Funnel–mantle locking apparatus of a juvenile male Argonauta hians

The funnel–mantle locking apparatus is a structure found in many cephalopods that connects the mantle and hyponome (funnel) and restricts their movement relative to each other. It consists of two interlocking components: one located on the mantle (often fibrous) and the other on the funnel (often cartilaginous). The apparatus may permit some anterior–posterior displacement or prevent movement altogether.

Function

Variability

Funnel component

Six major forms of the funnel locking apparatus are recognised among teuthids (lazy-T shape, inverted-T shape, straight shape, triangular shape, oval with tragus and/or antitragus, and oval shape) and several more are found in the sepioids (including the boomerang shape and keyhole shape).

Shape of funnel locking apparatusSpeciesFamily
Idioteuthis cordiformisMastigoteuthidae
Magnapinna talismaniMagnapinnidae
Mastigoteuthis flammeaMastigoteuthidae
Mastigoteuthis glaukopisMastigoteuthidae
Mastigoteuthis grimaldiiMastigoteuthidae
Mastigoteuthis magnaMastigoteuthidae

Mantle component

Shape of mantle locking apparatusSpeciesFamily
Mastigoteuthis grimaldiiMastigoteuthidae