Stylephoridae
by R. K. Johnson and L. U. Berman
Elongate, slender, extremely compressed and ribbon-like, lacking scales. Head large; eyes directed rostrad, large, tubular; snout short, mouth small, tubular, highly protrusible. Maxillary with a partly biserial row of small teeth; premaxillary edentate. Gillrakers 7-9, rather short, spikelike. Dorsal fin extending from occiput to just before caudal fin; analfin base short, its origin just before middle of standard length; pectoral fin base horizontal; pelvic fin with one short ray just behind pectoral fin base; caudal fin in two distinct portions: 6 or 7 upper rays directed upward, 2 lower rays stout and extremely elongate, reaching or exceeding twice the SL. Swimbladder absent. Stomach divided into two chambers. Larvae unknown; small juveniles with eyes semitubular and directed dorsolaterad, first two dorsal finrays distinctly elongate, upper caudal finrays directed posteriad.
Mesopelagic, probably vertical migrations each day-night cycle; not an active swimmer but 'hovers'. Feeding primarily (or exclusively) on copepods; adapted for 'pipette' feeding; rapid jaw protrusion and very large suction velocity should allow effective capture of prey at distances up to 50% of its head length, the enormously prolonged caudal fin acting as a 'sea anchor', a stabilizing device. Reproduction unknown.
Genera 1.
Recent revisions: Pietsch (1978—feeding mechanism); Munk (1966 ocular anatomy).