Author: Hermann, 1781
Sternoptyx diaphana Hermann, 1781
Status in World Register of Marine Species:
Accepted name: Sternoptyx diaphana Hermann, 1781 (updated 2009-06-25)
Diagnosis: body laterally compressed, deep; eye directed laterally; mouth vertical; gillrakers on first arch (6) 7 (8); branchiostegal rays 6, 3 on epihyal. Dorsal finrays 9-11 followed by a dorsal adipose fin; dorsal blade of single spine with anterior serrated projection; pectoral finrays 10-11, anal finrays 13-15; anterior anal pterygiophore elongate, bearing external spine and supporting triangular membrane above anal fin; posterior anal pterygiophores short and extending little posterior to AC1, (more so in sub-adults); little extension of ventral body margin posterior to AC1 in adults, more so in sub-adults; post-temporal spines poorly developed; post-abdominal spines (iliac) well developed, abdominal keel well defined. Vertebrae 29-30. Photophores (adult): ORB 1, unpigmented, ventral to eye which has ventral aphakic gap; BR (3); OP 3; IP (S); PV (10); VAV (3) (pre-anal); AC (3) + (4) (anal + sub-caudal); OA (3) + 1 (supra-pectoral + supra-anal), supra-anal photophore low on body, close to AC, in sub-adults (under about 17 mm SL), its height usually more than 3.2 times in trunk depth; AC1, group large, longer than least caudal peduncle depth and about 10% SL or more in adults, smaller in sub-adults. Colour: back dark, flanks silvery, little or no caudal finray pigmentation. Size: to 46 mm SL.
Habitat: oceanic, deep mesopelagic at 300-1,100 m; non-vertical migrant. Food: random, possibly a cyclic feeder: small crustaceans (copepods, ostracods, euphausiids, amphipods, etc.), fishes and other taxa. Reproduction: dioecious; adult photophore complement acquired at 11-13 mm SL.
Distribution: common temperate - subtropical - tropical in Atlantic, 45° N-30° S; northernmost captures 51-52° N, off Eire and 45° W; probably absent in Mediterranean but 'Sternoptyx diaphana . . . reported from the eastern Mediterranean (Lebanon) by George et al. (1964), simply quoting . . . without details.' (Tortonese and Hureau, 1979).
Eggs, larvae and young stages. Brauer, 1906: 119, fig. 59-63 | Haedrich and Nielsen, 1966: 909 | Bright and Pequegnat, 1969: 34.
Otoliths (sagitta). No data.