SOAR-uss]
"Sharp-point Reptile."  Late Cretaceous,
quadrupedal, herbivorous, ceratopsian
dinosaur found in Alberta, Canada.  Up to
20 feet long.

CERATOPSIA:  This clade of dinosaurs
includes the "horned" dinosaurs, and it is
the last group of dinosaurs to appear.
The Ceratopsia is comprised of the
psittacosaurs, protoceratopsids, and the
ceratopsids.

CERATOPIANS:  Same as ceratopsians.

CERATOSAURUS:  [sair-ATT-oh-Soar-
uss]  "Horned Reptile."  Late Jurassic,
bipedal, flesh-eating, theropod dinosaur
found in western North America
[Colorado; Utah].  Up to 19 feet long.
One of the few theropods with a nose
horn.  Teeth like knife blades.

CERVICALS:  The vertebrae (backbones)
of the neck.

CHAMBERED:  A structure having hollow
areas inside.

CHASMOSAURUS:  [KAZZ-moe-Soar-
uss]  "Cleft Reptile."  Late Cretaceous,
quadrupedal, herbivorous, medium-sized
ceratopsian dinosaur found in western
North America [Texas; Alberta,
Canada].  Up to 17 feet long.  Distant
relative of Triceratops.

CHEVRONS:  Bony projections on the
caudal vertebrae that extend down and
back, and provide attachment sites for
the tail muscles.  Synonym for hemal
arches.

CLADE:  A group of organisms whose
members are more closely related
among themselves than they are to other
groups.  Theoretically, a group of
genetically related organisms.

CLADOGRAM:  A diagram showing the
relationships among clades.  A cladogram
is constructed on the basis of derived
characteristics, rather than primitive
characteristics.  For example, land-
dwelling vertebrate animals
(amphibians, reptiles, birds, and
mammals) possess both bone and paired
limbs for locomotion on land.  Such
characteristics are considered to be
primitive because they are shared by all
land-dwelling vertebrates, and are
therefore of little use in establishing
relationships.  Derived characteristics,
on the other hand, are specializations
that evolved after the primitive
characteristics became established.  For
example, the amniote egg is a primitive
characteristic because it is shared by
reptiles, birds, and mammals.  Hair and
mammary glands are derived
characteristics because they serve to
differentiate the mammals from the
birds and reptiles.  Also, live birth is
derived, and indicates that monotremes
(egg-laying mammals) differ from the
marsupials (pouched mammals) and
placental mammals.

CLASS:  A taxonomic category in
Linnaean biological classification.  A
subdivision of a Phylum, comprised of a
group of related Orders.  For example,
Class Reptilia is in Phylum Chordata, and
includes the 5 living orders of reptiles,
and 35+ orders of extinct ones.

CLASSIFICATION: (BIOLOGICAL)  The
process of placing individual organisms
into a distinct group sharing
characteristics in common, which is
distinguished from other such groups.
All the individuals of a group are
believed to be related to each other
through descent from a common
ancestor.  The categories, from highest
to lowest, are kingdom, phylum, class,
order, family, genus, and species.

CLAVICLE:  Collar bone.  Found in
saurischian dinosaurs, mammal-like
reptiles, birds, and most mammals,
except for modern marine forms.

CLUB MOSSES:  A lycopsid.  The most
ancient lycopsid of several groups known
from the fossil record.  Club mosses are
still with us today; they are "living
fossils."  Living club mosses are species
of Lycopodium, a variety of tiny plants,
erect or creeping, in which the leaves
are arranged in a spiral pattern around
the stem.  Lycopodium is common in
many parts of the United States, and
frequently is used in Christmas
decorations, and for that reason is often
called "running pine" or "ground pine."
Lycopodium reproduces by spores which
are released from a structure that is
somewhat club shaped, hence the name,
"club moss."  Club mosses are neither
mosses nor pines, which are bryophytes
and seed plants, respectively.  Another
kind of lycopsid is Isoetes, the quillwort.

CLUTCH:  The number of eggs produced
at one laying, all together in a group.

COELOPHYSIS:  [Seal-oh FIE-siss]
"Hollow Form."  Late Triassic, bipedal,
flesh-eating theropod dinosaur found in
western North America [Arizona; New
Mexico].  Up to 10 feet long.

COELUROSAURIA:  A taxonomic grouping
that includes Deinonychosaurs,
Dromaeosaurs, Ornithomimosaurs,
Tyrannosaurs, and BIRDS.

"COLD-BLOODED:"  An outdated term
once used to describe an animal with an
internal body temperature that is
relatively lower than in living mammals,
and that changes in response to the
temperature of the animal's
environment.

COMPSOGNATHUS:  [Komp-soe-NAY-
thuss]  "Pretty Jaw."  Late Jurassic,
bipedal, flesh-eating theropod dinosaur
found in France and Germany.  Up to 2
feet long.  Smallest-known adult
dinosaur.

CONIFERS:  Seed plants (gymnosperms)
that are shrubs and trees having
needlelike or scalelike leaves, and seeds
borne in cones.  Examples are cedars,
hemlocks, firs, larches, pines, spruces,
and yews.

CONTINENTAL DRIFT:  The lateral
movement of the continents with respect
to one another across the face of the
earth.

COPROLITES:  Fossilized dung (manure).

CORYTHOSAURUS:  [koe-Rith-oh-SOAR-
uss]  "Corinthian Helmet Reptile."  Late
Cretaceous bipedal/quadrupedal,
herbivorous, duck-billed dinosaur found
in western North America [Montana;
Alberta, Canada].  Up to 33 feet long.
Possessed a head crest that was helmet-
shaped.

CRETACEOUS:  Cretaceous Period: A
geologic time unit.  The third and final
period of the Mesozoic Era.  It lasted
from about 146 million to 65 million
years ago.  This is when dinosaurs
achieved their maximum diversity, and
the ornithischians were dominant.  The
end of the Cretaceous is defined by the
mass extinction of all dinosaurs, as
well as the pterosaurs, and all the
marine reptiles except for turtles and
crocodiles.

CYCADEOIDS:  Extinct group of seed
plants (gymnosperms) that look like
modern cycads, and for that reason are
called cycadeoids.  Modern cycads
produce pollen and seeds on separate
plants, and have cones.  In most
cycadeoids, however, each plant
produced both pollen and seeds, and the
cones had an almost flowerlike structure
- but never opened.  Trunks of fossil
cycadeoids were generally thick and
marked by diamond-shaped leaf scars
arranged in spirals.  The geologic range
is from the Triassic through Cretaceous
periods.

CYCADS:  Cycads are seed plants
(gymnosperms) with woody stems.
They have foliage resembling that of
palms, but their reproductive organs are
cones that resemble those of conifers.
Pollen and seed are produced on separate
plants in cones that are massive.  There
are only a few survivors of the cycad
line, which originated in the Permian
Period.  Although more abundant in the
geologic past than they are today,
cycads were never dominant.  Modern
cycads are confined to tropical and
subtropical regions, and even there they
occur in scanty patches in out-of-the-
way places.  They are a diverse group,
but small in numbers.  However, the
individual plants grow so luxuriantly
that they are popular decorative plants
on lawns and patios.  There are nine
genera, four of which belong to the
Western Hemisphere, and five to the
Eastern.  The great cycad regions of the
world are Mexico and the West Indies in
the Western Hemisphere, and Australia
and South Africa in the Southern
Hemisphere.
DECAY:  To rot and/or disintegrate.

