Photichthyidae
(including Gonostomatidae Witzell, 1973 (part))
by J. Badcock
Deepwater fishes, usually small, some (Polymetme) medium-sized; body more or less elongate; premaxillary teeth uni- or biserial; dentary teeth biserial anteriorly; gillrakers well developed; branchiostegal rays 10-21, 4-7 on epihyal; dorsal adipose fin present (except Yarella); 3 pectoral radials.
Photophores: discrete, not sharing photogenic masses; BR photophores (7) 8-18; isthmus with photophores; ORB t-2.
Generally oceanic, some pseudoceanic, some benthopelagic; juveniles and adults at about 200-800 m by day; pre-metamorphic post-larvae near surface. Some are diel vertical migrants, other partial or non-migrants; post-larvae sink rapidly at metamorphosis to adult diurnal depth levels. Feeding on zooplankton. Dioecious. Metamorphosis accompanied by marked body shrinkage, with most ventral photophores developing simultaneously.
Genera 7; in Clofnam area 4.