Glossary of Terms


acetabulum - Socket in pelvic girdle at point where ilium, ischium and pubis meet, and into which the head of the femur articulates

alisphenoid - A winglike bone forming part of the lateral wall of the braincase. It also forms part of the posterior wall of the orbit. Frequently fused to the basisphenoid.

allantois - An extraembryonic membrane of reptiles, birds, and mammals. Saclike outgrowth of tissue that extends outward from the gut of a developing embryo. In mammalian embryos it is situated between the chorion and amnion and functions in respiration, excretion, and nutrition.

alveolus - A socket in which the root of a tooth is set.

altricial - Pertaining to newborn mammals that require prolonged parental care for survival.

angular process - The posterior ventral projection of the dentary below the condyle.

anterior - To the front, foremost, furthest from the tail.

antitragus - A lobe near the base of the outer margin of the pinna.

antler - A deciduous bony head ornament of any member of the family Cervidae.

antorbital pit - A pit or depression just in front of the orbit.

antorbital fossa - An extensive opening just in front of the orbit.

astragalus (= talus) -  bone of the hindlimb between tibia, fibula and calcaneum.

auditory bulla (Tympanic bulla) - The inflated bony capsule that encases the middle and inner ear.

auditory meatus - The external opening into the auditory bulla.

awns - Guardhairs with relatively uniform length with slender bases and expanded tips.


baculum - a bone in the penis of certain mammals

basal length - From anterior border of median incisive alveoli to mid-ventral border of the foramen magnum.

basilar length - From posterior border of median incisive alveoli to mid-ventral border of foramen magnum.

basisphenoid - A median ventral bone lying anterior to the occipital and between the auditory bullae.

bifurcated - two-pronged, forked

bipedal - Pertaining to locomotion on only two legs.

brachiation - A method of locomotion involving movement by swinging from one handhold to another

brachydont - low-crowned; any tooth whose width exceeds the height of the crown above the alveolus.

buccal - On the cheek side of the teeth.

bunodont - low crownded squarish teeth, capped with enamel, and possessing four major cusps arranged in a rectangle (as in pigs and humans).


calcar - A bony or cartilaginous spur arising from the ankle, and in bats, helping to support the uropatagium.

calcaneum - Calcaneus. The heel bone, the largest and posteriormost tarsal bone.

camber - curvature of the wing in bats or birds that increases drag & lift

canine - an enlarged tooth between the incisors and premolars; usually a large stabbing tooth, occasionally bladelike, but sometimes small and similar to the teeth preceding it. Absent in rodents.

caniniform - bearing a resemblance to the shape and appearance of a canine tooth.

cannon bone - Fused metatarsals or metacarpals.

capitulum - Small head or bony prominence on a bone

carnassial pair - shearing; in the Carnivora the term refers to the last upper premolar (P3) and the first lower Molar (m1).

cartilage - Gristle; a semi-elastic tissue (proteine & mucopolysaccharides), often later becoming ossified.

cartilaginous - Consisting of cartilage.

caudal - pertaining to the tail

cementum - The layer of bonelike material covering the root of a tooth.

cervical - Of or pertaining to the neck.

cervix - tip of the uterus that sometimes projects into the vagina

cheek-teeth - the premolars and molars together.

chorion - The outermost extraembryonic membrane of reptiles, birds, and mammals. In eutherian mammals the chorion contributes to the formation of the placenta.

cingulum - A prominent girdle around the base of a crown of a tooth just above the alveolus.

clavicle - A ventral bone of the pectoral girdle. Reduced or absent in many mammals. The collarbone in humans.

cline - A gradual and sequential change of characters without significant break such as would justify division into separate species.

cloaca - Chamber into which digestive, reproductive and urinary systems empty, and then exit the body.

coccyx - A small bone terminating the vertebral column in apes and humans, formed by a fusion of four rudimentary vertebrae.

conch - the external ear, the ear shell.

condylobasal length - from anterior border of median incisive alveoli to plane of posterior border of occipital condyles.

convergence - The occurrence of similar derived characters arising independently in two only distantly related groups

columella - Bone that transmits vibrations from the tympanum to the inner ear in reptiles, birds, and anurans; homologous to the hyomandibular of fishes and the stapes in mammals.

coronoid process - the most dorsal part of the mandible, the part of the vertical ramus dorsal and anterior to the condyle.

corpora quadrigemina - Four oval masses that serve as centers of optic and auditory reflexes and form the dorsal part of the mesencephalon in the brain of mammals.

