The hooked squid, family Onychoteuthidae, currently comprise about 20–25 species, in six or seven genera. They range in mature mantle length from 7 cm to a suggested length of 2 m for the largest member, Onykia robusta. The family is characterised by the presence of hooks only on the tentacular clubs, a simple, straight, funnel–mantle locking apparatus, and a 'step' inside the jaw angle of the lower beak. With the exception of the Arctic Ocean, the family is found worldwide.
Hooked squid
Reaching a mantle length of 2 m, Onykia robusta is the largest onychoteuthid and one of the largest of all squid.
A nearly mature female of the undescribed species Onykia sp. A (27.2 cm ML), taken from the stomach of a swordfish
Onykia robusta, also known as the robust clubhook squid and often cited by the older name Moroteuthis robusta, is a species of squid in the family Onychoteuthidae. Reaching a mantle length of 2 m (6.6 ft), it is the largest member of its family and one of the largest of all cephalopods. The tentacular clubs are slender, containing 15–18 club hooks. Arms of the species contain 50–60 suckers, and grow to 90–100% of the mantle length. It is found primarily in the boreal to Temperate Northern Pacific.
Onykia robusta
Kubota's photograph of a large O. robusta, which was misidentified as the giant squid, Architeuthis dux