abdomen - in insects and crustaceans, the posterior tagmata.
Order Acrotretida - acrotretid inarticulate brachiopods, (Cambrian-Recent, 120 genera)
adductor muscles - muscles used to close the valves of a shell
agglutinated tests -in forams, a test formed by gluing pieces of sediment together. Some forams are very picky about the material they choose to form their agglutinated test.
alate - hinge extends beyond the shell to form wings
ambulacrum - radial features in echinoderms with ambulacral groove and tube feet
ancestrula - in bryozoans, the founding zooid in a colony.
Class Anthozoa - stony corals (Precam.-Rec., 2300 genera)
anus - end or exit of alimentary tract.
aperture - open end in a univalved shell
apomorphy - derived from and differing from the ancestral state, a change in a character at a branching point in a cladogram, a share derived character.
Aristotle's lantern - jaw-like element found in echinoids
+ Incertae sedis. Archaeocyatha - extinct group possibly related to sponges (230 genera)
arm - in crinoids, extension of ambulacral region branching off of the calyx, forming feeding fan.
Phylum Arthropoda - joint footed - large phylum of segmented animals including trilobites, crabs, insects, spiders, lobsters, krill, barnacles etc.
Class Articulata - articulate brachiopods (Cambrian-Recent, approx. 3200 genera)
ascon - simplest grade of organization in sponges.
Class Asteroidea - starfish (Ordovician - Recent, 430 genera)
Subphylum Asterozoa - starfish and brittle stars
astrorhizae - in sclerosponges and stromatoporoids, the raised, star shape structures on the upper side around the oscula.
apomorphy - derived from and differing from the ancestral state, a change in a character at a branching point in a cladogram, a share derived character.
autopomorphy - possession of a unique derived character by a clade.
avicularium - in bryozoans, zooid with extensions to the operculum or orifice wall to form mandible (generally used for cleaning the colony of debris, although there are other purposes, including one very strange case, where avicularium is used for locomotion of the colony).
axial furrow - groove outlining the central (axial) lobe of trilobites, separating the axial lobe from the pleural lobes.
biostratigraphy - chronostratigraphic correlation of strata using data from ranges of fossils.
biostratigraphic zones - a unit of geologic time defined by the presence (or rarely, absence) of one or more fossil species. Interval zones use the range of single species, assemblage zones use the ranges of a group of species, while abundance zones use maximum or minimum abundances instead of just presence and absence data.
biramous appendage - in arthropods, appendage with two branches. For biramous walking appendages, one branch usually contains the walking leg, while the other branch bears a gill.
bivalved - having a shell composed of two valves, e.g. molluscan bivalves, brachiopods, ostracods, etc.
Class Bivalvia - also called Pelecypoda (hatchet foot), a class of bivalved mollusks including clams, oysters, scallops, etc.
bellerophonts - an extinct group of probable gastropods with planispiral shells
benthic/benthonic - on the ocean floor
+ Subphylum Blastozoa - extinct groups of blastoid echinoderms
boring predatory - in gastropods, mostly muricids and naticids, snails which bore holes in prey using chemical dissolution and/or scraping with the radula.
brachial valve - in brachiopods, the valve to which the lophophore is attached
Phylum Brachiopoda - arm footed - lophophore bearing bivalved marine organisms, commonly called brachiopods (Cambrian-Recent)
brachidium -in brachiopods, calcareous support for the lophophore.
Phylum Bryozoa - plant animal - exclusively colonial group, commonly called bryozoans
byssus/byssal thread - in mollusks, a sticky hair-like organic structure secreted from a gland on the foot which is used to attach the animal during metamorphosis. In some bivalves, the byssus is retained in the adult form, and used to attach the animal to the substrate. The retention of the byssus seems to have evolved independently in many bivalve groups (e.g. scallops, giant clams, ark shells, pen shells, mussels, etc.). Byssate bivalves usually have a gap in the shell called the byssal gape for the byssus to protrude when the valves are closed
camera - in shelled cephalopods, the shaped between the septa of the phragmacone (not including the siphuncle)
cameral deposits - shelly material infilling the open space in chambers of shelled cephalopods, presumably to help in maintaining the animal's orientation
carapace - in arthropods, the dorsal exoskeleton.
cardinal process - raised portion in the posterior of the brachial valve to which the diductor muscles attach.
carnivores - organisms which kill other organisms and consume them. Most vagrant carnivores are also scavengers
cast - infilling of a mold
CCD -Calcium Carbonate Compensation Depth. Oceanic depth below which calcium carbonate will tend to dissolve. The depth is highly variable, and is effected by a number of different factors (e.g., rate calcium carbonate input, water temperature, etc.)
