Glossary

A

Acanthocauli: juvenile corals (mostly Fungia) attached to the substrate either directly or on stalks

Acolonial corals: solitary corals that do not form colonies

Ambulacral grooves: grooves along the top of common walls between adjacent corallites

Anastomose: descriptive term for branches which re-fuse after having initially divided

Appressed corallites: corallites are so strongly inclined that one side is completely embedded in the coenosteum. Applied only to the genus Acropora. Appressed corallites are included in the state "Corallite or valley protrusion: half immersed"

Arborescent colonies: see branching colonies

Attachment scars: a scar-like patch on the central undersurface of free-living fungiids resulting from their attachment to the substrate as juveniles

Autotomy: a means of asexual reproduction due to break-up of a parent corallite. Seen commonly in Diaseris

Axial corallite: on branches which have multiple corallites, the axial corallite forms the tip of the branch and generally has a different structure to the radial corallites occurring elsewhere. The corallites of phaceloid corals are not classed as axial corallites because one corallite forms an entire branch. With the exception of the genus Acropora, in which axial corallites are normally present, axial corallites only occur consistently in Cyphastrea decadia

Axial furrow: a groove along the axis of the upper surface of some fungiids

Azooxanthellate corals: corals that do not have zooxanthellae. These are commonly found on reefs, but most are restricted to deep water, below the level of light penetration

B

Basal plate: the first skeletal element deposited by a planula larva

Bifacial: describes plates which have corallites on both sides

Bifurcated: divided into two equal branches

Bilateral symmetry: corallites have left and right sides which are essentially mirrors of one another

Bottlebrush branching: a descriptive term (equivalent to ‘hispidose’) for branching where sub-branches radiate in all directions from main branches and where corallites on sub-branches are generally elongate. Applied only to the genus Acropora

Branching colonies: any growth-form where branches are formed

Budding: a form of asexual reproduction where a ‘parent’ corallite forms one or more ‘daughter’ corallites

C

Caespitose: a descriptive term for branches which interlock similarly in three dimensions. Applied only to the genus Acropora

Calice: the upper surface of a corallite (usually a cavity) bounded by the wall

Central arch: a raised area surrounding the mouth of some solitary fungiids

Central corallite: occurs in colonies where the first corallite to grow remains distinguishable and has a central position in the colony

Cerioid corals: corals which have corallites whose centres are isolated from one another by adjoined (common) walls

Cilia: microscopic hair-like structures growing on the ectodermis of polyps or planulae and which aid mucous movement or locomotion (respectively)

Coelenteron: the body cavity of a coelenterate

Coenosteal elaborations: fine skeletal structures arising from the coenosteum (including papillae and tuberculae of Montipora)

Coenosteum: sponge-like skeletal matrix. In general, coenosteum is located between the walls of adjacent corallites but in some taxa it can form part (eg. Acropora) or all (eg. Turbinaria) of the wall itself. For this reason, the term 'extra-thecal skeleton' is used in Coral ID instead of 'coenosteum' when referring to the inter-corallite region between the corallite walls

Coenosteum pit: the point of insertion, or commencement, of septa, mostly found in Pectiniidae and Fungiidae

Coenosteum ridges: parallel or radiating ridges of coenosteum usually separating corallites in Montipora. In Coral ID these are normally included in the states "Linear elaborations

Coenosteum style: prominent projections from the coenosteum usually associated with a single corallite

Collines: skeletal ridges composed of coenosteum which separate corallites. An inexperienced user of Coral ID may have significant difficulty distinguishing between a colline and a true corallite wall. For that reason, characters in Coral ID generally examine 'wall-like structures' where collines and true walls are considered together

Colonial corals: corals composed of many individuals. There is no clear distinction (eg. in fungiids) between single individuals with many mouths and colonies of individuals with single mouths. (See also Coral Structure/Coloniality.)

