Glossary
Terminology Description
Terminology Description
Abiotic environment The physical factors that affect an organism such as light, temperature, water and its dissolved and suspended materials, and nutrients.
Acropora The dominant genus of the family Acroporidae. The species Acropora constitutes almost half of all the true corals and creates the major deposits of calcium carbonate (CaCO3).
Ahermatypic Corals that lack endosymbionts (zooxanthellae) and do not contribute to reef-building.
Alcyonacea The order of soft corals. They are cnidarian and live in shallow water. Most of the specimens are tropical and soft-bodied and found in all areas.
Alcyonaria An order of cylindrical polyps found in all marine environments. The largest distribution is in tropical waters where many harbor symbiotic zoochlorellae or zooxanthellae algae, which can add colour to them.
Ampullae Reproductive structures found in hydrozoan coral.
Anterior The head or leading end of an animal. The term is also used to denote position. Thus, the head of an arthropod is anterior to its thorax.
Anthozoa A class of marine coelenterates (phylum Cnidaria), such as sea anemones and corals. Anthozans are animals with radial symmetry. The dominant form is the polyp, which can be large and quite complex. Most, but not all, anthozoans are colonial.
Antipatharian coral Coral that produces a hard proteinaceous skeleton; Black coral.
Appressed Corallite Radial corallites of Acropora with one side fused to the branch axis.
Arborescent Coral with a tree-like growth form.
Archipelago A group of islands. An archipelago may consist of isolated volcanic seamounts or mountain tops whose lower slopes and valleys have been submerged.
Askeletal corals and larvae Corals and larvae that do not have skeletons.
Atoll A ring of land surrounding a tropical lagoon, and which is in turn surrounded by a coral reef. An atoll is frequently formed of basaltic rock of volcanic origin and is capped with limestone covered with coral. The islets that form atolls range in size from those less than a mile (1 km) in diameter to those over 78 miles (120 km) in diameter.
Axial Referring to the corallite formed at the tip of a branch.
Axial Corallites Distinctive corallites at the apex of Acropora branches, usually much larger than Radial corallites below.
Azooxanthellae Cnidarians without symbiotic photosynthesizing algae. Species described as azooxanthellae commonly feed on passing plankton and waterborne material.
Barrier reef A partially submerged coral outcrop on the seaward side of a lagoon. The barrier reef follows the contour of the land, of which it may be an extension. Water in the lagoon is shallow, permitting coral growth, but the descent is steep on the ocean side. Barrier reefs result from coral growth or a change in the level of the seawater or subsidence of the beach area.
Bleaching Condition when colored zooxanthellae are expelled from a living coral due to stress, resulting in a weakened specimen with its white skeleton clearly visible through the animal's transparent tissue.
Bottlebrush Acropora growth form where branches are lined with many elongate tubular corallites.
Budding Process of corallite reproduction by division to create identical copies
Caespitose Bushy growth form of Acropora with branches dividing with 3 axes.
Calyx Portion of corallite defined by the outer wall, plural calices.
Calice The upper surface of a corallite to which the soft parts of an individual polyp are attached i.e. the upper, open end of the corallite.
Cerioid Massive corals that have corallites sharing common walls (e.g. the upper surface of the corallum).
Cnidaria A phylum whose members have tentacles, nematocysts, and radial symmetry. They are, for the most part, marine
Coenosarc An extension of the polyp that stretches over the surface of the skeleton.
Coenosteum Thin horizontal skeletal plates between corallites.
A group of marine animals belonging to the phylum cnidaria, that exist as small sea anemone-like polyps, typically in colonies of many identical individuals; or the skeletal remains of coral polyps.
Coral reef Aragonite (calcium carbonate) structure produced by corals and found in shallow, tropical marine waters.
Colline Elongate wall or ridge formed between corallites or groups of corallites. Columella a skeletal structure that develops in the central axis of the calice. It is usually either styliform (rod-like), papillose, trabecular (both spongy in appearance) or lamellar (formed from a series of interconnecting vertical plates).