DECIDUOUS:  A term applied to plants
that lose their leaves every year.

DEINONYCHUS:  [die-NONN-ee-kuss]
"Terrible Claw."  Lower Cretaceous,
bipedal, flesh-eating theropod dinosaur
found in western North America
[Montana; Wyoming].  Up to 10 feet long.
Possessed recurved, knife-blade teeth,
razor-sharp claws on both hands and
feet, and a sickle claw on each foot.

DENTARY:  The primary tooth-bearing
bone of the lower jaw.  (See maxilla.)

DEVONIAN:  Devonian Period:  A unit of
geologic time.  A period within the
Paleozoic Era which occurred from
about 409 million to 363 million
years ago.  Known as the "Age of Fish"
because there were no vertebrates on
earth other than fishes until the very
end of the Devonian Period.

DIGESTION:  The process by which food
is decomposed into simple substances
which can be assimilated more easily.

DILOPHOSAURUS:  [die-Loaf-oh-SOAR-
uss]  "Two-ridged Reptile."  Early
Jurassic, bipedal, flesh-eating theropod
dinosaur found in western North
America. [Arizona; Washington]  Up to
19 feet long.  Possessed two long,
narrow bony ridges on the skull.

DIGITIGRADE:  Walking so that only the
toes touch the ground.  Common
examples include dogs, cats, and
horses.

DIMORPHISM:  Refers to having two
different sizes and/or shapes of
individuals in the same species.  The
term is most often used in reference to
sexual dimorphism, in which the male
and female are noticeably different in
appearance.

DINOSAUR:  A special type of extinct
land-living reptile with an erect gait.  A
member of an archosaur group that lived
between about 225 million and 65 million
years ago.  Dinosaurs can be classified
into two clades:  SAURISCHIA and
ORNITHISCHIA.  The word, DINOSAURIA,
as translated in 1842 by its originator,
Sir Richard Owen, literally means
"FEARFULLY-GREAT LIZARD."
Therefore, dinosaurs technically are not
"terrible reptiles," as they are often
called in the vernacular.  Also, they are
neither terrible nor are they lizards!

DIPLODOCUS:  [dih-PLODD-oh-kuss]
"Double Beam."  Late Jurassic,
quadrupedal, herbivorous, sauropod
dinosaur found in western North
America.  [Colorado; Utah; Wyoming]
Closely related to Apatosaurus.  Up to
89 feet long.  One of the longest
dinosaurs known.

DISEMBOWEL:  To remove the entrails
(slang - guts) from an animal.

DNA:  (deoxyribonucleic acid)  The
chromosome-bearing material of a living
cell in all organisms except certain
viruses.

DORSAL:  "Back."  The upper side of an
animal.  Opposite of ventral.

DORSAL VERTEBRAE:  Term given to
certain back bones of the spinal column
in some land animals.  Generally thought
of as the vertebrae between the
cervicals and the sacrum.

DRYOSAURUS:  [Dry-oh-SOAR-uss]
"Oak Reptile."  Late Jurassic ornithopod
dinosaur.  Bipedal herbivorous dinosaur
found in western North America and
Tanzania.  [Colorado; Utah; Wyoming;
Tanzania]  Up to 13 feet long.

DUCK-BILLED DINOSAURS:  A common
name for the large, wide-beaked
ornithopods which are known as
hadrosaurs.  All the members of the
families Hadrosauridae  and
Lambeosauridae.
ECOLOGY:  The study of the relationships
between organisms and their
environment.

ECTOTHERMIC:  See ectothermy.

ECTOTHERMY:   "Outside Heat."  The
physiological condition in which an
animal's body heat is controlled by the
external environment.  It says nothing
about whether the body temperature is
constant or fluctuates, relatively high or
low.  This term does not mean "cold-
blooded."

EDMONTOSAURUS:  [ed-MONN-toe-Soar-
uss]  "Reptile from Edmonton."  Late
Cretaceous, duck-billed, ornithopod
dinosaur.  Possessed the following
traits:  quadrupedal; herbivorous; no
crest or nasal expansion; and wide-
snouted.  Found in western North
America.  [Alberta and Saskatchewan,
Canada; Colorado; Montana; North
Dakota; South Dakota; Wyoming]

EMBRYO:  A plant or animal in the
earliest stages of development;
generally still contained within the seed,
egg, or uterus.

ENDOTHERMIC:  See endothermy.

ENDOTHERMY:  "Inside heat."  The
physiological condition in which an
animal's body heat is controlled
internally and maintained at a constant
level.  It says nothing about whether the
body temperature is relatively high or
low, or whether the animal's metabolic
rate at rest is high or low.  This term
does not mean "warm-blooded."

EORAPTOR:  [Ee-oh-RAPP-toar]  "Dawn
Thief."  Late Triassic bipedal flesh-
eating dinosaur discovered in 1992 by
Paul Sereno in the badlands of Argentina.
A very early theropod the size of a
sheep.  Eoraptor is thought to be very
close to the common ancestor of all
dinosaurs.

EPOCCIPITALS:  The small bones along
the outside rim of ceratopsian frills that
serve to reinforce the edge.  The frill of
Triceratops displays good examples of
epoccipitals.

EROSION:  The process of disintegrating
or decomposing exposed rocks
(weathering), transporting the debris,
and depositing it somewhere else.

EUORNITHOPODS:  "True Bird Feet."  A
subdivision of clade Ornithopoda that
includes the hypsilophodontids and the
iguanodontoids.  Includes all the
ornithopods of the Late Jurassic and
Cretaceous periods.

EURAMERICA:  The land area of eastern
North America and western Europe,
which were joined together during much
of the Mesozoic Era.

EVOLUTION: (ORGANIC)  Organic
evolution is often defined as the change
in the genetic makeup of a population
with time.  It can also mean the change in
species composition of a biological
community over time.  The phrase, "the
theory of evolution," itself is
misleading.  Organic evolution (as change
over time) is a FACT.  It is the theory
about the mode or mechanism of organic
evolution which has everyone debating.

EXTINCT:  No longer living anywhere.
See extinction.

EXTINCTION:  The death of a species so
that it no longer exists anywhere.
FAMILY:  A taxonomic category in
Linnaean biological classification.  A
subdivision of an Order, consisting of a
grouping of similar genera.

FAUNA:  Animals, or animal life.

FIBULA:  The outer of the two bones
forming the lower part of the leg.  It lies
outside the shin bone.

FEMUR:  The thigh bone.

FENESTRA:  "Window."  An opening
through bone.  For example, one of the
"windows" or holes in the jaw, and in
the skull around the eye-hole.  Besides
lightening the skull, certain holes there
were the sites where new and powerful
jaw muscles originated.  Bony struts and
braces between the fenestrae strengthen
the skull.

FLORA:  Plants, or plant life.

FOLIAGE:  Plant leaves.

FORELIMBS:  An animal's front legs,
arms, or wings.

FOSSIL:  Any evidence of life from the
geologic past.  For example, buried bones
may be infiltrated by ground water
carrying dissolved minerals that fill up
the spaces where the blood vessels lay
and cells of marrow used to live.  Such
fossil bone is therefore partly composed
of real bone and partly of other minerals
that have replaced some of the original
organic tissue.

