View data on Catalog of Fishes here.
Dorsal-fin rays 8; anal-fin rays 11; pectoral-fin rays 10–11; total gill rakers (rarely 18) 19–23 (rarely 24); vertebrae (rarely 36) 37–38. Dwarf species rarely exceeding 38 mm SL; trunk very long and narrow; its depth at origin of anal photophores three or more times into greatest body depth, subcaudal photophores well separated from anals; dorsal spine medium-to-high, its height often exceeds its length; post-temporal spines well developed; postabdominal spines fused to form a single spine complex; lower preopercle spine directed ventrally, the upper posterio-dorsally; jaws medium; teeth small to minute; gill rakers long and numerous; in preservative abdominal region dark, trunk pigmentless except in definite patches along midline and above anal and subcaudal photophore groups.
Two pigment forms designated form "A" and form "B" occur over much of the species range. Form A is characterized by distinct and clearly defined body pigmentation, while in form B, the body pigmentation is quite diffuse. This pigment difference is not a function of size or sex, is intermediate in few individuals, and both forms do occur syntopically. A morphometric analysis of three sympatric populations in several characters and meristics, plus measurements from one or the other pigment forms from other areas by Baird (1971) failed to show any significant difference between sympatric populations. In addition, there was no consistent sorting out over the range of variability of any one form in any character. Analysis of diurnal depth distributions revealed a marked sorting out of pigment types with the A form most numerous during the day while the B form was predominantly caught at night.
Differs from all other species in genus Argyropelecus by its narrow trunk, single postabdominal spine, small size, minute teeth, presence of only eight dorsal and eleven anal rays.
Occurs in the South Atlantic around the Falkland Islands and abundantly off the southeast coast of Brazil; a scattering of catches along latitude 35° S to the Cape of Good Hope suggests a broad distribution across the South Atlantic; occurs in small catches along the southwest African coast, appears absent in the Gulf of Guinea, but occurs in the western tropical Atlantic; is taken in moderate numbers in the Caribbean and Gulf of Mexico and abundantly in the western Atlantic; is abundant across the North Atlantic and the eastern North Atlantic as far south as the Cape Verdes Islands; it represents the only species of this family in the Mediterranean, where it occurs abundantly in the western basin; scattered moderate-to-small catches are present from to 12°S latitude in the central Indian Ocean, and another population is scattered from 20° S to 40° S with several small catches reported from the southeastern and southwestern Indian Ocean; a single catch off the Philippines, another at 42°N, I69°E, and small catches from the Banda Sea and near Hawaii represent this species in the west and central Pacific; large populations occur off California and Chile; it is taken abundantly across the Southern Ocean from 35°– 55°S latitude from Chile to New Zealand; taken in small numbers in the Tasman Sea and off Sidney, Australia.
Occurs from 200 m to 700 m by day with the greatest concentration between 350– 550 m; occurs from 100 m to 650 m by night with concentrations between 150–380 m; tropical submergence indicated in the Gulf and Caribbean by examining number of catches above 200 m compared with the North Atlantic; by day it appears to concentrate at about 550 m in the Sargasso Sea.
Baird RC. 1971. The Systematics, Distribution, and Zoogeography of the Marine Hatchetfishes (family Sternoptychidae). Bulletin of the Museum of Comparative Zooology 142(1):1–128.
Baird RC. 1971. The Systematics, Distribution, and Zoogeography of the Marine Hatchetfishes (family Sternoptychidae). Bulletin of the Museum of Comparative Zooology 142(1):1–128.
Rarely exceeds about 40 mm SL.
Messina, Sicily, Italy, Mediterranean Sea.
No types known.