Glossary A
A priori
Latin for \\\\\\\"from (somthing) previous\\\\\\\" based on what is generally known; said of a conclusion about a specific instance that derives from a knowledge of the relevant general facts or conditions.
Abduction
The movement of a body part away from the midline axis of the body [compare adduction]
Absolute age
The age of an object as established by some precise dating method, such as radiometric dating [compare relative age]
Absolute dating
A means of estimating the age of rocks with some degree of accuracy using measurements of radioactive isotopes
Acceleration
An evolutionary change in which the descendant species has a faster growth rate than the ancestral species.
Accretation
1. In anatomy, a process in which the growth or building up of some structure or mass occurs by the accumulation of fresh layers of material on top of existing layers.
2. A similar process in geology; e.g. the gradual buildup of land on a shoreline by wave action.
Acetabulum / Acetabular / Acetabula
The socket on the hip into which the head of the femur fits. */* Plural, acetabula, a cuplike socket in the bones that form the hips and pelvis, into which the head of the femur fits.
Acidosis
A metabolic disturbance in which the normal acid-base balance of the body is altered and the blood or tissue becomes excessively acidic.
Acrodont / Acrodontia
1. Describing a form of tooth arrangement in which the teeth sit on top of the jawbone and are often fused to it.
2. An animal having this arrangement of teeth. Thus acrodontia [ compare thecocont, pleurodont ]
Acromion
A bony process in the outher end of the scapula ( shoulder blade )
Acronomic
Describes an animal that dwells in high places (treetops, cliffs, etc.)
Adaptation
1. The general ability of a species to undergo evolutionary change in response to its environment.
2. A particular development, behavioral, anatomical, or physiological change in a population of organisms, in response to environmental conditions.
Adduction
The movement of a body part toward the midline axis of the body. [ compare abduction ]
Adductor
Closer (i.e. jaw adductor muscle is a jaw-closing muscle)
Aeolian
Relating to or caused by the action of wind; dispersed by the wind.
Aestivate
To hide away and become inactive during periods of drought
Aëtosaurs
Heavily-armoured, plant-eating archosaurs of the Triassic Period
Affinity
A close relationship or common ancestry of organisms, suggsted by resemblances in their anatomy, behavior, or other features.
Agonistic behaviour
The interaction of members of the same species in various behavioral patterns in response to social conflict; e.g., attack, retreat.
Algae
Aquatic plants.
Allochthonous
Not originating at its present site; formed elsewhere. [ compare autochthonous ] Material that is formed or introduced from somewhere other than the place it is presently found. In impact cratering this may refer to the fragmented rock thrown out of the crater during its formation that either falls back to partly fill the crater or blankets its outer flanks after the impact event.
Allometry / Allometrics
1. The relative growth rates of the different parts of a given organism.
2. The study or measurement of the size or growth rate of organisms. Also allometrics.
Allotype
A term, not regulated by the Code, for a designated specimen of opposite sex to the holotype.
Altricial
Describing a species in which the young are relativly undeveloped when born. [ compare precocial ]
Altricial behaviour
The fact or activity of caring for newly born offspring by their parent or parents. Also, parental behaviour.
Alula plural / Alulae / Alular
1. The portion of a bird\\\\\\\'s wing, that corresponds to the human thumb; this structure is fundamental in modern birds for low-speed flight and maneuverability.
2. A group of small feathers at this side. Thus, alular
Alveoli singular / Alveolus / Alveolar
In anatomy, a cavity, pit or socket; e.g, the numerous tiny air cells in the lungs in which the exchange of oxygen and carbon dioxide takes place, or the bony sockets in the jaw in which the roots of the teeth are held in place. Thus, alveolar
Ammonite
1. A type of ammonoid fossil that has a thick, strongly ornamented shell with complex lines of juncture.
2. See Ammonoid
Ammonoid / Ammonoidae
A widespread, diverse group of mollusks ( Ammonoidae ), noted for their large, distinctive chambered shell. Though now extinct, ammonoids occurred in vast numbers in acient seas within a distinct time span; thus they are important in fossil study because their presence ( or absence ) can be used to date the rocks in which they are found ( or not found ).
Amnion
A fluid-filled sac enveloping the embryo or fetus during development.
