See head and lateral line erosion. Often abbreviated to HITH.

The single specimen designated as the name-bearing type of a nominal species or subspecies.

The ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physiological processes.

Exhibiting a a degree of similarity, e.g., in anatomical position, structure, function , or character that may suggest a shared ancestral or evolutionary origin.

Two or more names of identical spelling, or differing only in suffix, that have been applied to different members of the same taxonomic rank and of which only one can be valid at any given time.

A character or trait shared by two or more unrelated taxa. Typically the result of convergent or parallel evolution.

Hard and rough in texture.

See quarantine tank.

Of, relating to, or situated on the humerus.

Bony process extending posteriorly from the pectoral girdle, above the base of the pectoral fin. Present only in certain fishes.

A marking on the body in the area analogous to the humerus, or shoulder. In fishes it’s normally located above the pectoral-fin and behind the opercle. There may be more than a single such spot in some species.

The pectoral girdle in most fishes.

Agricultural cultivation or production of plants or livestock, especially domesticated varieties.

Glassy; translucent; transparent.

Organism resulting from a natural or artificial cross between genetically-unlike individuals.

The process of crossing different species or populations of organisms in order to produce hybrids.

The scientific study of water, its distribution, properties and effects on and within the Earth's surface and atmosphere.

Instrument used to measure the density of a liquid, normally in the form of specific gravity. Can be inaccurate should calcium deposits form on the swing arm, for example, and generally less reliable than a refractometer.

Having an affinity for water.

Lacking an affinity for water.