abdominal--on the belly

adipose fin--flap without rays, on back between dorsal and caudal

anal fin--median fin between anus and caudal fin

anterior--in the front

barbels--sensory projections around mouth

caudal peduncle length--from the base of the last anal ray to the caudal base

caudal peduncle depth--minimum vertical depth between anal and caudal fins

depth of body--greatest distance from back to underbelly

dorsal fin--median fin on back, with rays and sometimes spines

fin membrane--web of skin between fin rays

fin ray--segmented and branched fin supports, counted from the first long ray (as #1) to the last one, branched to its base ganoid--hard enameloid scale

gill rakers--anterior projections on gill arches for food capture

gular plate--large median bone on the throat

lateral line--row of scales along the sides, with sensory pores

maxilla or maxillary--upper jaw bone

oblique--mouth slanted

opercle--gill flap or (especially) largest gill-covering bone

pelvic fin--paired fins on the abdomen or chest

pharyngeal arch--5th gill arch, under gill cover, with teeth

preopercle spines--posterior and ventral spines on back of cheek

principle ray--fin ray that extends to outer edge of fin

ray--fin support made of bony segments (see fin ray)

rhomboid scale--diamond shaped scale


spine--fin support that is not segmented, often sharp, never branched, but sometimes flexible (e.g in sculpins)

subterminal mouth--mouth position below end of face

terminal mouth--positioned at the center of the end of the face

thoracic--on the chest, as in percoid pelvic fins

tubercles--sharp, horn-like projections on the fins or head