corpus luteum - a mass of yellowish, glandular tissue formed from the Graafian follicle after ovulation.

costal - Of or pertaining to a rib or costa.

cranium = braincase - the part of the skull that houses the brain.

crown - The portion of the tooth extending above the gumline.

cursorial - Pertaining to running locomotion.

cusp - A peak or rounded elevation on the crown of a tooth (Example: hypocone)

cuspidate - having cusps.


dactylopatagium - In bats, membrane that fills space between the digits of the forelimb: d. minus (between digits II and III), d. longus (between digits III and IV), d. latus (between digits IV and V)

deciduous - shed periodically. In mammalian terminology this term refers to the milk incisors, canines, and premolars that are shed once and replaced by the permanent dentition.

dental formula - A convenient way of designating the number and arrangement of mammalian teeth; for example: I 3/3 C 1/1 P4/4 M 3/3 = 44 the  ancestral complement of eutherian teeth.  The letters indicate incisors, canines, premolars in upper and lower jaw in one side of the skull. The number after the equal sign indicates the full complement of teeth in both sides of the skull.

dentary bone - The lower jaw bone, constituting one half of the lower jaw or mandible.

dentine - ivory=like substance beneath the enamel, usually constituting he bulk of a tooth.

diaphragm - a septum dividing the abdominal and thoracic cavities.

diastema - A vacant space, or gap, between teeth.

digit - Any finger or toe.

diphyodont - having two sets of teeth: a milk or deciduous set and then a permanent set.

diprotodont - condition that exist in the Paucituberculata and Diprotodonta. The lower jaw is shortened and the first lower incisors are greatly elongated to meet the upper incisors.

dispersal - the permanent emigration of individuals from a population

distal - Further from the medial axis or point of attachment or origin.

diurnal - Pertaining to the daylight hours; opposite of nocturnal

dorsal - On the back.


edentulate (edentate) - Lacking teeth.

emarginate - with a notch or series of notches

enamel - Extremely hard outer layer on the crown of a tooth. consiting of calcareous compounds

entotympanic - Bone surrounding the middle ear cavity.

epipubic bones - Paired bones that project anteriorly from the pelvic girdle into the abdominal body wall of most marsupials and monotremes.

estrus - A period of time when female mammals will acccept males and mating occurs. In specific terms, when ovulation occurs. At this time, the pituitary output is predominantly LH and the newly formed corpus luteum in the ovary is producing large quantitites of progesterone.

external auditory meatus - canal leading from the surface of the head to the tympanic membrane.

external nares - the bony external or anterior aperture of the nasal cavity.


fallopian tube - See oviduct

femur (pl. femora) - The thigh or proximal leg bone.

fenestrate - Having perforations or openings.

fibula - Lateralmost of the two bones in the lower (distal) portion of the pelvic limb.

fimbriated - Having a fringed or fringe-like border.

foramen (pl. foramina) - A perforation through a bone for the passage of a nerve or blood vessel.

foramen magnum - The opening of the skull through which the spinal cord emerges.

folivorous - Leaf-eating.

follicle stimulating hormone (FSH) - A pituitary hormone that causes follicles to increase in size and, together with LH, toproduce estrogen and bring about ovulation.

fossa - A pit, depession, trough, or extensive opening.

fossorial - Pertaining a subterranean (burrowing) to life style (Examples: moles, mole rats).

frog - A pad in the central area of a hoof.

frontal - the anterior-most pair of bones covering the brain, situated between the orbits. Actually paired, but often fusing together at an early age.

frugivorous - Fruit-eating.


glenoid fossa - See mandibular fossa.

Gloger's Rule - An ecological rule that states that races of mammals in arid regions are lighter in color than related races in humid regions.

granivorous - Seed or grain-eating.

graviportal - Pertaining to a limb structure adapted for supporting great weight (e.g. elephents)

gular - Pertaining to the throat (Example: gular pouches in emballonurid bats).

gymnures - Asian hairy members of the family Erinaceidae


hallux - The first digit of the pes (foot), the big toe; frequently opposable in arboreal mammals.

hamulus - a hooklike spine on the posyterior cormer of the pterygoid bone.

heterodont - having teeth differentiated into various types, i.e. incisors, canines, premolars, and molars.

herbivorous - Feeding primarily on vegetation.

holotype - A single specimen that is the type-specimen of a particular named species or subspecies.

homodont - having teeth that are all essentially similar, usually simple cones (secondary homodonty in odontocete whales)

hoof (pl. hoofs or hooves) - The digital keratinization in unguligrade mammals, a horny sheath completely encasing the tip of the phalanx and usually providing the animal's only point of contact wiht the substrate.

humerus - The proximal bone of the fore limb, the upper arm.

hypsodont - teeth with high crowns; usually rootless and ever-growing.


illium (pl. ilia) - Most dorsal of the three bones in each half of the pelvic girdle. The pelvic bone which articulates with the sacral vertebrae.

imbricate - Overlapping as the shingles of a roof

implantation - The attachment of the embryo to the uterine wall of the female mammal.