Class Cephalopoda - head footed - group of brainy mollusks, with or without shells, including ammonoids, nautiloids, squid, octopi, and cuttlefish
cephalon - head - in some arthropods, the anterior tagmata which contains the head. In some decapods, the head and cephalon are fused to form a cephalothorax
chamber -in foraminifera and shelled cephalopods, the portions of the shell defining different internal spaces.
character - an inheritable trait or feature of an organisms; binary characters have two states (e.g., present or absent), multistate characters have more than two possible states (e.g., eye color), discrete characters have a limited number of values (e.g., the number of digits in vertebrates), continuous characters have a continuous range of possible values (e.g. body size).
Superclass Chelicerata - claw horn bearing - arthropod group characterized by have chelicera (a pair of pre-oral appendages), including arachnids, horseshoe crabs, scorpions and eurypterids ("sea scorpions")
chitin - extremely tough organic compound (polysaccharide carbohydrate) used primarily in the exoskeleton of arthropods.
choanocyte - in sponges, flagellate cells which pump water through the sponge and extract food from the flow.
Phylum Chordata - cord bearing - phylum characterized by a dorsally located notochord, including vertebrates
cladistics - using morphology to come up with a logical phylogeny for biological groups. The basic unit of operation is the clade which is an ancestral species and all of its descendants (the definition of a monophyletic clade). Paraphyletic groups are all descendant from the same common ancestor, but not all descendants are included, while polyphyletic groups have more than one ancestor.
Phylum Cnidaria - nettle bearing - group of solitary and colonial predatory organisms with specialized stinging cells called cnidoblasts, and frequently having distinctive morphologies for asexual and sexual reproduction. Cnidarians include jellyfish, corals, anemones, etc.
coenosteum - the open calcareous skeleton of stromatoporoids.
coccoliths - the tiny, tiny plates of the coccosphere of coccolithophores, a major component of many calcareous nannofossil deposits
commisure - line along which the two valves in a brachiopod shell meet.
+ Incertae sedis. Conodonta - cone tooth - cone shaped skeletal elements of an unknown (probably chordate) animal (230 genera)
+ Incertae sedis Conularida - extinct group of possible scyphozoans shaped like four sided pyramids (25 genera)
coprolite - fossilized remain of animal excrement.
Superphylum Crinozoa - lily animal - sea lilies and certain extinct groups of sea lily-type animals
Superclass Crustacea - shelled, or crusty - Large group of mostly marine arthropods, including barnacles, crabs, lobsters, ostracods, the non-marine pill bugs, etc.
cubichnia - trace fossil displaying resting or nestling behavior. Emphasis on temporary resting feature. Example: Rusophycus
cuticle - in arthropods, the non-cellular exoskeleton secreted by the epidermis, usually composed of many different layers. The inner layer is usually flexible, but the middle layer of the cuticle can be hardened in places either by tanning of the chitin (caused by cross-linking the chitin proteins) or through calcification (secretion of calcium carbonate in the cuticle). The exocuticle is usually covered with a waxy layer for water retention.
+ Order Dendroidea -branching form - dendroid graptolites(30 genera)
dentition - hinge teeth and sockets.
dextral - to the right - coiling to the right. Opposite of sinistral.
diductor muscles - in brachiopods the muscles which open the shell
domichnia - trace fossil of living burrows. Commonly U-shaped or vertically oriented single burrow. Example: Skolithus
doublure - overlap of dorsal exoskeleton onto the ventral portion of trilobite exoskeletons.