Colour: colour of corals is usually due to a combination of zooxanthellae and pigments in living tissues. Colour changes with depth and with artificial lighting. Where used in identification, the light source (natural or artificial) may be important, especially at depths below 5 metres

Columella: singular of columellae

Columellae: skeletal structures at the central axis of corallites. May take various forms, including ‘spine-like’, ‘spire-like’, a ‘tangle’ of rods, or ‘spongy’ (structured like a sponge although not soft)

Columnar colonies: colonies forming one or more columns

Comb-rows: septa have inwardly projecting spines aligned vertically as in a hair comb. Occurs commonly in the Acroporidae and also in some Poritidae

Compact branching: where branches of a colony are close together

Continua: where there is no clear discontinuity in morphology, genotype or distribution

Coral: for the specific purpose of Coral ID, the term coral is short for zooxanthellate scleractinian coral

Corallite: the skeleton of an individual polyp

Corallite definition: refers to whether or not individual corallites centres can be distinguished from one another. For further discussion and illustrations see the State Information pages for the character "Corallite definition"

Corallite differentiation: refers to whether or not corallites are of one type or more then one type as occurs when there is an axial corallite or central corallite. For illustrations see the State Information pages for the character "Corallite differentiation"

Corallite isolation: refers to whether or not corallites are structurally isolated from other corallites usually by a distinct wall. For further discussion and illustrations see the State Information pages for the character "Corallite isolation"

Corallite (or valley) protrusion: refers to the degree to which a corallite (or valley) is exsert, ie. protrudes above the basal structure of the colony. For illustrations see the State Information pages for the character "Corallite or valley protrusion "

Corallum: the whole coral skeleton

Corymbose: a descriptive term for colonies which have horizontal interlocking branches and also have short upright branchlets, usually used for some Acropora species

Costae: radial skeletal elements outside the corallite wall

Cycles of septa/septo-costae: where radial elements occur in a set sequence of size (6 primary, 6 secondary, 12 tertiary and so on)

D

Day/Night tissue expansion: refers to the extent to which tentacles, mantles and vesicles change their degree of expansion from night to day. For further discussion and illustrations see the State Information pages for the character "Day/night tissue expansion"

Daytime tissue projection: refers to the extent to which all soft tissues are extended during the day. For further discussion and illustrations see the State Information pages for the character "Daytime tissue projection".

Deltas of septa: fusion of septa into a hexameral pattern of spongy columella. Common only in Goniopora

Denticles: pali-like granules on an upper surface of Porites septa

Depauperate: having a relatively small number of species

Digitate: a colony with short branches shaped like the upturned branches of a hand

Dimidiate: shape of calice rim of Acropora radial corallites where the rim is not entire (is shortened on the side nearest to the branch)

Dispersal: the process of movement of propagules resulting in dispersion

Dissepiments: blistery horizontal plates of calcium carbonate adjoining corallites

Distal: remote from the centre, eg. the end of a branch

E

Ectodermis: the outer cell layer of a polyp

Elaborations: fine skeletal structures, including papillae and tuberculae

Encrusting colonies: thin colonies which adhere closely, and are attached to, the substrate

Endemic: a species restricted to a specific region

Endosymbiotic: symbiosis where individuals of one organism (zooxanthellae in the case of extant corals) live within the cells of another

Entire: without substantial irregularities

Environmental variation: the variety of environmental parameters associated with a particular place

Epitheca: a tissue-like layer of calcium carbonate that grows outside corallite walls. Originally derived from the basal plate

Explanate corals: colonies which spread horizontally as branches fuse into a solid or near solid plate

Exsert: corallites or septa clearly project above surrounding structures

Extratentacular budding: where daughter corallites grow from the outside wall of parent corallites

Extra-thecal elaborations: fine skeletal structures, including papillae and tuberculae, on extra-thecal skeleton

Extra-thecal skeleton: a collective term used in Coral ID for the non-wall skeletal structures between the corallites which support the coenosarc (the coral tissue between the polyps). It specifically excludes any features associated with the wall, and includes all non-wall inter-corallite surface structures (costae, papillae, spines and other elaborations). Structures on the underside of a plate or on the ventral surface of free-living fungiids are excluded. The term as used here is partly, but not wholly, analagous to coenosteum

