The
hooked squid,
family Onychoteuthidae, currently comprise approximately 20–25 species (several known from only single life stages and thus unconfirmed), 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.