Class Echinoidea - spiny sea urchin - echinoid echinoderms with most rigid tests, including sea urchins, sea biscuits, sand dollars, etc. (Ordovician - Recent, 765 genera)
Phylum Echinodermata -spiny skinned - large group of primarily pentamerally symmetrical metazoans with internal calcite skeletons, including crinoids (sea lilies), echinoids (sea urchins, sand dollars, sea biscuits), holothurians (sea cucumbers), asteroids (starfish), ophiuroids (brittle star), and many extinct groups (e.g. blastoids, edrioasteroids, etc.)
Subphylum Echinozoa - spiny animals echinoderm subphylum including echinoids, holothurians, and several extinct classes
endoskeleton - internal skeleton, usually secreted by the mesoderm (e.g. vertebrates, echinoderms)
enrollment - in trilobites, the act of rolling up, rolly-polly (pillbug, potato bug) - style. Presumably evolved as a protection against predators.
epibiont - organisms that lives attached to other organisms
epivalve -the larger valve of a diatom frustrule
escutcheon - lozenge-shaped area posterior to beak on the dorsal side of bivalve shells, sometimes defined by a ridge in the shell.
exoskeleton - external skeleton
exuviae - any part of a shed arthropod exoskeleton.
fodichnia - trace fossil displaying deposit feeding behavior, usually in shallow burrows. Frequently show spreiten. Emphasis on digging for food. Example: Chondrites
Order Foraminifera - single celled eukaryotes which make skeletons called tests. Foram tests are frequently calcareous, although both agglutinated (formed from sticking together detrital grains) and organic tests are also common. Other structures are exotic, but not unknown.
free cheek - in trilobites, the portions of the cephalon which break off from the fixed cheek during ecdysis.
fringe - in trilobites, an flat extension of the cephalon which is frequently pierced and pitted to form a lacy-appearing color (e.g., in the harpids and trinuculids).
frustrules - the bivalved silica shell of diatoms
fugichnia - trace fossil displaying escape behavior. In the case of catastrophic burial, the burrows go up as the animal tried to extract itself from the sediment.
functional morphology - study of form and function of organisms
Class Gastropoda- stomach foot - large group of torted, or secondarily detorted univalved mollusks, including snails, slug, nudibranchs (sea slugs), etc.
genal spine - posteriorly pointing extension of the cephalon to form a spine. In some groups, the genal spine is presumed to have served as an anchor during ecdysis. In other groups, the genal spines were very pronounced and elaborate.
glabella - the central region of the cephalon of trilobites, frequently raised, sometimes bumpy, bounded by occipital and axial furrows..
gill - a usually feathery structure used for gas exchange (respiration). In some groups, gills are also used for food capture
gill branch - in arthropods, the branch of a biramous appendage that bears a gill.
girdle - in polyplacophorans, the muscular oval surrounding the plates. In diatoms, the region of overlap between the hypovalve and epivalve.
grade/body plan grade - organization of body construction. From simplest to most complex: unicellular (single celled, e.g. diatoms or foraminifera), primitive multicellular (simple cell differentiation, e.g. sponges), diploblastic (two cellular germ layers - endoderm and ectoderm, e.g. cnidarians), triploblastic (three cellular germ layers - endoderm, mesoderm, and ectoderm, .e.g. most other complex animals, including humans)
+ Class Graptolithina - painted stone - group of colonial (probable) hemichordates with a chitinous skeleton (periderm), commonly preserved as carbon films in black shales (240 genera)
+ Order Graptoloidea - graptoloid graptolites (185 genera)
Class Gymnolaemata - group of bryozoans characterized by box-shaped zooids (Ordovician-Recent, 1050 genera)
herbivore - organisms which consume plant matter for food
hermatypic corals - corals with zooxanthellae
heterotrophes - organisms which must eat other organic matter for food, e.g. herbivores, carnivores, scavengers, suspension feeders, detritovores, etc.
Class Hexactinellida - "glass sponges" (295 fossil genera)
hinge - in brachiopods and bivalves, the area where the two valves of a bivalved shells are joined, and rotate past each other.
holapsid period - in trilobites, ontogenetic stage defined by the number of segments present.
holochroal eye - in arthropods, a compound eye.
+ Subphylum Homalozoa - group of primitive, extinct echinoderms
hyaline test - foraminiferal test microstructure with "glassy" appearance.