Family: the taxon level representing a group of related genera

Flabello-meandroid corals: corals which have valleys with walls that are separate from the walls of adjacent valleys

Flaring corallites: with expanding (trumpet-like) curves to the outer corallite wall. Applied primarily to the genus Acropora

Fossa: a cavity or hole in the skeleton

Foveolate corallites: corallites of some species of Montipora which are situated at the base of funnel-shaped depressions

Free-living coral: corals that are not attached to the substrate

G

Gastrodermis: the inner cell layer which lines the coelenteron

Genus/Genera: the taxon level representing a group of related species

Geographic variation: geographic variation in morphology which has a genetic basis

Glabrous: devoid of attached structures

Gonads: testes and ovaries. These are usually developed annually

Granulated: covered with sand-like particles

Groove-and-tubercle structures: fine epithecal structures, the development of which is controlled by polychaete worms. Found primarily in Faviidae

H

Hermaphrodite: individuals that are both male and female

Hermatypic: literally ‘reef building’ but commonly used as a descriptor for marine invertebrates that have photosynthetic plants living symbiotically within their tissues. Because the word is a misnomer, several terms including ‘reef-building’, ‘symbiotic’ and ‘zooxanthellate’, are used synonymously. Of these, the first two are ambiguous and the latter is restricted to extant corals other then taxa with zooxanthellae

Hermatypic corals: zooxanthellate or reef-building corals (see 'hermatypic' above for further discussion)

Hispidose: a descriptive term (equivalent to ‘bottlebrush’) for branching where sub-branches radiate in all directions from main branches and where corallites on sub-branches are generally elongate. Applied only to the genus Acropora

Holotype: the principal specimen on which a species name is based

Hybrid: an individual with parents of different species

Hybridisation: formation of a hybrid

Hydnophore: an alternative name for monticule, sometimes used with Hydnophora

I

Immersed corallites: corallites which are embedded in the surrounding skeletal matrix

Incipient axial corallites: corallites intermediate in development between radial and axial corallites of Acropora

Intratentacular budding: where daughter corallites grow from the inside wall of parent corallites, usually by division of the parent corallite

J

K

L

Labellate: shape of Acropora radial corallites where the inner wall is not formed

Lateral pairs of septa: two pairs of septa on each side of Porites corallites

M

Mantle: fleshy discs which obscure the skeleton of living corals when tentacles are not extended. Mantles may be distinct from tentacles or be partly composed of retracted tentacles. They typically partially retract when touched

Massive colonies: colonies which are broadly similar in all dimensions (have a small surface area to volume ratio) and are mostly solid beneath the surface

Meandroid colonies: colonies composed of valleys with walls that are adjoined to walls of adjacent valleys

Mesoglea: a non-cellular layer between the ectodermis and gastrodermis

Metamorphosis: the transformation of a planula larva into a polyp

Micro-atoll: a colony shaped like an atoll because low tide level permits only lateral growth

Microhabitat: a vague word indicating a particular type of habitat occupied by a coral colony

Migration: large-scale movement of a population. Synonymous with dispersion except implying an activity specific in time or space

Monocentric: corallites have a single centre and mouth

Monospecific: describes a genus with one species only, or a coral community with one species only

Monticules: conical sections of common wall between corallites which have a secondary radial symmetry

Mucus: gelatinous substance secreted by the ectodermis for protection, to aid the capture of food, or to remove sediment. Mucus is usually moved by cilia

Multicentric: corallites or valleys have more than one centre or mouth

N

Nariform: a radial corallite, usually of Acropora, shaped like an upsidedown ‘roman’ nose

Nematocysts: microscopic stinging cells occurring individually in the ectodermis or grouped into wart-like clumps on tentacles

Nomenclature, rules of: an international code for the naming of taxa

Nominal species: a species that exists in name only

O

Oral cone: a mound of soft tissue surrounding the mouth. Applies primarily to Alveopora and Goniopora