Inc. Sed. (Incertae Sedis) - In an uncertain position. In classification, relationship of taxon to other taxa not known.

incisive foramina - A pair of openings piercing the palate behind the incisor teeth.

incisors - Nipping or chiselling teeth at the front of the jaws. Upper incisors are always rooted in the premaxillary bone.

incus - The middle ear ossicl eof mammals, situated between malleus and stapes. Derived from the quadrate bone of more primitive vertebrates.

infraorbital foramen - same as above, used when the maxillary is thin and the passage has no length.

inguinal - Pertaining to the region of the groin.

interdigital - Situated between the fingers.

infraorbital canal - A passage from the anterior face of the orbit to the side of the rostrum, passing through the base of the maxillary process.

internal nares - the internal or posterior bony opening(s) of the nasal cavity

interorbital region - The portion of the cranium lying between the orbits dorsally.

interparietal - An unpaired bone at the rear of the cranium located between the parietals and above and anterior to the occipital..

ischium (pl. ischia) - most posterior and ventral of the three bones of the pelvic girdle.


jugal - The bone that forms the midsection of the zygomatic arch.


karyotype - 1. Morphological characteristics of the chromosomes of a cell.
2. An arrangement of chromosomes of a cell according to shape, centromere position and number.


labial - On the side next to the lips.

lacrymal - A small bone in the anterior face of the orbit.

lacrymal foramen - A foramen in the lacrymal bone through which the tear duct drains into the nasal cavity, usually near the anterior margin of the orbit.

lambdoidal crest (occipital crest) - A transverse bony ridge across the cranium near the posterior border of the parietals.

larynx - A sound-producing organ in amphibians, reptiles and mammalslocated at upper end of the trachea; a cartilaginous structure containing vocal cords (the voice box).

lateral - Situated to the side of the main axis.

least interorbital breadth - The least width between the orbits dorsally.

lingual - On the side next to the tongue.

longitudinal - Lengthwise, running in a head to tail direction.

loph - A transverse ridge of enamel across a tooth.

lophodont - Teeth whose crowns have a series of lophs.

lumbar - Of or pertaining to the region of the loin.

lutenizing hormone (LH) - Pituitary hormone responsible for the formation of the corpus luteum; together with FSH this hormone stimulates the follicle to secret estrogen.


malleus - the outermost of the three ear ossicles; derived from te articular bone.

Mandible - The lower jaw, composed of the two dentaries in mammals.

mandibular condyle - The part at the rear of the mandible that articulates with the upper jaw.

mandibular fossa (glenoid fossa) - The trough in the squamosal bone for the reception of the mandibular condyle of the dentary.

mandibular symphysis - The suture between the paired dentaries.

manus - The forefoot or hand.

mastoid breadth - The greatest width across the mastoid processes measured at right angles to the long axis of the skull.

mastoid process - Bone, if present, located just beneath the auditory bulla

maxillary - The bone in the upper jaw that bears the canine, premolar, and molar teeth.

maxillary plate - That part of the maxillary bone that forms the flat plate-like anterior part of the zygomatic arch; the zyomatic process of the maxillary.

meatus - A passage or, more restricted, its opening.

medial - Situated in the middle.

mesaxonic foot - type of foot structure where the main weight is suppported by a single digit.

metacarpal - One of the five long bones connecting the wrist to the fingers.

metatarsal - Any one of the bones in the pes between the tarsals and the phalanges, one metatarsal per digit.

milk tooth - Any tooth in the deciduous set of mammals with diphyodont dentition. Replaced by permanent teeth.

molars - The posterior teeth in the upper and lower jaws that are nondeciduous.

muzzle - the snout; the nose and jaws of an animal.


nares - the openings of the nasal cavity.

nasal - the anteriormost pair of middorsal bones forming the roof of the nasal passage

nasal septum - A thin, median, vertical partition of bone that divides the nasal cavity into right and left halves.

nectivorous - feedng on nectar.

nomenclature - the scientific naming of animals.

