The arrangement, type, and number of the teeth in a particular species

To remove oxygen from.

Reduction in breeding population size leading to reduced fecundity in the overall population or stock of a species.

Vertically or dorsoventrally flattened.

Used in phylogenetics in reference to a character or character state not present in the ancestral form of a species; apomorphic.

See derived trait.

See derived trait.

In phylogenetics, a trait present in an organism which was absent in the last common ancestor of the group being considered; an apomorphy. Also used to refer to traits present in the ancestral form that have subsequently been lost.

Of or relating to skin.

Bone-type ossifying directly from connective tissue membranes and thus lacking a cartilaginous predecessor. Tend to be more numerous in primitive fish forms.

See placoid scale.

Innermost layer of skin containing nerve endings and blood vessels. Lies under the epidermis and also known as corium.

Used in ichthyology in reference to a written description of a new species, usually in the form of a scientifically-published paper though many have been also appeared in aquarium literature, particularly in the late twentieth century. Also referred to as ‘type description’ or ‘original description’.

In icthyology, the nomenclatural act by which the type specimen of a previously or newly-established genus, subgenus, species, or subspecies is fixed via an express statement.

Dry; completely dried out.

In biology, organic debris most often formed via the decomposition of organisms.

A fish that migrates between fresh and salt waters.

Period of suspended development in an organism characterised by greatly reduced metabolic rate; resting phase. Especially common under times of environmental stress, e.g., hibernation, aestivation.

Delicate, translucent.

Large group of algae often referred to as 'brown algae' in relation to aquaria. Most are unicellular but there also exist colonial types. Very common component of phytoplankton.