Class Hydrozoa - anthozoans characterized by true alteration of generation between sexually reproducing medusa and asexually reproducing hydroids, includes fire coral, common stinging hydroids, Portuguese Man-of-War (a colonial medusoid), etc. (Precam.-Rec., 500 genera)
hypovalve -the smaller valve of a diatom frustrule
ichnogenera - systematic classification of ichnofossils comparable to the generic level in biological nomenclature. Examples: Cruziana, Skolithus, Zoophycus, etc.
ichnology - study of ichnofossils
ichnogenera - systematic classification of ichnofossils comparable to the species level in biological nomenclature.
Class Inarticulata - inarticulate brachiopods (Cambrian-Recent, approx. 220 genera)
intervallum -chambers defined by septal walls in space between inner and outer cones in archaeocyathans.
laminae - single layer in very fine scale layering.
leucon - most complex grade of organization in sponges.
ligament - in molluscan bivalves, a non-calcified, elastic structure which joins the two valves of the shell on the dorsal side
Order Lingulida - a group of fingernail shape, fluorapatite shelled, burrowing inarticulate brachiopods (Cambrian-Recent, 85 genera)
lophophore - in lophophorates (brachiopods, bryozoans, and phoronids) a specialized respiratory and food capture organ
lunule - depression in the along the dorsal side of some bivalve shells, anterior to beak.
medusa - in cnidarians the free living, pelagic phase. The medusa usually reproduces sexually
merapsid period -ontogenetic stage of trilobite development between appearance of transverse joint in exoskeleton until a species specific number of segments have been developed (at which point, the trilobite is in the holapsid stage of development).
mold - impression of organism preserved in rock. External molds are impressions of the outside of a structure, while internal molds (sometimes called "steinkerns") are impressions of the inside of structure. Composite molds are formed when the original material dissolves, and the external and internal mold are pressed together. Both external and internal features are preserved on a composite mold
Phylum Mollusca - soft animals - originally any soft bodied marine organism, now limited to gastropods, bivalves, cephalopods, scaphopods, rostroconchs, polyplacophorans (chitons), and several other groups
monophyletic group - all descendants of a common ancestor.
Class Monoplacophora - single shelled - group of primitive single celled mollusks, formerly known only from the fossil record
morphology - body form and shape
monticule - in stenolaemate bryozoans, a cluster of zooids that forms a raised area on colony surface. Used to control incurrent and excurrent flow over colony surface.
myostracum - shell laid down beneath muscle areas in mollusks
neritic - 0-200 meters water depth
Ophiuroidea - brittle stars (Ordovician - Recent, 325 genera)
opisthostoma - in chelicerates the posterior tagmata
+ Order Orthida - orthid brachiopods(Cambrian- Permian, 340 genera)
orthoconic - straight shelled.
osculum - (pl. oscula) in sponges, excurrent opening
ossicles - small echinoderm small skeletal
ostium - (pl. ostia) in sponges, incurrent opening
Class Ostracoda - small crustacean arthropods with dorsally located bivalved carapace which is commonly heavily calcified (approx. 1900 genera)
ovicell - in cheilostome bryozoans, a brood chamber.
paleoecology - study of the relationship between organisms and their environment.
pallial line - line along the inside margin of molluscan bivalve shell where the mantle tissue is attached to the shell.
pallial sinus - an indentation in the posterior portion of the pallial line of siphonate bivalves where the siphon attach to the shell
pascichnia - trace fossil displaying grazing behavior, usually along sediment/water interface. Analogous to strip mining. Emphasis on grazing. Example: Nereites
pinnule - in crinoids, slender branchlet attached to arm.
pedicle -fleshy "stalk" protruding from the posterior of brachiopod shells. In articulate brachiopods and non-lingulid inarticulates, it is usually used to attach the brachiopod to a surface.
pedicle valve - in brachiopods, the valve to which the lophophore is not attached and the pedicle muscle is attached.
