gibell Aquarium Society

Family STERNOPTYCHIDAE 180marine hatchetfishes Marine Atlantic Indian and Pacific

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Six to 10 branchiostegal rays, three on epihyal (= posterior ceratohyal); 3-7 (usually six) branchiostegal photophores; pseudobranch present (reduced or lost in most other stomiiforms). Ten genera and about 67 species.

Subfamily Maurolicinae. Body elongate, never extremely compressed; adipose fin present or absent; 19-38 anal fin rays; photophores present on isthmus, six on branchiostegal membrane. This taxon is probably paraphyletic (Harold and Weitzman, 1996).

Seven genera, Araiophos, Argyripnus, Danaphos, Maurolicus, Sonoda, Thorophos (synonym Neophos), and Valenciennellus, with about 25 species (e.g., Parin and Kobyliansky, 1996; Harold and Lancaster, 2003; Harold, 2003).

Subfamily Sternoptychinae (marine hatchetfishes). Body deep and extremely compressed; mouth nearly vertical; preopercular spine; eyes sometimes telescopic; abdominal keel-like structure; blade in front of the dorsal fin composed of specialized dorsal pterygiophores; anal fin sometimes divided, rays 11-19; dorsal fin rays 8-17; vertically orientated pelvic bones; adipose fin rarely absent (e.g., in Polyipnus latirastrus).

Three genera, Argyropelecus (seven species, broadly worldwide, high-sea pelagic, usually 100-600 m), Sternoptyx (four species, broadly worldwide, high-sea pelagic, 500-1,500 m), and Polyipnus (31 species, usually coastal, 50-400 m; most species in the western Pacific), with 42 species (e.g., Harold, 1994, 2003).

Suborder Phosichthyoidei. Three bony pectoral fin radials (rarely 0-2 in some genera with reduced pectoral fins); branchiostegal rays 10 (Bathophilus) to 28 (Heterophotus).