Smithsonian Institution Dinosaur Museum/DINOSAUR_MUSEUM.ISO/pc/mswin/archives/diction.i-q

Text File | 1994-08-06 | 23KB | 689 lines

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."