FOSSILIZATION:  All processes involving
the burial of a plant or animal, and in the
preservation of all, part, or a trace of
it.

FOSSIL RECORD:  The history of life on
earth as revealed in fossil remains.

FROND:  In plants, a large, usually
compound leaf, as in ferns and palms.
Term sometimes used for leaflike organs
in seaweed.

FUNCTIONAL MORPHOLOGY:  Inferring
function from the study of a fossil's
morphology, that is, its form and
structure.

FUSED:  Joined or welded together.  It is
common for dinosaurs to have some
fused vertebrae, especially in the region
of the pelvis.
GAIT:  The type of movement on land by
terrestrial vertebrates, such as
walking, trotting, or running.

GALLIMIMUS:  [Gal-ih-MEEM-uss]
"Chicken Mimic."  Late Cretaceous,
ornithopod dinosaur which possessed the
following traits:  bipedal; bird-like beak;
claws; and long hind legs.  Found in
Mongolian People's Republic.

GASTRALIA:  "Belly Ribs"  Dermal ribs
that lie in the abdominal region and
attach to the dorsal ribs.  They are found
in many reptiles, both fossil and living.
Good examples among the dinosaurs
include Allosaurus and Tyrannosaurus.

GASTROLITHS:  "Stomach Stones."
These are stones swallowed by some
living reptiles and birds to aid in the
digestion of tough plant material.  The
gastroliths act as mill balls to break up
the plant matter.  Associated with some
sauropod dinosaurs.

GENUS:  A taxonomic category in
Linnaean biological classification.  A
subdivision of a Family, consisting of a
grouping of similar species.  For
example. the genus Tyrannosaurus
consists of the species Tyrannosaurus
rex from America, and Tyrannosaurus
bataar from Asia.

GEOLOGIC TIME:  The term applied to the
time extending from the end of the
formative period of the Earth as a
separate planetary body, to the
beginning of written or human history,
or from about 4.6 billion years ago to
10,000 years ago.  From largest to
smallest, the categories of geologic time
units are:  eon, era, period, epoch, and
age.

GEOLOGY:  The study of planet Earth.
The various subdivisions or
specializations include:  Geomorphology,
Glaciology, Oceanography, Hydrology,
Invertebrate Paleontology, Vertebrate
Paleontology, Paleobotany,
Sedimentology, Stratigraphy, Structural
Geology, Mineralogy, Petrology,
Volcanology, Geochemistry, Geophysics,
Seismology, Tectonics, Ore Geology,
Petroleum Geology, and Engineering
Geology.

GEOLOGIST:  A scientist who studies the
Earth.  See Geology.

GINKGO:  "GHEEN-koe."  A woody
deciduous seed plant (gymnosperm) with
distinctive fan-shaped leaves, also
known as the "maidenhair tree."  The
naked seeds are borne on elongated
stalks.  Native to China, but cultivated in
the United States.  Extremely resistant
to urban pollution.  It is the last in a line
of trees, once widely distributed, that
dates back to the Permian Period,
possibly earlier.  It is a "living fossil."

GIRTH:  The distance around a circular
or cylindrical object.  Its circumference.

GIZZARD:  A section of the thick,
muscular stomach wall of birds in
which the food is ground up.  The first
stomach of insects, provided with
horny plates for macerating or sifting
food.  Thought to have occurred in
some dinosaurs, based on the
association of gastroliths with
some sauropod skeletons.

GONDWANA:  "Land of the Gonds."  The
hypothetical supercontinent composed
of the present-day continents of Africa,
Australia, India,  Antarctica, and South
America.  It began to form in the
Precambian, was fully assembled in
the Permo-Carboniferous, and its
breakup started in the Triassic Period,
when Pangaea began to split between
North America and Africa.  Gondwana
was named by Eduard Suess, an Austrian
geologist, and based on the occurrence
of the Glossopteris flora in India,
Madagascar (Malagasy Republic),
Australia, South Africa, and South
America.  After the turn of the century,
Glossopteris was also found in
Antarctica.

GORGOSAURUS:  See Albertosaurus.

GRAZERS:  Animals that feed on grass.
No dinosaurs were grazers.

GYMNOSPERMS:  Plants with exposed
seeds (not enclosed in a protective
covering).  Any seed plant lacking true
flowers.
HADROSAURINE:  Non-crested
hadrosaurid.

HADROSAURS:  The duck-billed
dinosaurs.  They are composed of two
groups, the hadrosaurines or flat-headed
duckbills, and the lambeosaurines or
crested duckbills.  The hadrosaurs were
one of the only groups of dinosaurs to
shred food like mammals in the zone of
occlusion where the teeth came together
in a large grinding motion.

HADROSAURUS:  [Had-roe-SOAR-uss]
"Sturdy Reptile."  Late Cretaceous,
duck-billed, ornithopod dinosaur.
Possessed the following traits:
bipedal/quadrupedal; herbivorous; and
"Roman-nosed."  The first dinosaur in
North America to be scientifically
described.  Up to 32 feet long.  Found in
New Jersey.

HAPLOCANTHOSAURUS:  [Hap-low-
Kanth-oh-SOAR-uss]  "Single-spined
Reptile."  Late Jurassic sauropod.
Herbivorous, quadrupedal dinosaur
reaching a length of up to 72 feet.  Found
in western North America.  [Colorado;
Wyoming]

HERBIVORE:  An organism that consumes
living plants or their parts.

HERRERASAURUS:  [hair-REHR-rah-
Soar-uss]  "Herrera's Reptile."  One of
the earliest-known dinosaurs.  A
bipedal, late Triassic, flesh-eating
theropod. Up to ten feet in length.  Found
in Argentina.

HETERODONTOSAURUS:  [Hett-err-oh-
Don-toe-SOAR-uss]  "Different-toothed
Reptile."  Early Jurassic, ornithopod
dinosaur.  Bipedal herbivore not quite 4
feet long.  The jaws had three types of
teeth:  small, sharp, cutting teeth; short
curved tusks (perhaps in males only);
and close-packed shearing teeth that
acted side to side as well as up and
down.  Found in South Africa.

HIERARCHY:  A body of persons or
things, which are grouped in successive
or inclusive categories, according to
their rank.
HINDLIMBS:  The back or rear legs of an
animal.

HIND LIMBS:  The back or rear legs of an
animal.

HORSETAILS:  Living arthrophytes.  The
sole survivors of a once common group
of plants are members of the one living
genus, Equisetum, and are commonly
called horsetails or scouring rushes.
Horsetails and scouring rushes are
sphenopsids, a group of jointed-stem
plants that were most abundant during
the Carboniferous Period.  In ancient
coal swamps, members of this group
such as  Calamites, a relative of
Equisetum, grew to heights of over 50
feet.  Although the rest of the
sphenopsids were extinct by the early
Mesozoic Era, Equisetum has existed
almost unchanged since the
Carboniferous Period.  It is still widely
distributed, living in moist habitats,
much as its ancestors did.  Equisetum is
a spore-bearing plant with true roots,
stems, and leaves.  The stems are
hollow and are jointed.  Whorls of leaves
occur at each joint.  These leaves
usually are long and narrow, and
sometimes are very reduced.  Most
plants are small, less than 3 feet high.
Some species of Equisetum are
sometimes called scouring rush because
they contain small grains of abrasive
silica, and early settlers in North
America used the plant to scrub their
pots and pans.  A "living fossil."