Amniote
One of the Amniota, land-dwelling vertebrates having an amnion; amniotes thus include modern reptiles, birds, and mammals.
Amphibious
Living, or capable of living, both on land and in water.
Amphicoelous
Describes vertebrae in which the front and back of the centrum are concave. A feature of dinosaur vertebrae that were not supposed to move very much relative to one another, such as posterior dorsals
Anaerobic
Without oxygen; not requiring or involving the presence of oxygen.
Anagenesis / Anagenetic
An evolutionary change in which modified forms replace one another in continuous succession without branching into new taxa; descent without modification and the formation of new sepcies. Thus, anagenetic.
Anapsid / Anapsida
One of the Anapsida, a group of amniotes including the oldest known forms, distinguished by a skull having a complete covering of dermal bones, with no opening ( fenestra ) in the side of the skull behind the orbit (eye socket); e.g., turtles.
Anchor taxa
Describes the taxa used to define a phylogenetic taxon or clade
Angiosperm / Angiospermae
Any of the Angiospermae, the flowering plants; a plant that bears its seeds in a closed seed vessel.
Angular bone
A mandible bone
Anterior adj.
Forward of; toward the front or skull
Anticline
An upward fold of stratified rock in which the sides slope down and away from the crest; the oldest rocks are in the center, and the youngest ones on the outside.
Antorbital
Relating to or located in the area in front of the orbit; i.e, in front of the eye socket.
Antorbital fenestra
Fenestration in front of the orbit (eye socket) */* A distinctive opening, in the skull in front of the eye socket, characteristic of the archosaurs.
Apatite
A phosphate mineral that is a major constituent of sedimentary phosphate rocks and also of the bones and teeth of vertebrates
Apomorph / Apomorphy / Apomorphic
A character in an organism that is derived from, but that is no longer the same as, an ancesteral character. Thus, apomorphy, apomorphic. [compare plesiomorph]
Aposematism
The fact of having distinctive coloration (or another such feature) that acts as a deterrent or warning to potential predators.
Aquatic
Living in the water.
Arboreal
Living exclusively or mostly in trees, shrubs, and bushes, off the ground
Archosauria
(\\\\\\\"ruling lizards\\\\\\\") clade of animals, partly distinguished by an antorbital fenestra, that includes the Crocodylia, Dinosauria, Pterosauria, and several other closely related groups of animals.
Arctometatarsalian
Describes the condition where the third metatarsal is pinched or compressed between the second and fourth metatarsals This condition is found in in tyrannosaurids, ornithomimids, troodontids, elmisaurids/caenagnathids, Avimimus, Mononykus and their close relatives
Arthropods
Animals with joined legs, e.g. insects, spiders, crabs and shrimps.
Articulate / Articular / Articulation
1. In anatomy, to form a joint; join
2. of fossilized bones, to remain joined as they would have been in life. Thus articular, articulation.
Asiamerica
The land areas of Asia and America joined by a land bridge formed by the Bering Straits in the Mesozoic Era.
Assemblage
A large group of fossils or other items found in the same location and regarded as being from the same time period, though not necessarily as being positioned in a manner that reflects their arrangement in life.
Assemblage zone
An aggregation of fossils in a body of sedementary rock.
Asteroid
Any of the numerous small rocky bodies in orbit around the Sun. Most asteroids reside in the “main belt” between Mars and Jupiter, but some have orbits that cross the Earth’s orbit and could strike its surface.
Astragalocalcaneum
Bone formed by the fusion of the of the anklebones astragalus (a) and calcaneum (c). This feature was developed convergently in birds and ceratosaurs
Astragalus / Astragalar
The tarsal bone that joins with the tibia and calcaneum to form the ankle joint. Thus, astragalar.
Autapomorphic
Describing an apomorphic or derived character unique in a particular species or another taxonomic group.
Authigene / Authigenic
A rock or mineral found at the site where it was formed. Thus, authigenic.
Autochthonous
Found at the place where it originated; located at its original site. [ compare allochthonous]
Autapomorph
1. Apomorph character state that is unique to a particular species or lineage in the group under consideration 2. in cladistics, an apomorphy that distinguishes a single clade
Avian
1. Describing or relating to birds (Aves). 2. Resembling birds, or in the matter of birds.