Touching but not physically joined; sharing a common boundary.

The tendency of unrelated animals and plants to evolve superficially comparable characteristics under similar environmental conditions.

Independant acquisition of the same biological trait in unrelated, monophyletic, lineages as a result of inhabiting similar environments or ecological niches.

Arched; curved outwards. Oppsite of concave.

Any member of the subclass Copepoda, a group of small marine and freshwater crustaceans of which the planktonic species are important to global ecology, forming the main constituent of oceanic zooplankton. Some species are parasites of fishes.

Refers to bodies of water containing high levels of nutrients. Opposite of oligotrophic.

Feeding on excrement, a behavioural adaptation seen in numerous fishes.

Paired endochondral bone located at the base of the pectoral fin upon which rest the pterygials or actinosts. Attaches to the cleithrum anteriorly.

Any marine animal of the class Anthozoa, these being characterised by possessing a horny or calcareous skeleton, aggregations of which form coral reefs and islands.

Erosion-resistant aquatic structure formed from living corals, their rock-like skeletal secretions and calcium carbonate deposits from other organisms such as calcareous algae, molluscs, and protozoans.

Sand originating from marine environments via bioerosion of the calcareous skeletal structures possessed by some organisms. Coral is not the chief constituent, however, with the majority of material deriving from foraminifera, calcareous algae, molluscs, and crustaceans.

Any red algae of the order Corallinales, characterised by possession of a hard thallus containing calcareous deposits. Often pink, purple or red in colour.

A corrective note published in order to cite errors from an earlier work alongside their corrections.

Steroid hormone released by the cortex (outer portion) of the adrenal gland as a response to stress.

See costiasis.

Disease of freshwater fishes caused by species of parasitic flagellate protozoa from the genus Ichthyobodo and more accurately referred to as ichthyobodiosis. It attacks the gills, fins and skin with symptoms including an increase body mucus secretion giving rise to the vernacular term ‘skin slime disease’. Can be treated using proprietary products but frequently fatal otherwise.

See Saprolegnia.

Term formerly used in zoological taxonomy and equivalent to the modern terms syntype and paratype but no longer valid according to the ICZN code.

Form of camouflage in which an organism possesses darker pigmentation on the parts of the body exposed to light and paler on those normally shaded. Many fishes are coloured darker dorsally and lighter ventrally for this purpose.

A pair of descriptive statements. Often used in species identification keys to offer the reader a choice resulting in identification of a species or continuation to the next couplet.