Argyropelecus affinis

Author: Garman, 1899

Argyropelecus affinis Garman, 1899

Status in World Register of Marine Species:
Accepted name: Argyropelecus affinis Garman, 1899 (updated 2009-06-25)

Diagnosis: body laterally compressed, profile ventral to dorsal blade smooth and not raised markedly posterior to blade, snout profile smooth; eye tubular, directed dorsally; mouth vertical; gillrakers on first arch 1820, branchiostegal rays 10, 3 on epihyal. Dorsal finrays 9, followed by a dorsal adipose fin; dorsal blade low, its height less than one-third its length; pectoral finrays (10) 11-12; pelvic finrays 6; anal finrays 13. Postorbital spine absent; upper preopercular spine short, not extending posterior to opercle, leading laterally and hooked anteriorly (adults) or straight and directed latero-posteriorly (juveniles under about 22 mm SL); lower spine long, curved anteriorly (adults) or straight (under about 30 mm SL); posterior edge of exposed part of anterior cleithral notch with (3) 4-7 weak serrations; post-abdominal spines short, equal; ventral keel shallow, extending little beyond PV photophore. Vertebrae (38) 39 (40). Swimbladder well developed, gas-filled, euphysoclistous. Scales deciduous. Photophores: configuration of compound light organs changes in some groups after adult complement is acquired: initial configuration, BR (6); IP (6); PV (4) + (2) + (2) + (4); VAV (2) + (2); AC, (1) + (3) + (2); AC2 (1) + (3). Colour: back dark, flanks silvery. Size: to 72 mm SL.

Habitat: oceanic, mesopelagic at 300-600 m (sometimes shallower); nonmigrant or makes short diel migrations. Food: in smaller animals, copepods and ostracods, tending to euphausiids, salps, chaetognaths in larger ones. Reproduction: dioecious; adult complement of photophores acquired at about 14 mm SL.

Distribution: circumglobal, subtropical- tropical; rare in area: 'occasional captures between Azores and Madeira' (Baird, 1971); absent in Mediterranean (but see Tortonese and Hureau, 1979).

Eggs, larvae and young stages. Brauer, 1906: 103, fig. 44.
Otoliths (sagitta). No data.