Glossary

operculum

Flap composed of 4 bones that covers, supports and protects the gill opening in many fishes. Also known as gill flap or gill cover.

Used in 64 species profiles

gill
Respiratory organ of fishes and some other aquatic organisms comprising a highly-vascularised membrane or outgrowth.
gill opening
Opening connecting the gill chamber to the exterior environment. Also referred to as the gill slit.
head length
Normally a straight-line measurement taken from the tip of the upper lip to the posterior edge of the operculum.
interopercle
One of the bones comprising the operculum.
opercle
Bone forming the upper, posterior portion of the operculum, sometimes bearing spines or spine-like structures. Normally the largest of the bones comprising the operculum.
opercular
Of or related to the operculum.
pseudobranch
Accessory or spurious gill, often located on the inner surface of the operculum in various fishes, that is usually small and sometimes completely obscured beneath the epithelium. Also referred to as pseudobranchia.
subopercle
One of the bones comprising the operculum, situated below the opercle.