HOT-BLOODED:  An outdated term for an
animal that uses its metabolism to
maintain a relatively high and constant
body temperature, usually higher than
that of the environment.

HUAYANGOSAURUS:  [hoy-Yang-oh-
SOAR-uss]  "Reptile from Huayang."
Middle Jurassic, plated dinosaur.  A
primitive stegosaur with dorsal plates,
many spines, and pre-maxillary teeth.
Quadrupedal herbivore which grew up to
15 feet in length.

HUMERUS:  The upper arm bone.  Not to
be confused with humorous (funny).
ICHNOLOGY:  The study of trace fossils,
including tracks and other traces of
animal activity.

ICHTHYOSAURS:  "Fish-Reptiles."
Marine reptiles of the Mesozoic Era.
They were not dinosaurs, but rather
dolphin-shaped and very specialized
swimming reptiles.

IGUANODON:  [igg-WANN-oh-donn]
"Iguana Tooth."  Early Cretaceous
ornithopod dinosaur.  Large,
bipedal/quadrupedal herbivorous
dinosaur with a broad toothless beak,
cheek teeth, hoof-like claws, and a
thumb spike.  The teeth were ridged and
tightly packed like those of modern
iguana lizards.  Shares with
Megalosaurus the honor of being one of
the two dinosaurs to first receive a
scientific name.  Up to 33 feet long.
Found in Belgium, England, Germany,
Spain, and possibly in South Dakota.

ILIUM:  This bone is one of a pair of the
three sets of bones that form the pelvis.
The ilia are topmost, and form a
connection with the backbone.  The ilium
also helps to form the hip socket
(acetabulum), into which fits the head of
the thighbone (femur). Plural is ilia.

INFRAORDER:  A taxonomic category in
Linnaean biological classification.  A
subdivision of a Suborder consisting of a
grouping of similar Families.

ISCHIUM:  "Hip"  This bone is one of a
pair of the three sets of bones that form
the pelvis.  It is on the bottom toward
the rear.  It also forms part of the
acetabulum, or hip joint, and provides an
attachment area for muscles that
operate the hind limb.  Plural is ischia.
JURASSIC:  Jurassic Period:  A geologic
time unit.  The second period in the
Mesozoic Era.  It  lasted from about 208
million to 146 million years ago, when
dinosaurs achieved their maximum size,
and the saurischians were dominant.

JUVENILE:  Young, not fully developed.
Not yet adult.
KENTROSAURUS:  [Ken-troe-SOAR-uss]
"Prickly Reptile."  Late Jurassic
dinosaur bearing plates and spikes.
Related to Stegosaurus.  Quadrupedal
herbivore which grew up to about 17
feet in length.  Found in Tanzania.

KINEMATICS:  The study of how things
move in relation to one another in the
abstract, and without considering the
effect of mass and forces.  For example,
the study of how both jaws move with
relation to the braincase.
LAMBEOSAURINE:  The hadrosaurids
with hollow crests on the skull.

LAMBEOSAURUS:  [Lamm-bee-oh-SOAR-
uss]  "Lambe's Reptile."  Large crested
dinosaur of the Late Cretaceous.
Bipedal/quadrupedal, herbivorous
dinosaur with a dominant head crest that
is shaped like a hatchet.  Close relative
of Corythosaurus.  This dinosaur grew
up to 33 feet in length.  Found in western
North America.  [Alberta, Canada; Baja
California, Mexico]

LATITUDE:  Distance north or south of
the equator, generally expressed in
degrees along an arc of a circle, as on a
map or a globe.

LAURASIA:  "Laurentia and Eurasia."
The northern hypothetical
supercontinent composed of the present-
day continents of Asia, North America,
and Europe.  It began to form in the
Precambrian, was fully assembled in the
Permo-Carboniferous, and started to
break up in the Late Triassic Period
when North America split from Africa.
Throughout the Triassic, Laurasia north
of the Maritime Provinces remained
intact.  By the Jurassic the mid-Atlantic
rift began to extend itself northward,
and counterclockwise rotation of the
Iberian peninsula pinched off the western
end of the Tethys Sea.  By the Late
Cretaceous, Greenland began to separate
from Europe at the same time
northeasternmost North America was
still attached to Greenland and northern
Europe.  Early in the Cenozoic Era the
North Atlantic rift slowly penetrated
northward until eventually the North
American and European continents were
completely separated.

LESOTHOSAURUS:  [leh-Soo-too-SOAR-
uss]  "Reptile from Lesotho."  Early
Jurassic bipedal herbivore with a small
head, strong legs, and long tail.  It grew
up to 3 feet 4 inches long.  Found in
Lesotho, Africa.

LIZARD:  Any of numerous reptiles of
the Suborder Sauria having an elongate
scaly body, four legs, and a long,
tapering tail.

LYCOPSIDS:  Leafy, spore-bearing
plants, with closely spaced simple
leaves.  Spore sacs are borne on the
upper surfaces of the leaves, or at the
point where the leaves are attached to
the stem.  The earliest-known lycopsids
are from either the Silurian or Devonian
of Australia.  Devonian lycopsids gave
rise to those of today, making this the
oldest lineage of plants.
MAGNETIC FIELD:  A region
characterized by a detectable magnetic
force at every point.

MAIASAURA:  [My-ah-SOAR-ah]  "Good
Mother Reptile."  Late Cretaceous
hadrosaur.  Bipedal/quadrupedal,
herbivorous dinosaur with a small head
crest and a short beak.  A famous
discovery of a Maiasaura nesting colony
in 1978 revealed for the first time the
parental nurturing that was practiced by
adult Maiasaura.  Found in Montana.

MAMMAL.  Any one of a number of
vertebrate animals of Class Mammalia,
consisting of some 15,000 species,
including man.  Mammals are
distinguished by having hair, specialized
teeth, separate air and food passages, a
complex brain, and a constant, self-
regulated, warm body temperature.
Females have milk glands and give birth
to living young.

MANDIBLE:  The lower jaw.

MANIRAPTORA:  A clade which includes
most of the Cretaceous theropods plus
the Dromaeosaurs and their
descendants, the BIRDS.  This group is
defined by having some wrist bones
which are curved and allow greater
range of motion in the wrist.  The
Maniraptora is the largest subdivision of
the Coelurosaurs.

MARGINOCEPHALIA:  A taxon which
includes the Ceratopsia (horned
dinosaurs) and the Pachycephalosauria
(dome-headed dinosaurs).   This group is
defined by the bones at the back of the
skull growing outward to form a shelf,
ornamented ridge, or shield, which
overhangs the neck in most forms.

MAXILLA:  The primary tooth-bearing
bone of the upper jaw.  (See dentary.)

MEGALOSAURUS:  [Megg-al-oh-SOAR-
uss]  "Big Reptile."  Middle Jurassic
theropod dinosaur.  Large, bipedal flesh
eater.  Discovered in England and named
in 1824.  The scientific naming of
dinosaurs started with Megalosaurus.

MESOZOIC: Mesozoic Era:  A unit of
geologic time.  The middle era of life,
also known as the "Age of Reptiles."  It
is subdivided into three periods - from
earliest to latest:  Triassic, Jurassic,
and Cretaceous.

MIGRATE:  To move periodically from
one region or climate to another.