Columella Skeletal structure at center of corallite; none, porous, peg, or rod-like.
Colonial Corals composed of many individuals a group of polyps formed from a common parent by budding. There is no clear distinction (e.g. in fungiids) between single individuals with many mouths and colonies of individuals with single mouths.
Colony Coral composed of multiple corallites; compare to Solitary.
Coral and coral reefs Cnidarians of the class Anthozoa; they are polyps, predominantly with sixfold or eightfold symmetry, and are either solitary or colonial. The coralline coelenterates construct calcium containing shells of characteristic shapes. Colonies of coral and their associated foraminifera and symbiotic algae live best in tropical and semitropical environments.
Corallite The skeleton of an individual coral polyp / the skeletal parts deposited by a single polyp.
Corymbose Acropora growth form where plates or clumps are composed of interlocking horizontal branches with upturned tips.
Digitate Growth form of short thick vertical branches that are finger-like.
Costae Extension of the septa outside the corallite wall.
Dendroid Corallum formed from spreading branches of single corallites.
Dissepiments Skeletal structures left by the polyps.
Edge zone A horizontal fold of the polyp wall that extends over the corallite wall.
Encrusting Relatively thin growth form which closely approximates the surface beneath.
Endemic Species restricted to a specific area.
Extratentacular budding Process of budding that grows outward from the parent corallite's outer wall; compare to Intratentacular budding.
Explanate Colony spreads out flat, plate-like or foliaceous.
Exsert A term used to describe septa that protrude above the top of the corallite wall.
Flabellate Colony in which the meanders arise from a common base but are free laterally. They may be relatively short (crescentic) or elongate and sinuous (flabello-meandroid).
Flabello-meandroid Corals with polyp-containing valleys that are separated by additional ridges.
Fossa The central depression in a calice, usually partly filled by the columella.
Free-living Corals that are not attached to the substrate.
Fringing reef A reef attached to an island or a continent. The seaward side may be submerged and therefore a navigational hazard.
Great Barrier Reef A coral reef that lies east of Australia, stretching from the Torres Strait south of New Guinea (Irian) to the Tropic of Capricorn. It is more than 1,750 km (1,100 miles) long and the world’s largest reef.
Hermatypic Corals that contain endosymboionts and contribute to the building of reefs. 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 former two are ambiguous and the latter is restricted to extant corals and other taxa with zooxanthellae
Hydrozoa A class of cnidarians that characteristically exhibits alternations of generations, often with a sessile polyp giving rise to a pelagic medusoid form by asexual budding.
Immersed / Inserted A term used to describe septa which do not protrude above the top of the corallite wall.
Immersed corallites Corallites with opening embedded within coenosteum.
Incipient Axial corallites in some species of Acropora that are smaller than average.
Intratentacular budding Process of budding that occurs within the parent corallite's outer wall; compare to Extratentacular budding.
Imperforate Referring to skeletal structures in corals (e.g., walls, septa, coenosteum) that are solid rather than porous.
Indicator species One or more organisms used to assess the ecological health of a biome.
Keystone species A predator at the top of a food web, capable of consuming organisms of more than one tropic level beneath it and strongly affecting the community structure.
Massive Thick colonies, often having a round, dome, or cube shape.
Meandroid Massive corals that have corallite mouths aligned in valleys such that there are no individual polyps; i.e. in which the corallites are fused in longitudinal series to produce a pattern of valleys and ridges.
Mesenteries/mesenterial filaments The mesenteriesare radial partitions lying within the gastrovascular cavity of the coral polyp; mesenterial filaments may be produced from their free inner margins; coiled tubular structures within the polyp body cavity.
Monticule Conical process arising from corallite walls that include ribs, also known as Hydnophore.
Nariform Triangular radial corallites of Acropora resembling an upside-down nose.
