Filamentous extensions of the caudal fin tips seen in some fishes.

A fleshy, raised ridge extending along the caudal peduncle, most commonly the dorsal surface.

The typically narrow section of the body located between the posterior of the dorsal and anal fins and caudal fin origin. Its depth is measured vertically at the narrowest point.

Count often used in species descriptions and comparisons, made by counting the number of scales present around the narrowest part of the caudal peduncle.

Also referred to as the tail fin, it's main purpose is thrust and propulsion.

See 'cavity brooder'.

Reproductive strategy characteristic of certain fishes, e.g., many cichlids, in which eggs in a cavity, cave or similar. The clutch is normally guarded aggressively by one or both parents. Such species may also be referred to as 'cave brooders/breeders'.

Abbreviation for cubic centimetre/centimeter (UK/US).

Temporary organ normally located on the head in fry of some fish species. Excretes an adhesive substance and used to attach to solid surfaces.

A water-filled limestone sinkhole. The term is normally used to refer to such features located specifically in the Yucatán Peninsula, southeastern Mexico.

Current and most recent of the three Phanerozoic geological eras, immediately following the Mesozoic Era and covering the period from 65.5 mya to the present. Also known as the ‘Age of Mammals’ due to the great diversification occurring among that group, it’s divided into three periods: Paleogene, Neogene, and Quaternary; and seven epochs: Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, and Holocene.

The solid central part of a vertebra, not including the bases of the neural arch.

Of, relating to or located on, in or near the head.

Any marine mollusc of the class Cephalopoda which includes octopus, squid, cuttlefish, and nautilus. Characterised by possession of a large head and eyes, prehensile tentacles, and, in most species, a specialised sac containing a dark, inky fluid used in defensive behaviour.

Longest bones or cartilages of the branchial arches, located beneath the epibranchials.

Abbreviation of the word ‘confer’, meaning ‘compare with’. Used in the fields of systematics and taxonomy to denote specimens or populations that resemble a described taxon but differ in some respects and thus may or may not represent a distinct species.

In ichthyology, any characteristic or its attributes used for recognising, describing, defining, or differentiating species, genera or higher taxa. Also used in phylogenetic analyses whereby ancestral (primitive) characters are termed plesiomorphic and derived (novel) characters apomorphic.

List of species, sometimes annotated.

An unpublished scientific name, also known as 'manuscript name'.

A type specimen of a species that only appears in an unpublished source.