Runs bands of colour down its arms at a crab in the seconds before it strikes.
The largest cuttlefish in the region, reaching about 50 cm and several kilogrammes. The mantle is broad and rounded, fringed the whole way by a narrow undulating fin, and the skin can be raised into large flaps and papillae over the eyes and along the back. Colour runs from pale sandy grey through mottled brown to near white, changing in under a second. The name refers to the broad, club-like tips of the fourth arm pair in males. Size alone separates it from the other cuttlefish on a muck site.
Hunting is worth watching for the display that precedes it. Approaching a crab or a small fish, the animal turns the two broad dorsal arms towards the prey and runs bands of dark colour down them in a fast repeating wave, holding the pattern for several seconds before the feeding tentacles fire. The effect on the prey has been argued over for decades and is not settled; what is certain is that the display is consistent, directed at the prey, and unmistakable once seen. Eggs are laid singly, pushed deep between the branches of living hard coral. Recorded from the shallows to about 30 m.
Older references list it as Sepia latimanus.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