Oral disc Upper surface of the polyp, extending from the mouth to the outer ring of tentacles.
Pali Vertical rods (pali) or plates (paliform lobes) arising from inner end of septal plates.
Papillae Warts, rods, or lumps on coenosteum which are no larger than a corallite.
Parasite An organism that feeds on the tissues of another organism. Parasites are one of the major causes of disease in aquarium fishes.
Petaloid septa Primary septa with a petal-like appearance surrounded by smaller septa; Family Siderastreidae.
Paliform lobe A vertical lobe-like protrusion formed at the inner end of a septum, adjacent to the columella.
Perforate Referring to skeletal structures in corals (e.g., walls, septa, coenosteum) that are porous rather than solid.
Peristome Area within the inner ring of tentacles and immediately surrounding the mouth.
Peritheca The surface of the coenosteum between the corallites.
Phaceloid Corals that have corallites adjoined only towards their base; i.e. in which tall, separate corallites arise from the basal part of the corallum.
Plocoid Massive corals that have corallites with separate walls (c.f. cerioid corals) i.e. in which corallites are separate and well defined.
Planula Free-swimming coral larvae.
Plocoid Colony with elevated corallites that do not share walls.
Polyp Typically sedentary soft-bodied component of Cnidaria (corals, sea pens etc), which comprises a trunk that is fixed at the base; the mouth is placed at the opposite end of the trunk, and is surrounded by tentacles.
Prostrate Branching coral that grows horizontally just above the substrate.
Radial corallites Smaller corallites that occur on side of Acropora branches; compare to Axial corallites.
Rasp-like corallites Long radial corallites in Acropora with curved, knife or rasp-shaped openings.
Satellite colonies Colonies that develop within the tissue of parent colonies and which have their own unattached skeletons. Best seen in Goniopora stokesi.
Scleractinians Corals which have a hard limestone skeleton and belong to the order Scleractinia.
Scale-like corallites Short radial corallites in Acropora with curved, fish-scale like appearance.
Septa Radiating skeletal plates or ribs within a corallite's walls, may be in several cycles by size.
Septo-costae Radiating skeletal plates or ribs that are continuous, extending outside the corallite walls onto the coenosteum and usually shared with adjacent corallites; Family Agariciidae, Siderastreidae.
Septal cycles Relating to the formation and arrangement of the septa. Septa are laid down in radial series or cycles, the first cycle consisting of six primary septa, the second of six secondary septa, the third of 12 tertiary septa, and so on, Septal margin the upper free edge of the septum
Septal orders Relating to the size of septa. Equal sized septa form a single order; subequal or unequal septa form two or more orders. Orders do not necessarily correspond to cycles
Septocostae Extensions of the septa that unite adjacent calice centers. They are found in corals where the corallites lack walls and there is no clear distinction between septa and costae.
Septum The calcareous, plate-like structures that radiate from the wall toward the center of the corallite. They are aligned vertically and alternate with the mesenteries.
Solitary Referring to corals that grow as a single polyp with a surrounding skeleton.
Synapticulae Small bars that make lateral links between adjacent septa.
Thamnasterioid A corallum in which corallite walls are indistinct and the septa run uninterrupted between calice centers.
Trochoid Colony top shaped.
Turbinate Colonys haped like an inverted cone.
Vernacular name A name proposed in a language used for general purposes as opposed to a name proposed only for zoological nomenclature. In the Catalog one finds the expression, "Not available, appeared as a French vernacular.
Zoanthidea Colonial polyps that resemble sea anemones. They are anthozoans of the phylum Cnidaria and are related to the corals. They inhabit sandy bottoms in tropical to temperate water, an ecological niche similar to that of the sponges.
Zooxanthellae A group of symbiotic dinoflagellates living endosymbiotically in association with one of a variety of invertebrate groups (e.g., corals). In corals, they provide carbohydrates through photosynthesis, which are used as one source of energy for the coral polyps. They also provide coloration for the corals.