MISSISSIPPIAN:  Mississippian Period:
A unit of geologic time in the Paleozoic
Era which occurred about 363 million
to 323 million years ago.  Sea level,
which had  lowered near the end of the
Devonian Period, rose during the
Mississippian so that warm, shallow
seas flooded the continents at low
latitudes in broad sheets.  As a result,
limestones accumulated over large
areas, often with crinoid debris as
their main component.  For this reason,
the Mississippian is known as the "Age
of Crinoids."  A term used only in North
America for the early Carboniferous
Period, and based upon the excellent
exposures of limestones of this age
along the Mississippi River Valley.

"MONOCLONIUS:"  [Mon-oh-CLON-ee-
uss]  "Single Horn."  Late Cretaceous
ceratopsian dinosaur which possessed a
massive head and large nose horn.
Herbivorous, quadrupedal dinosaur, up
to 20 feet long.  Now considered to be
Centrosaurus.  Found in western North
America.  [Montana; Alberta, Canada]

MOSASAURS:  A group of extinct marine
reptiles that appeared late in the
Cretaceous Period, and became extinct
at the close of the Cretaceous, along
with the dinosaurs and pterosaurs.
Mosasaurs were extremely large
swimming lizards, related to modern-
day monitor lizards.  Mosasaurs
marauded shallow marine waters, and
probably were the most formidable
marine predators of their time.  They
ate smaller mosasaurs, sea turtles,
squid, and ammonites, all active
swimmers themselves.  Mosasaurs
swam like eels, undulating their long
slender bodies from side to side.  Their
feet were modified into steering
paddles, formed by the bones in their
fingers and toes.
NARIS:  External opening of the nasal
passage.  Plural is nares.

NATURAL SELECTION:  The primary
mechanism of Charles Darwin's Theory
of Evolution.  It is a natural process in
which the environment operates on the
variation within the gene pool of a
population, and selects certain
individuals for survival because of
differences in longevity and rate of
production of viable offspring.

NICHE:  The role of an organism in its
environment as the two interact.
OBSOLETE:  Gone out of use, discarded,
worn out.  In biology, body parts or
organs that have atrophied or are
imperfectly developed.

OCCIPITAL CONDYLE:  (ox-SIPP-it-Tall
CONN-dial)  An enlarged, rounded
prominence at the back of the head which
articulates with the atlas (the first
vertebra of the neck).

OMNIVORE:  An animal whose diet is
broad, including plant and animal foods,
both.

ORDER:  A taxonomic category in
Linnaean biological classification.  A
subdivision of a Class consisting of a
grouping of similar families or
suborders.  For example, the Order
Saurischia is composed of the suborders
Sauropodomorpha and Theropoda, and all
the families within each.

ORDOVICIAN:  Ordovician Period:  A unit
of geologic time within the Paleozoic
Era which occurred from about 510
million to 439 million years ago.  Sea
level stood high during much of the
Ordovician, flooding broad stretches of
eastern proto-North America.  Warm
shallow seas favored the deposition of
limestone in a setting much like that of
the Bahamas today.  Gondwana lay
squarely on the equator late in the
Cambrian, but by the mid-Ordovician,
only its northern  portion was
equatorial.  Near the close of the
Ordovician glaciers formed in the
southern polar regions of Gondwana, and
as the period ended glaciation reached
its climax, and the cooling of climates
contributed to the major marine
extinction that marks the close of the
period.

ORNAMENT:  Anything that decorates,
adorns, or embellishes.

ORNITHOPOD: (Orr-NITH-oh-pod)  "Bird
Foot."  A descriptive term for any
dinosaur in the Ornithopoda, all of which
are herbivorous.

ORNITHISCHIA:  One of the two clades
that make up the Dinosauria.  The other
is the Saurischia.  The Ornithischia
includes five basic clades:  Ornithopoda
(bipedal herbivores with highly evolved
teeth; Stegosauria (the "roofed" or
plated herbivores); Ankylosauria (the
armored herbivores);
Pachycephalosauria (dome-headed
herbivores); and the Ceratopsia (horned
herbivores).  All Ornithischians have a
pre-dentary bone in the lower jaw.

ORNITHOMIMUS:  [orn-Ith-oh-MEEM-
uss]  "Bird Mimic."  Late Cretaceous
ostrich-mimic dinosaur.  Grew up to 6
and a half feet in length and possessed
extremely large eyes.  Found in western
North America.  [Colorado; Utah;
Alberta, Canada]

ORNITHOPODA:  One of the largest and
most long-lived Ornithischian clades.  It
is the main branch of the bipedal
Ornithischia, consisting of
heterodontosaurids, hypsilophodontids,
dryosaurids, iguanodontids, and
hadrosaurids.

OVIRAPTOR:  [Oh-vee-RAPP-tor]  "Egg
Seizer."  Late Cretaceous, bird-like
predator.  Bipedal flesh eater
possessing two long arms with huge
hands ending in agile, grasping, clawed
fingers.  It had a deep beak with two
tooth-like bones inside.  Oviraptor may
have fed on freshwater clams.  Found in
People's Republic of Mongolia.
PACHYCEPHALOSAURIA:  In the Linnaean
classification system, an Order of
dinosaurs.  These are the "dome-headed"
dinosaurs, and are represented by the
smallest number of specimens among all
the dinosaur orders.  Order
Pachycephalosauria is comprised of the
families Homalocephalidae and
Pachycephalosauridae.

PACHYCEPHALOSAURUS:  [pack-ee-
Seff-ah-low-SOAR-uss]  "Thick-headed
Reptile."  Late Cretaceous, bone-headed
dinosaur.  Bipedal herbivore with a
distinctive, thick, dome-shaped skull.
The thick skull may have been used in
head-butting contests for social
dominance, and to fend off predatory
dinosaurs.  The largest one known is 26
feet in length.  Found in North America.
[Montana; South Dakota; Wyoming]

PALATABLE:  Acceptable or agreeable to
the taste.

PALEOANTHROPOLOGIST:  A person who
studies fossil humans, their artifacts,
and their culture.  (See paleontologist.)

PALEOBIOLOGY:  The study of fossils as
organisms, rather than as static objects
in the rocks.

PALEOECOLOGY:  The study of the
relationships between organisms of the
geologic past and their environments,
based on fossil faunas and floras and
their relative positions in the rocks.

PALEOGEOGRAPHY:  The geography of
the geologic past.  For example, the
historical reconstruction of the earth's
surface, or of the pattern of lands and
seas, or of a given area at a particular
time in the geologic past.

PALEOMAGNETISM:  The permanent
magnetism acquired by a rock at the
time it formed, which can be used to (1)
determine the location of the magnetic
poles and (2) the latitude of the rock at
the time it became magnetized.  Only
iron-rich minerals have this property.
For example, when rocks melt, the iron-
bearing minerals orient themselves in
the earth's magnetic field and are frozen
in that position when the rock solidifies.
Also, iron grains in sediments orient
themselves in a similar manner as they
settle through the water column.  The
study of these magnetic bearings allows
geologists to plot the changing location
of the continents with respect to the
poles through time.

PALEONTOLOGIST:  A person who
studies ancient life, exclusive of
humans.  (See paleoanthropologist.)

PALEONTOLOGY:  The study of life from
the geologic past by using fossils.