Oral disc: the soft tissue between the mouth and the surrounding tentacles

Orders of septa/septo-costae: where radial elements occur in different sizes, but not as cycles

P

Pali: upright skeletal rods or plates at the inner margin of septa formed by pourtàles plan fusions

Paliform crown: a circle of paliform lobes surrounding the columella

Paliform lobes: upright skeletal rods or plates at the inner margin of septa formed by upward growth of the septum

Papillae: projections of coenosteum on the surface of many species of Montipora that are less than a corallite in width

Paradigm: a well defined perspective on a major area of thought or knowledge

Perforate, perforated: where the skeletal matrix is not solid

Petaloid septa: primary septa which have a tapered, curved (tear-drop) shape because they are enclosed by other septa or by coenosteum

Phaceloid corals: colonial corals that have corallites of generally uniform height which are usually only adjoined towards their base. Where phaceloid corals branch, the entire branch is formed from only one corallite

Phylum: the highest taxon level normally used and usually represents a group of related classes. Classes are divided into orders, of which Scleractinia is one. There are often other taxonomic levels besides these between phylum and order

Pinnule: small upright structures, usually columellae, which are cylindrical in shape

Planula larvae/planulae: larvae of coral

Plocoid colonies: corals whose corallite centres are isolated from one another by separate walls which are at least slightly exsert

Ploco-meandroid colonies: a rare colony form where corallites are in short to long valleys whose walls are not adjoined and which are exsert from the main coral skeleton

Polycentric: corallites have more than one centre or mouth

Polymorphic species: species which have a wide range of morphological variation

Polyp: an individual coral including soft tissues and skeleton

Pourtàles plan: a cyclical arrangement of septa created by a specific pattern of fusion

Propagule: a sexually or asexually produced reproductive body capable of developing into an adult organism

Prostrate: a descriptive term for a colony which sprawls horizontally over the substrate

Proximal: close to the centre, eg. the base of a branch

Q

R

Radial corallite: corallites on the sides of branches as opposed to axial corallites on the tips of branches. The term is usually used with Acropora and Anacropora

Radii: inconspicuous septal elements connecting septa with the columella. Used in the taxonomy of Porites

Rasp-like corallites: regularly arranged corallites with sharp edges reminiscent of a wood rasp

Recessed: corallite centres are recessed into the skeleton, adjacent walls are shared and are distinctively acute

Reef-building corals: zooxanthellate or hermatypic corals

Reef flat: the flat intertidal parts of reefs that are exposed to wave action

Reef slope: the sloping parts of reefs below the reef flat

Reefs: limestone platforms of shallow tropical seas built by corals, coralline algae and other photosynthetic organisms or symbionts

Reticulate evolution: evolution dominated by sequential division and fusion of clades

Reticulation: interbreeding that creates reticulate patterns within and among species over large geographic areas

S

Satellite colonies: colonies that develop within the tissue of parent colonies and which have their own unattached skeletons. Best seen in Goniopora stokesi

Scale-like corallites: corallites forming a pattern reminiscent of the pattern of fish scales

Scleractinian corals: corals which have limestone skeletons and which belong to the order Scleractinia

Septa: radial skeletal elements projecting inwards from the corallite wall

Septal fusion: where the inner margins of some septa are fused

Septal teeth: sharp tooth-like or lobed structures along the margins of septa

Septo-costae: radial skeletal elements crossing the corallite wall, composed of both septa and costae. The septa and costae of septo-costae can be distinct from one another or can form a continuous structure in which the limits of each component are indistinct

Septum: singular of septa

Serrated: with fine (just visible) saw-like teeth

Sibling species: similar species that are assumed to be the product of relatively recent speciation

Skeletal masking: the extent to which skeletal detail is hidden by living tissue. For further discussion and illustrations see the State Information pages for the character "Skeletal masking".

Solitary corals: corals composed of single individuals. There is no clear distinction (eg. in fungiids) between single individuals with many mouths and colonies of individuals with single mouths. (See also Coral Structure/Coloniality.)