nuchal - pertaining to the back of te neck.


occipital - The bone surrounding the foramen magnum and bearing the occipital condyles. Formed from 4 embryonic elements, the basioccipital below, 2 exoccipitals, and the supraoccipital above.

occipital condyle - A knob on either side of the foramen magnum that articulates with the first vertebra.

occipital crest - See lambdoidal crest.

occiput - The hinder portion of the skull above the foramen magnum.

occlusal surface - The crown of the tooth; the grinding surface that faces against the tooth opposing it.

orbit - The bony socket that contains the eyeball.

orbitosphenoid - Portion of the sphenoid that is visible in the wall of the orbit.

os falciforme - (falciform bone) accessory skeletal element of the hand of moles (Talpidae; "6th digit")

ossified - Hardened by the deposition of calcium, into bone.

oviduct - The duct that carries the eggs from the ovary to the uterus. Inhuman anatomy the term Fallopian tube is used.


palatal bridge - The solid posterior border of the palate in many Arvicolinae (Microtinae) which seems to bridge over the two troughs or rows of foramina that pass forward from the bridge to the incisive foramina.

palatal length - From the anterior border of the median incisive alveoli to the posterior border of the palate (not including the spine).

palatal pit - A depression in the lateral border of each palatine bone near the posterior molar.

palatal process - The portion of either the premaxillary or the maxillary bone that contributes to the formation of the hard palate.

palatal spine - A median spine projecting posteriorly from the rear border of the palate.

palate - The bony roof of the mouth composed of parts of the premaxillary, maxillary and palatine bones.

palatilar length - From the posterior border of the median incisive alveoli to the posterior border of the palate (not including the spine).

palatine - Paired bones that form the posterior part of the hard palate, and wall the anterior part of the interpterygoid fossa.

palatine vacuity - An irregular fenestration or perforation of the palatal portion of the palatine bone.

parietal - Paired bones roofing the posterior part of the braincase.
patagium (pl. patagia) - The flight membrane in bats.

pectoral - Pertaining to or situated upon the chest (Example: pectoral mammae).

pes - The hind foot. Collectively the tarsals, metatarsals and phalanges of the pelvic limb.

phalanx (pl. phalanges) - One of the bones in a finger.

phylogeny - The evolutionary history of an animal.

pinna (pl.. pinnae) - External ear.

plagiopatagium - The membrane forming the wing of a bat.

plantigrade - Feet in which parts enclosing the phalanges and metatarsals all touch the ground. For ambulatory (walking) locomotion.

polyembryony - The development of more than one individual from a fertilized ovum (Example: Dasypus novemcinctus, 9-banded armadillo)

polyprotodont - Condition found in the Didelphimorphia and Peramelina in which the lower jaw is not shortened and the anterior lower incisors are not greatly elongated.

postorbital bar - A bony bar between the orbit and the temporal fossa, formed by the union of the two postorbital processes.

postorbital process - A projection from either the jugal bone on the zygomatic arch, or the frontal bone, partially separating the orbit and the temporal fossa.

postglenoid length - From the plane of the posterior border of the mandibular fossa to the posterior tip of the occipital condyles, measured along the main axis of the skull.
pregenital - Anterior to the genital organs.

prehensile - Structures adapted for grasping or seizing by curling or wrapping around such as the tail of some American monkeys and oppossums.

premaxillary - Paired bones in the front of the upper jaw that bear the incisor teeth.

premolars - Deciduous teeth, posterior to the canines.

presphenoid - An unpaired median bone in the floor of the interpterygoid fossa, with two lateral wings, sometimes called orbitosphenoids, that form part of each orbit.

prismatic - With a pattern consisting of sharply angled triangles, or loops with sharp salient angles. Geometric in appearance (example: Microtus cheek teeth)

procumbent - Pertaining to teeth that slant forward, such as the incisor teeth of a horse.

propatagium - In bats, thin web of skin that extends from the shoulder to the wrist anterior to the upper arm and forearm.

proximal - Closer to the median axis or point of attachment or origin.

pterygoid - paired bones, sometimes fused to the basisphenoid and alisphenoids, that form the walls of the posterior part of the interpterygoid fossa.

pubic symphysis - Midventral plane of contact between the two halves of the pelvic girdle.

pubis - Either of the pair of bones forming the anterior ventral portion of the pelvic girdle.


race, local race - A subspecific group of animals all differing in the same minor characters from other comparable groups wthin the species, each group usually associated with a particular locality or set of ecological conditions.

radius - one of the two bone of the forearm.