PANGAEA:  "All Land."  The one single
hypothetical supercontinent that included
all the modern continental masses,
which came together during the Permo-
Carboniferous, and began to split up
during the Late Triassic Period.  Pangaea
consisted of Laurasia (the northern part)
and Gondwana (the southern portion).

PANTHALASSA:  "All seas."  The great
universal ocean that surrounded Pangaea
prior to its breakup.

PARASAUROLOPHUS:  [Pair-ah-soar-
AWL-oh-fuss]  "Like a Crested Reptile."
Late Cretaceous duckbill with an
extremely long, tubular crest extending
back from the top of the skull.
Bipedal/quadrupedal, herbivorous
dinosaur, up to 33 feet long.  Found in
North America.  [New Mexico; Montana;
Alberta, Canada]

PELVIS:  "Basin"  The hip region of the
skeleton in vertebrate animals.  The
pelvis consists of three sets of paired
bones, fused together into a solid mass.
The bones are the ilium, ischium, and
pubis.  In the plural, they are the ilia,
ischia, and pubes.

PENNSYLVANIAN:  Pennsylvanian Period:
A unit of geologic time.  A period within
the Paleozoic Era which occurred from
about 323 million to about 290 million
years ago.  During this time vast coal
deposits formed in tropical, lowland
swamps where fallen trees accumulated
in large numbers.  Fossils of the earliest-
known reptiles are found in hollow
stumps of large "scale trees," or
lycopsids, from the coal swamps.  A
term used only in North America for the
late Carboniferous Period, and based
upon the widespread occurrence of coal-
bearing rocks of this age in the state of
Pennsylvania.

PENTACERATOPS:  [Pen-tah-SAIR-ah-
tops]  "Five-horned Face."  Late
Cretaceous, quadrupedal, long-frilled
ceratopian dinosaur which grew up to
about 22 feet in length.  The skull of this
dinosaur had two long brow horns and a
nose horn, making a total of three.  The
two cheek "horns" are really pointed
cheek bones which occur in the skulls of
nearly all ceratopians.  Found in western
North America.  [New Mexico]

PERMIAN:  Permian Period:  A unit of
geologic time.  The youngest and last
period of the Paleozoic Era, from about
290 million to 251 million years ago.
The end of the Permian is defined by the
largest mass extinction in the fossil
record, much larger than the extinction
that included the demise of the dinosaurs
about 185 million years later.

PERMO-CARBONIFEROUS:  The Permian
and Pennsylvanian periods combined.
The last two periods of the Paleozoic Era
taken as a unit.

PHALANGES:  Bones of the fingers and
toes.

PHANEROZOIC:  "Obvious, or Visible Life"
A unit of geologic time, an eon.  The
Phanerozoic Eon dates from the first
appearance of animals with hard parts in
the fossil record, about 545 million
years ago, up to today.  It includes three
eras, the Paleozoic, Mesozoic, and
Cenozoic.

PHOTOSYNTHESIS:  The process by
which an organism uses energy from
light to make organic molecules from
inorganic raw material.  An example is
the way green plants make sugar from
carbon dioxide and water by using
chlorophyll and light.

PHYSIOGRAPHY:  A description of the
features and phenomena of nature.

PHYTOSAURS:  Early crocodile-like
archosaurs of the Triassic Period.

PLAGUE:  A pestilence or epidemic
disease of man or animals, usually
highly infectious, intensely malignant,
and fatal.  An example is the bubonic
plague, caused by a bacterium that is
transmitted to man by fleas which had
fed on infected rats.

PLATEOSAURUS:  [Plat-ee-oh-SOAR-
uss]  "Flat Reptile."  Late Triassic
prosauropod dinosaur with a small head,
long neck, and large body.  Bipedal,
herbivorous dinosaur which could also
walk on all fours.  Grew up to 26 feet in
length.  Found in France, Germany, and
Switzerland.

PLEISTOCENE:  The latest "Ice Age,"
which began about 1.6 million years ago,
and is still going on today.  Other ice
ages occurred in the late Precambrian,
the Ordovician Period, and the Permo-
Carboniferous.

PLESIOSAURS:  Large marine reptiles of
the Mesozoic Era, with huge flippers for
swimming, and long necks.  Not a
dinosaur.

POLARITY:  The quality of having two
opposing attributes.  In physics, the
quality by which a body exhibits certain
properties related to a line of direction
through its mass, the properties at one
end of this line being of opposite or
contrasting nature to the properties at
the other end.

PRECAMBRIAN:  A dimensionless unit of
geologic time, from about 4600 million
billion to 545 million years ago.
Precambrian is the term given to
geologic time extending since the
formation of the planet, about 4600
million years ago, up to the first
appearance of complex organisms with
hard parts.  Time prior to the
Precambrian is not represented by
rocks, but that is when the universe
formed, perhaps 13 billion to 20 billion
years ago, followed much later by the
origin of the solar system, including
planet Earth, about 4.6 billion years ago.
The earliest part of the Precambrian is
not represented by rocks either, so
scientists believe that during the early
history of the earth its surface was
molten, with small patches of solid outer
crust being consumed as soon as they
formed.  As the time went by, the
surface temperatures lowered, and
about 3.9 billion years ago a thin outer
crust solidified, characterized by
numerous volcanoes pouring out vast
quantities of lava and gas.  The gases
and water vapor expelled by volcanoes
condensed to form oceans and an
atmosphere conducive to the synthesis
of living things.  The oldest-known fossil
is a stromatolite, about 3500 million
years old, although it's possible that life
originated on Earth well before that.
Stromatolites of today are layered
structures made by microorganisms that
live in shallow water, trap dirt
suspended in the water, and bind it into
layers.  Scientists don't know what
microorganisms made the stromatolites
in the Precambrian, because the
microorganisms are not preserved.
Cyanobaceria and bacteria make the
stromatolites of today.  Perhaps these
were the organisms that built the
stromatolites of the Precambrian, as
well.  The first fossils with hard parts
appeared about 545 million years ago.
This marks the end of the Precambrian,
and the beginning of the Cambrian Period
of the Paleozoic Era.  It also marks the
beginning of the Phanerozoic Eon.

PREDATOR:  Any animal that captures
and eats other animals.

PREDENTARY:  A small crescent-shaped
bone at the tip of the lower jaw, found
only in ornithischian dinosaurs.

PREMAXILLA:  Either of a pair of tooth-
bearing bones of the upper jaw of
vertebrates located in front of the
maxillae.  In most mammals they are
distinct and bear the incisor teeth.

PRONE:  Lying flat, with the face or
front downward, facing the surface it
rests upon.

PROSAUROPOD: (pro-SOAR-ah-pod)  A
group of plant-eating dinosaurs that
lived in the Triassic and Jurassic
periods.  The earliest group of the
Sauropodomorpha to appear.

PROSAUROPODA:  This is the earliest
group of the Sauropodomorpha to
appear, and it is composed of the
Anchisaurs, Blikanasaurs,
Massospondylosaurs, Melanorosaurs,
Plateosaurs, Thecodontosaurs, and
Yunnanosaurs.

PROTOCERATOPS:  [Pro-toe-SAIR-ah-
tops]  "First-horned face"  Late
Cretaceous ceratopian dinosaur with a
bony frill, but neither brow nor ridge
horns.  Quadrupedal herbivore growing
up to 6 feet in length.  This dinosaur is
known from all stages of life, including
eggs.  Found in People's Republic of
China, and Mongolian People's Republic.