Spat: pinhead-sized single corallites that form immediately after metamorphosis of planula larvae

Spawning: the release of gametes into the water column

Species: Not closely defined. A general term loosely defining a taxonomic grouping having the range of meanings normally in the taxonomic and general literature

• Real species: A species-level operational taxonomic unit, whether named or unnamed, recognised by the authors
• Probably real species: A species-level operational taxonomic unit, whether named or unnamed, recognised by the authors but with a small degree of doubt
• Possibly real species: A species-level operational taxonomic unit, whether named or unnamed, recognised by the authors but with a significant degree of doubt
• Available name: A name that meets the requirements of the ICZN irrespective of its taxonomic status
• Accepted name: The available name which is considered to have priority over other available names for that real species
• Valid species: A real species associated with its accepted name
• Probably valid species: A probably real species associated with its accepted name
• Possibly valid species: A possibly real species associated with its accepted name
• Accepted species: a valid or probably valid species, or a species that the authors believe to be real but which is unnamed or has nomenclatural issues

Spinule: a spine of near microscopic size

Spongy: having the structural appearance of a sponge, but not a soft or pliable texture

Staghorn: common name for certain branching Acropora

Sterome: skeletal infilling derived from the thickening of septa to provide most of the content of corallite walls in some coral families

Stolons: horizontal polyp outgrowths leading from which daughter polyps are budded. Common in Astrangia

Striae: a string-like arrangement of skeletal elements or soft tissue

Style: a short solid spine tapering to a point

Sub-: a prefix meaning ‘less than’ or ‘not quite’

Symbiosis: the close association between two organisms where there is substantial mutual benefit

Synapticulae: rods linking septa, either forming a network or, in some coral families, contributing to the content of corallite walls

Syngameon: a complex of species that can interbreed. Such a complex may have no well-defined morphological characteristics

Synonymy: a list of names considered by a taxonomist to apply to a given taxon other than the name by which the taxon should be known

Systematics: study of the genetic relationship between taxa

T

Tabulate corals: a major group of non-scleractinian corals that became extinct at the close of the Palaeozoic Era

Taxon: a taxonomic unit

Taxonomy: study of the genetic relationship between taxa and the naming of taxa

Teeth: (= dentations) spines on the inner margins of septa

Tentacles: tubular extensions of the polyp. The interior of the tentacles is continuous with the coelenteron. Tentacles of the majority of corals are extended only at night

Tentacular lobe: a lobe at the beginning (point of insertion) of a septum. Commonly found in Fungia where each lobe supports a single tentacle

Terete: having a uniform diameter (not tapered)

Theca: singular of thecae

Thecae: (= walls) the tubular skeletal part of corallites

Thicket: a descriptive term for colonies composed of closely compacted upright branches

Tissue expansion: the extent to which living tissue extends away from the skeleton. Includes the length of extended polyps and usually varies diurnally

Trident: pattern of fusion of the ventral septa of some Porites where the septa are linked by a cross-bar

Triplet, of septa: the three ventral septa of Porites corallites

Tuberculae: projections of coenosteum on the surface of many species of Montipora that are more than a corallite in width

Type locality: the place from where a species was originally described

Type species: the species on which a genus is primarily based

Type specimens: the specimens from which a species was originally described. A single or principle specimen is the holotype

U

Unifacial: describes plates which have corallites on one side only

V

Valley protrusion: refers to the degree to which a valley is exsert, ie. protrudes above the basal structure of the colony

Verrucae: mounds of coenosteum on the surface of many species of Montipora and Pocillopora that are wider than a corallite

Vesicles: large grape-like sacs that are expanded during the day in some Euphyllidae

Vicariance: the process that occurs when a formerly continuous population is divided by a barrier and evolves into two or more species

W

Wall: (= theca) the tubular skeletal part of an individual corallite

Wall separation: refers to whether or not walls of corallites or valleys are separate or shared

X

Y

Z

Zooxanthellae: photosynthetic algae (dinoflagellates) that can occur symbiotically in animal tissue

Zooxanthellate corals: corals that have zooxanthellae