Flamboyant cuttlefish

A small cuttlefish, mantle to about 8 cm, with a broad oval body carrying three pairs of large flat flap-like papillae on the upper surface. At rest it is dark brown. Disturbed, it flashes black, dark brown and white with yellow patches around the mantle, arms and eyes, and the arm tips flush bright red. The structural character behind all of this is the cuttlebone, which is only two thirds to three quarters of the mantle length and rhomboidal with no outer cone — unique among cuttlefish, and too small to provide much buoyancy. That is why the animal walks rather than hovers, ambling over the bottom on its ventral arms and mantle flaps. In the field the reliable call is the walking gait, the yellow and purple flashing and the red arm tips together; nothing else in the region does all three. Note the name: WoRMS now places it in Ascarosepion, following a 2023 revision that absorbed Metasepia, but every field guide and photo caption still says Metasepia pfefferi.

Diurnal and actively hunting by day, stalking small fish and crustaceans while running through a repertoire of camouflage patterns. Mating is head to head, and eggs are laid singly into crevices, coral, rock or wood, white at first and becoming translucent as they develop. Hatchlings emerge able to produce the adult camouflage patterns immediately. Recorded on sand and mud between about 3 and 86 m. On the toxicity: the widely repeated claim that its flesh is as poisonous as a blue-ringed octopus traces to a television programme and a field guide, not to any published assay, and the one analysis reported found only trace tetrodotoxin in muscle at concentrations too low to harm a vertebrate. It is a claim in wide circulation with nothing published behind it either way.