PTEROSAURIA:  "Winged Reptiles."  This
is the order of flying reptiles, which is a
group closely related to the dinosaurs
and their ancestors.  Order Pterosauria
is divided into two suborders, the
earlier Rhamphorhynchoidea, and the
later Pterodactyloidea.

PTEROSAURS:  (TAIR-oh-soars)  The
flying reptiles, the last of which became
extinct when the dinosaurs did.  They
lived from the Late Triassic through the
Cretaceous periods.  See Pterosauria.

PUBIS:  "Mature."  One of a pair of the
three sets of bones that make up the
pelvis.  It is the most forward of the
three, and lies under the back part of the
belly.  Many muscles that move the legs
forward originate here.  Plural is pubes.
QUADRUPED:  An animal that walks on
all fours.

QUADRUPEDAL:  Describes an animal
that is a quadruped.

QUATERNARY:  Quaternary Period:  A
unit of geologic time.  It began about
1.6 million years ago, and includes
the Pleistocene and Holocene epochs.
The Quaternary follows the Tertiary
Period, and together they are "The
Age of Mammals."
RADIUS:  One of the two long bones of
the lower arm.  It allows the arm to be
rotated about its long axis by
articulating with the ulna.

RECURVED:  Curved backward or
inward, as in teeth.

REPTILES:  Vertebrate animals with
skins made of scales of horn, and no
free-living larval stage.  They hatch in a
miniature adult stage from eggs laid on
dry land.

RESONATOR:  A device which reinforces
or causes prolongation of sound by
vibrating in concert with the source of
the sound.

RIGOR MORTIS:  The stiffening of the
body muscles following death.

ROSTRAL BONE:  The beak-like bone
found at the tip of the upper jaw, but
only in ceratopSian dinosaurs.
SACRALS:  The vertebrae that fuse the
backbone to the pelvis.  In most
dinosaurs there are five to ten sacrals.
The ilia are the pelvic bones that fuse
with the sacrals.

SACRUM:  (SAY-krumm)  A composite
bone formed by the fusion of vertebrae,
and forming the dorsal part of the
pelvis.

SAURISCHIA:  One of the two clades of
dinosaurs.  It includes the taxa
THEROPODA (the flesh-eaters) and
SAUROPODOMORPHA (the sauropods,
and prosauropods and their relatives).

SAUROPODA:  "Reptile Feet."  This clade
is the group of classic herbivorous
"brontosaurus-like" dinosaurs, and is
formed by the brachiosaurids,
camarasaurids, cetiosaurids,
diplodocids, euhelopodids, shunosaurids,
titanosaurids, and vulcanodontids.

SAUROPODS:  Vernacular for members
of the Sauropoda.

SAVANNA:  A wide open plain of tall
grasses in a tropical region,
interspersed with trees and shrubs.  The
plants are able to survive a hot, dry
season of considerable length.

SCAPULA:  The shoulder blade.

SCLEROTIC RING:  A ring made of flat,
plate-like bones in the eyeball.  Shaped
like a pineapple slice, this ring helps to
maintain the eyeball's shape.

SCUTELLOSAURUS:  [scoo-Tell-oh-
SOAR-uss]  "Small-Bony Plate Reptile."
Early Jurassic, ornithopod dinosaur up
to 53 inches in length.  Quadrupedal
herbivore, which had hundreds of bony
knobs in its skin.  Found in Arizona.

SERRATED:  Having jagged or notched
projections like saw teeth.

SILURIAN:  Silurian Period:  A unit of
geologic time.  A period within the
Paleozoic Era which occurred from about
439 million to 409 million years ago.
After the Ordovician extinction, there
was an evolutionary recovery of many of
the decimated taxa.  The broad, shallow
seas of the Silurian teemed with life.  In
the tropics, a diverse community of
marine organisms built reefs larger than
any than any earlier ones.  More
advanced predators were in the oceans,
including the first jawed fishes.  Land,
which had been devoid of living things
until this time, was conquered by plants,
then animals, in quick succession at the
close of the period.

SPECIES:  A taxonomic category in
Linnaean biological classification.  In
biology, a subdivision of a Genus and
composed of a grouping of organisms of
a population which is capable of
interbreeding and producing viable
offspring, and is reproductively isolated
from other such groups.  The same
word, species, is used for both singular
and plural.

SPHENOPSID:  Another name for
arthrophyte.

STEGOCERAS:  [stegg-AWE-sair-uss]
"Horny Roof."  Late Cretaceous, bone-
headed dinosaur.  Bipedal herbivore,
growing to 6 and a half feet in length.
Relative of Pachycephalosaurus.  Found
in western North America.  [Montana;
Alberta, Canada]

STEGOSAURIA:  This clade is made of
the roofed (sometimes called plated)
dinosaurs, and includes the stegosaurs
and huayangosaurs.  Together with the
ANKYLOSAURS [and SCELIDOSAURS]
they form the clade Thyreophora.

STEGOSAURUS:  [Stegg-oh-SOAR-uss]
"Roofed Reptile."  Plated dinosaur of the
Late Jurassic Period which grew up to
29 feet in length.  This is the only plated
dinosaur known to be in North America.
The 17 plates of bone aligned in two
rows along the back of Stegosaurus
probably were used in regulating body
temperature.  Four prominent spikes
were located at the end of a muscular
tail.  Found in western North America.
[Colorado; Wyoming; Utah]

STRUTHIOMIMUS:  [Strew-th-ee-oh-
MEEM-uss]  "Ostrich Mimic."  Late
Cretaceous, bipedal, theropod dinosaur
which grew up to 13 feet in length.
Found in Alberta, Canada.

STYRACOSAURUS:  [sty-Rack-oh-
SOAR-uss]  "Spiked Reptile."  Late
Cretaceous, short-frilled, ceratopian
dinosaur which grew up to 18 feet in
length.  The back edge of the frill
contained 6 long spikes, and the snout
had a long horn.  Two hollow window-
like openings in the frill, just like those
of Centrosaurus, probably were covered
with flesh in life.  Found in western
North America.  [Montana; Alberta,
Canada]

SUCCULENT:  A plant with thick, fleshy
stems or leaves that conserve moisture.
Juicy.

SUPERNOVA:  A really big star, with a
mass at least eight times that of the
sun, that blows up.  These are rare
celestial events, with only seven super
novae known to have occurred in our
Galaxy during recorded history.  A
super nova explosion throws material
from the star all over the Universe,
resulting in an extremely bright, short-
lived phenomenon that pours out vast
amounts of energy.

SUPERSAURUS:  [SUE-purr-Soar-uss]
"Super Reptile."  Late Jurassic,
sauropod dinosaur which grew to an
incredible length of up to 98 feet.
Quadrupedal, herbivorous dinosaur.
Closest relative of Diplodocus.  Found in
Colorado.

SYMMETRICAL:  Being of equal size and
shape on opposite sides of an axis.
TALONS:  Sharp claws of an animal.

TAPHONOMY:  The study of the burial
history of an organism.

TAXA:  Plural of taxon.

TAXON:  In biological classification, the
name given to a group of related
organisms of any rank, such as the name
given to a species, genus, family, order,
class, phylum, kingdom, or clade.

TAXONOMIC CATEGORY:  In biological
classification, the unit designation of a
group of related organisms of any rank,
such as species, genus, family, order,
class, phylum, kingdom, or clade.