+ Order Pentamerida - pentamerid brachiopods (Cambrian-Devonian., 160 genera)
pelagic - in the water column
periostracum - in bivalves, the organic, horny layer of tissue on external portion of the shell.
photic zone - water depth to which significant sunlight penetrates. It varies greatly with the amount of suspended material in the water column, but is generally less than 180 m
phragmacone - in shelled cephalopods, the chambered portion of shell
phylogeny - ancestral history of a clade
pillar - vertical, rod-like structures in stromatoporoids.
planispiral - coiling in one plane (e.g. bellerophonts, most coiled cephalopods)
planktic/planktonic - free floating in the water column
plate - in echinoderms, a tabular ossicle.
pleura -in trilobites, the lateral portions of thoracic or pygidial segments.
polymorphism - many forms - in colonial organisms, differentiation of different individuals to perform specialized tasks
polyp - in cnidarians usually attached, somewhat cylindrical form with mouth facing away from the attachment surface. In most groups, the polyp form can bud asexually, while in some groups, the polyp form can also reproduce sexually.
polyphyletic group - a group that contains descendants of different ancestors.
porcelaneous test - distinctive foram calcareous test morphology found primarily in miolinids, consisting of imperforate walls without pores. Under reflective light, porcelaneous tests have a milky white appearance similar to porcelain china.
protapsid period - in trilobites, very early ontogenetic stage in which there is no transverse joint in the exoskeleton. Followed by the merapsid period.
protoconch - the first portion of the shell. In gastropods, the protoconch sometimes displays a different morphology from the younger portions of the shell, frequently indicating a change in life habit.
pseudoraphe - silicified area clear of punctatae running down the center of pennate diatoms.
Class Polyplacophora many shelled - chitons, mollusks characterized by shell composed of 8 dorsally located plates
Phylum Porifera - many holed - sponges
prosoma - in chelicerates the anterior tagmata
protoconch - the oldest whorls in a gastropod shell, i.e. the juvenile shell form. Snails sometimes have different morphologies between the protoconch and the adult shell, which sometimes indicates that the juvenile and adult had different life habits
pseudobivalved - usually referring to rostroconchs, the shell has two valves, but no articulating hinge, and therefore the shell can not open (there are gaps at the anterior and posterior ends in rostroconchs)
punctae - in brachiopods with fibrous shells, small pores in the shell. Brachiopods with punctae are termed punctate
pseudopunctae - in brachiopods with laminar shells, slender rods of calcite in the shells which superficially resemble puctae
raphe -unsilicified groove down center of each valve in pennate diatoms
repichnia - trace fossil displaying moving behavior, either along a surface, or along a shallow burrow. Emphasis on movement. Example: Cruziana
replacement - original organic matter replaced by a different mineral (e.g. pyritization, silicification, etc.)
recrystallization - biominerals recrystallize to more stable mineralogies
rhabdosome - graptolite skeleton
rhizopoda -class containing foraminifera
Order Rhynchonellida - rhynchonellid articulate brachiopods (Ordovician-Recent, 520 genera)
+ Class Rostroconchia - extinct molluscan group
+ Order Rugosa - wrinkled skin extinct group of mostly solitary, but some colonial stony corals (800 genera)
rudists - a very unusual extinct group of frequently very large bivalves in which one valve is elongate and cone shaped, while the other is a simple camp
Order Scleractinia hard corals solitary and colonial modern stony corals (600 genera)
schizochroal eye - in arthropods, aggregate eye.
Class Scyphozoa - cup animals - cnidarian group characterized by the dominance of the medusa, including most jellyfish (Precam.-Rec., 90 genera)
segmentation - division of body into a number of similar segments.
septa/septum (sing.) - in cnidarians vertical walls within the corallite that subdivides the internal digestive cavity. In shelled cephalopods the dividers between the chambers of the shell
sinistral - to the left - coiling to the left.
siphuncle - in shelled cephalopods, the buoyancy control tube that penetrates the otherwise sealed chambers of the shell.
siphons - tubes for bringing water toward and animal (incurrent siphons) and away from the animal (excurrent siphons). The siphon in cephalopods are also used for propulsion
sister group - two monophyletic groups (clades) coming off of a single branching point, the most closely related clades.
spicules - the small, skeletal elements of sponges, secreted by specialized cells called sclerocytes. Spicules range in morphology from simple needles to complex, three dimensional radiating structures. Also used for needle-shaped skeletal elements in other organisms (e.g., polyplacophorans).
