Maurolicus Cocco, 1838
Diagnosis: body fusiform; mouth moderate, subvertical; pseudobranch present; gillrakers on first arch 22-31 (geographical variation). Meristic data (for eastern North Atlantic and Mediterranean only): gillrakers 20-24 + 6-7 = 27-31; branchiostegal rays 10, 3 on epihyal. Dorsal finrays 11 (9-12); pectoral finrays 17-19; pelvic finrays 7; anal finrays 22-28; dorsal origin in advance of anal fin origin; anus near anal fin origin; dorsal adipose fin present. Vertebrae 33-35. Swimbladder well developed, gas-filled, euphysoclistous. Scales deciduous. Photophores (adult): ORB l; OP 3, OP3 single; BR (6); IP (6); VAV (6); AC in 3 groups as 2 long groups preceded by a single, elevated photophore: I + (14-17) + (89) = 23-27; PV (12-13); OA (2) + 5; SO present. Colour: body silver with dark back bearing light brown dorso-lateral undulating strip and a pigment extension ventrally at procurrent rays; anterior two dorsal rays, dorsalmost pectoral ray and outer 2 or 3 caudal rays pigmented; snout and jawbones transparent with characteristic pigment spots. Size: to 65 mm SL.
Habitat: mesopelagic, at 10-400 m (adults below 200 m) by day, with some dusk migration into upper 100 m; migrate at night into upper 100 m; in subpolar-temperate Atlantic, egg vertical distributions imply seasonal vertical displacements of mature adults, these residing deeper in summer; not so in Mediterranean. Food: selective, a cyclic feeder on copepods and euphausiids; copepods predominate food of young. Reproduction: spawning spring-summer north of 40° N, year round in Mediterranean, occurs at depth in daytime; 200-500 sculptured eggs/ ovary pair, about 1.3-2.0 mm diameter, rising to surface layers; postlarvae sink gradually with development; photophores develop over 5.5-23 mm SL, some of BR being the first to appear.
Distribution: in area northward to 70° N, off Norway and in fjords, and Iceland, extending south to Gulf of Cadiz; extends southwards along north-western African slope; in Mediterranean abundant western basin, especlally Alboran Sea, uncommon eastern basin; Isolated population, Sea of Marmara.
Species 1 considered valid.