ramus - one of the two branches of the mandible.

reticulate - net-like

rostrum - The portion of the skull anterior to the orbits.


sacral - Of or pertaining to the sacrum - the region of the vertebral column between the lumbar and the caudal vertebrae.

sagittal crest - A longitudinal median bony ridge dorsal to the braincase. Often formed by a coalescence of temporal ridges.

salient angle - The outward-projecting sharp angles on the sides of certain types of hypsodont teeth.

saltatorial - Adapted for leaping locomotion.

sanguinivorous - Feeding on blood.

scansorial - Pertaining to arboreal mammals that climb by means of sharp recurving claws. e.g. tree squirrels.

scapula - The shoulder blade. The dorsalmost bone in the pectoral girdle of mammals.

scavenger - an animal that feeds on dead animals matter that it has not killed (carrion)

secodont - cheek teeth with a cutting or shearing action adapted for a carnivorous diet.

selenodont - Teeth with longitudinal crescentic ridges of enamel.

septum - a dividing wall separating two cavities.

sigmoid - S-shaped

sphenoid - Alternate name for the basisphenoid, especially when fused with the alisphenoid and pterygoids.

squamosal - A fan-shaped bone on either side of the braincase above the auditory bulla.

stapes - The innermost of the three middle ear ossicles. A small stirrup-shaped bone derived from the columella of reptiles.

sternebra - A segment of the sternum before complete ossification.

sternum - The breastbone. A ventral structure of bone and cartilage with which the pectoral girdle or ribs or both articulate.

sulcate - bearing grooves, grooved.

supraorbital ridge - A beadlige ridge bordering the orbit dorsally.

suture - An immovable line of union between two bones.

symphysis - An immovable articulation between the ends of two bones meeting at the midine of the body.

syndactylous - Pertaining to two or more digits that are fused together.


taxonomy - the systematic arrangement of the animal (or plant) world in a natural order of evolutionary relationship. It is necessarly closely associated with nomenclature.

tarsal bones - Series of bones in the ankle. They are distal to the fibula and tibia and proximal to the metatarsals.

temporal fossa - The large space between the orbit enclosed by the zygomatic arch and the postorbital processes.

temporal ridge - A ridge traversing the top or side of the braincase, marking the dorsal border of the insertion of the temporal muscle. They may be found on parts of the frontal and parietal bones and sometimes on the squamosal. They may fuse to form a sagittal crest.

thoracic - Appertaining to or situated upon the chest.

tibia - one of the two bones forming the lower leg; the shin bone.

tine - Any one of the spikes or prongs of the antler.

trachea - In vertebrates a cartilaginous tube leading from the larynx to the bronchi through which air passes to the lungs.

tragus - The projection from the lower medial margin of the pinna in most microchiropteran bats.

transverse - in a direction across the body from side to side.

tricuspid - having three cusps.

trifid - Divided into three parts by two notches

tuberculate - WIth rounded elevations or tubercles.

tuberculosectorial - Primitive teeth consisting of cusps arranged in asymetrical triangles, the lower ones having a low heel behind.

turbinal - Any one of the several scroll-like ethmoid bones in the nasal cavity.

tympanic - the bone that forms the auditory bulla.

type - The specimen used in the original description as the basis of naming a new species or subspecies. More properly referred to as the holotype.

type locality - The exact locality from which an orignal type specimen came.


unicuspid - A tooth bearing only a single cusp. In shrew the term refers to the series of three, four, or five small pointed teeth in the jaws behind the enlarged anterior pair.

uropatagium - Skin membvrane extending between the hindlegs and frequently enclosing the tail - especially in bats.


vacuity - opening or perforation in a bony plate

ventral - Pertaining to or on the abdominal side; on the underside of an animal as opposed to the back (dorsal).

vestigial - Small or degenerate.

vibrissa - A stout, stiff and generally very long, tactile bristle growing singly or in small clusters, mostly in a few constant and well-recognized sites on the body.

vomer - A median unpaired bone lying in the floor of the nasal cavity above the hard palate.


zygoma (pl. zygomata) - See zygomatic arch.

Zygomatic arch - The arch of bone that forms the lateral border of the orbit and temporal fossa.

zygomatic breadth - The greaest width across the zygomata, measured at right angles to the long axis of the skull.

zygomatic plate - The zygomatic process of the maxillary bone when this process is in the form of a thin plate.

zygomatic process -A process of either the maxillary or squamosal bone that contributes to the formaio of the zygomatic arch.

zygote - The fertilized egg.

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