Order Spiriferida - spiriferid brachiopods (Ordovician-Jurassic, 720 genera)
spondylium - spoon-shaped feature found in pentamerid brachiopods
spongocoel - in sponges, a large internal space through which water flows. Also called an atrium
spongin - tough organic scleroprotein skeletal material secreted by sponge spongocytes.
statoblast - in bryozoans, bud formed on funiculus of parent zooid to form new colony.
Class Stenolaemata - group of bryozoans characterized by long, tube-like zooids (Ordovician-Recent, 750 genera)
stereom - distinctive microscopic structure of girders and struts which is characteristic of echinoderm skeletal elements
stolon - in bryozoans (particularly ctenostomates) extension from which autozooids bud.
+ Class Stromatoporata - extinct group of presumed sponges which superficially resemble stromatolites (70 fossil genera)
stromatolite - microlaminated structure formed from the life activities of algal mats.
strophic/astrophic - strophic hinge lines are straight, while astrophic hinges are curved, and there is no straight hinge line
+ Order Strophomenida - strophomenid articulate brachiopods(Ordovician-Triassic, 865 genera)
suspension feeder - organisms which capture food suspended in the water column. Suspension feeders that use a filter to capture food (e.g. crinoids, brachiopods, etc.) are called filter feeders
suture - in shelled cephalopods, where the suture attaches to inside of the shell. Sutures can only be seen when the outside of the shell has been removed, and suture pattern is used to characterize many ammonoid groups. orthoceratitic sutures are broadly curved, like modern Nautilus, agoniatitic sutures have a few lobes and saddles (as few as one lobe and one saddle), goniatitic sutures are more complex, usually with 8 lobes, ceratitic sutures are similar to goniatitic sutures, but with the lobes have a saw-toothed pattern, ammonitic sutures are extremely complex with subdivided and rounded lobes and saddles
sycon - intermediate grade of organization in sponges.
sympleisiomorphy - possession of an ancestral feature, a shared primitive character.
synapomorphy - in cladistic analysis a character that is an evolutionary innovation at a particular node
tabulae - in the stony corals tabulae are little "floors" within the skeleton of single corallites. The tabulae are most organized on a colonial basis in the tabulate corals, but are also present in rugosan and scleractian corals. Also used for horizontal skeletal structures in stromatoporoids and other groups.
tagmata - groups of specialized segments in arthropods (e.g. insects have 3 tagmata, a head, thorax, and abdomen)
taxodont dentition - composed of a row of many small teeth perpendicular to hinge margin.
Order Terebratulida - terebratulid articulate brachiopods (Devonian-Recent, 540 genera).
test - skeletal structure of foraminifera.
thorax - in arthropods with three tagmata, the middle tagmata is the thorax.. In decapods, the thorax and cephalon are sometimes fused to form a cephalothorax
torsion - in gastropods, the rotation of the posterior part of the body above the anterior portion. Torsion refers is an adaptation for fitting the soft parts of the animal more tightly into the shell, and does not refer to the morphology for the shell itself. Several gastropod groups (e.g. nudibranchs) have lost the shell, and subsequently become "detorted"
trace fossils - see ichnofossils
Superclass Trilobitomorpha - trilobites and trilobite-like arthropods
tube feet - in echinoderms, small hydrostatic structures used primarily for locomotion and food capture, but also for sensory, respiratory, and food capture, part of the echinoderm water vascular system
uniramous - in arthropods, an appendage with only one branch, as opposed to biramous.
water vascular system - internal system of fluid bearing tubes characteristic of echinoderms, and serving multiple functions. Water is pumped in and out of the system through either a hydropore (single opening) or madreporite (plate with multiple openings which looks like a kitchen sink drain) at the end of the stone canal. The system consists of a ring canal from which radial canals radiate. The radial canals are attached to ampullae, which are in turn attached to tube feet.
whorl - on complete rotation in a coiled shell
zooid - single individual in a bryozoan colony, sometimes highly specialized. e.g., kenozooids zooids used as skeletal filling (lacking most internal organs), autozooids feeding zooids.
zooxanthellae - symbiotic algae that live in the body tissues of another animal. Organisms with zooxanthellae (e.g. hermatypic corals, tridachnid clams, etc.) can use the waste products of their symbiote to increase the rate of calcium carbonate precipitation