TAXONOMY:  The theory and practice of
describing, classifying, and naming
organisms, living or fossil.

TENDON: A fiber of connective tissue
that forms the end of a muscle and
attaches it to a bone.

TERTIARY:  Tertiary Period:  A unit of
geologic time, which began about 5
million years ago and ended about 1.6
million years ago.  The Tertiary and
Quaternary periods together are the
Cenozoic Era.  During the Tertiary,
grasslands advanced at the expense of
forests, mammals reached their peak of
diversity, and spread to inhabit
virtually all land masses.  The earliest-
known fossils of Homo, our genus, are
found in rocks dating about 2 million
years old.

TETANURAE:  A related group (clade) of
dinosaurs which has two divisions: the
Carnosaurs and Coelurosaurs.  Included
in the Coelurosauria are the
Ornithomimosaurs (ostrich-like
dinosaurs), the Dromaeosaurs (bird-like
dinosaurs), and BIRDS.  Another way of
defining this group is THEROPODA
without the Ceratosauria.  The 4th and
5th fingers are lost.

TETHYS:  A great east-west trending
seaway that lay between Laurasia and
Gondwana during the Paleozoic and
Mesozoic eras.  The final closure of this
circum-equatorial ocean began with the
docking of India against Asia in the
Eocene Epoch, about 50 million years
ago, followed in the Miocene by Africa's
collision with southern Europe.  The Alps
and Himalayas arose from the vise-like
squeezing of Tethys between Laurasia
and Gondwana.

TETRAPOD:  "Four-legged."  A four-
legged or four-limbed vertebrate that
may use all legs for walking
(quadruped), but may also be bipedal.
Included are:  Amphibians, Sauropsids
(Reptiles plus Birds) and Synapsids
("Pelycosaurs" plus Therapsids and
Mammals).

THECODONT:  (THEE-koe-dont)  "Socket
Tooth."  A mixed group of early
archosaurs from the Permian and
Triassic periods that includes ancestors
of dinosaurs, crocodiles, and
pterosaurs.

THEROPOD:  Bipedal, flesh-eating
saurischian dinosaurs.

THYREOPHORA.  This group of dinosaurs
consists of the closely related
Scelidosauridae, Stegosauria, and
Ankylosauria.

TIBIA:  The larger of the two bones of
the hind leg below the knee.  The shin
bone.

TON:  A unit of weight equal to 2,000
pounds (short ton), commonly used in
the United States and Canada.  In Great
Britain, the long ton of 2240 pounds is
used.  A metric ton is 1000 kilograms,
or 2204.6 pounds, and is sometimes
spelled tonne.

TOOTH BATTERY:  A complex unit
formed by interlocking teeth in multiple
rows, as many as 5 or 6.  The best
example is the tooth battery of
hadrosaurs, with over 600 teeth per
battery that are ever-growing, self-
sharpening, and always being replaced
from below.

TORSO:  The trunk of the body.  That
part of the body excluding the head,
pelvis, and limbs.

"TRACHODON:"  [TRACK-oh-donn]
"Rough Tooth."  Late Cretaceous, duck-
billed dinosaur.  An old name no longer in
use.  See Edmontosaurus.

TRIASSIC:  Triassic Period:  A unit of
geologic time, the first period in the
Mesozoic Era.  The Triassic lasted from
about 251 million to 208 million year
ago.  Fossils of both dinosaurs and
mammals first appeared in the Carnian
Stage of the Upper Triassic.

TRICERATOPS:  [try-SAIR-ah-tops]
"Three-horned Face."  Late Cretaceous,
ceratopian dinosaur which grew up to
about 30 feet in length.  A quadrupedal
herbivore, Triceratops was one of the
largest and heaviest of all ceratopians.
Triceratops had two long brow horns, a
short nose horn, and a long frill made of
solid bone.  The last-known dinosaur to
become extinct.  Found in western North
America [Colorado; Montana; South
Dakota; Wyoming; Alberta, Canada; and
Saskatchewan, Canada].

TRIPOD:  Having three feet or legs.
Tripodal is to have a three-legged
stance.

TUOJIANGOSAURUS:  [too-Hwang-oh-
SOAR-uss]  "Reptile from Tuojiang."
Late Jurassic, plated dinosaur
possessing tail spikes and back plates
made of bone, both of which were
smaller than those on Stegosaurus.
Quadrupedal herbivore up to 20 feet in
length.  Found in People's Republic of
China.

TYPE SPECIMEN:  An actual specimen
used to describe a new species, and thus
is part of the basis for defining it.

TYRANNOSAURUS:  [tye-Rann-oh-
SOAR-uss]  "Tyrant Reptile."  The
largest flesh-eating land animal ever
known on Earth.  Late Cretaceous
theropod.  Bipedal, flesh-eating dinosaur
that grew up to 50 feet long.  Its skull
was over five feet in length, with jaws
more than 4 feet long, and teeth up to 8
inches from root to tip.  The front limbs
were extremely small for the size of the
body, about as long as a person's arm,
yet extremely strong.  The arm of
Tyrannosaurus ended in a two-fingered
hand, each finger bearing a stout claw.
Found in western North America
[Colorado; Montana; New Mexico, South
Dakota; Texas; Utah; Wyoming; Alberta,
Canada; and Saskatchewan, Canada],
Peoples's Republic of China, and
Mongolian Peoples's Republic.
UBIQUITOUS:  Being, or seeming to be
everywhere at the same time.

ULNA:  One of the two long bones of the
lower part of the front leg, or arm.  It
articulates with the radius, and is on the
same side of the leg as the fifth digit.
Most of the muscles that pull the arm
forwards and backwards attach to the
ulna.  The upper end of the ulna is the
"elbow."

ULTRASAURUS:  [Ull-trah-SOAR-uss]
"Ultra Reptile."  A name given to two
different dinosaurs that lived in
different places at different times and
may or may not be closely related.  One
is from South Korea and formally
named, the other is from western North
America [Colorado].  The skeletal
material recovered so far suggests they
both are probably Brachiosaurus.

UTAHRAPTOR:  [You-taw-RAPP-torr]
"Utah Predator."  Late Jurassic, large,
bipedal, flesh-eating dinosaur with a
sickle claw on each foot.  Large relative
of Deinonychus.  Known only from
fragments.  Found in North America.
[Utah]
VEGETATION:  The plants of an area or
region.

VELOCIRAPTOR:  [Veh-loss-ih-RAPP-
torr]  "Speedy Predator."  Late
Cretaceous, bipedal, flesh-eating
dinosaur with a sickle claw on each foot.
Relative of Deinonychus which grew up
to 11 feet in length.  Found in People's
Republic of China and Mongolian People's
Republic.

VENTRAL:  "Belly."  The underside of an
animal.  Opposite of dorsal.

VERTEBRA:  One of the segmented bones
of the spinal column, or backbone.  They
begin at the base of the skull, to which
the first vertebra is joined, and then
pass over the hips at the pelvis.
Vertebrae beyond the pelvis are
referred to as caudals, or tailbones.
Plural is vertebrae.
"WARM-BLOODED:"  An outdated term
once used for living birds and mammals,
animals that maintain a nearly uniform
body temperature, generally higher than
their surroundings.

WOOLLY MAMMOTH:  A hairy elephant
with large tusks that lived during the
latest ice age and became extinct
approximately 4,000 years ago.