Author: Schultz, 1961
Polyipnus polli Schultz, 1961
Diagnosis: body laterally compressed, deep; eye directed laterally; mouth vertical; gillrakers on first arch 21-23; branchiostegal rays 10. Dorsal finrays 14-15 (16); dorsal blade small, derived from fusion of anterior radial with seventh supraneural, followed by a dorsal adipose fin; pectoral finrays (12)13-14; pelvic finrays 7; anal finrays (15)16-17; posteriormost dorsal and anal finrays split to base. Post-temporal spine short without basal spines; post-abdominal (iliac) spines conspicuous, directed posteroventrally; abdominal keel scales smooth; anal anterior pterygiophore spine well developed; curvature of body margin ventral to ACI enhanced by extension of anal pterygiophore. Vertebrae 32-34. Swimbladder well developed, gas-filled, euphysoclistous. Scales deciduous. Photophores: ORB I pigmented, directed into eye, OP 3; BR (6), IP (6); PV (10); VAV (S); AC2 (4); ACI photophores (7-8), the anterior 3 on slightly lower level to posterior ones; OA (2) + 1 (= supra-pectoral) + 3 (= supraabdominal) + 1 (= lateral) + 1 + (2) (= supra-anal). Supra-anal photophores vertically well separated from AC1 with anterior one lower than posterior pair; anterior supra-abdominal photophore higher than posterior supra-abdominal photophores. Colour: back dark, flanks silver; dark pre-dorsal pigment bar extending towards, but not reaching, midline. Size: to about 50 mm SL.
Habitat: pseudoceanic, mesopelagic at 100-400 m, post-larvae shallowest, adults deepest; non-migrant. Food: unknown. Reproduction: dioecious; adult photophore complement acquired at about 20 mm SL.
Distribution: common, endemic tropical eastern Atlantic, about 20° N-10° S, rare west of 25° W; single record in area, Grand Meteor Bank (30° 55' N, 24° 19' W) (Kotthaus, 1972).