Boreal Clubhook Squid

Onychoteuthis borealijaponica Okada, 1927

DIAGNOSIS.—Mantle muscular but rather thin. Fins rhomboidal, length 55%–60% ML, width 65%–75% ML, apical angle 80°–90°. Nuchal folds 8 or 9 pairs. Arm formula II = III = IV > I, length 35%–45% ML. Tentacle club slightly expanded, length 20%–30% ML, 13–15 small suckers on dactylus, 25–27 hooks on manus in 2 rows, well-defined fixing apparatus with 8–10 suckers and 7–9 pads. Large luminous patch on ventral periphery of each eye. Two oval light organs in ventral mantle cavity, 1 on ink duct behind anal papilla, 1 on ink sac, with intervening silver, iridescent band; former much smaller than latter. Large species maturing at about 250 mm ML in males and about 300–350 mm ML in females.

ORIGINAL DESCRIPTION.—Okada, 1927:4.

TYPE LOCALITY.—Japan.

DEPOSITION OF TYPE.—Holotype: Not known.

Paratypes: None.

DISTRIBUTION.—Far northern Pacific, migrating from south to subarctic waters for feeding during summer and returning to subtropical waters for spawning in fall and winter (Naito et al., 1977; Kubodera et al., 1983; Murata et al., 1986).