Anna's Chromodoris

• It stores in its mantle the toxic compounds of the sponges it eats and advertises that toxicity with its striking colours: a case of aposematic colouration.
• The plumes at its rear are gills, and the horns on its head (the rhinophores) are chemosensory organs.
• It does not make its own chemical defence: it takes secondary metabolites from the sponges it eats and concentrates them in glands along the mantle edge, ready to be secreted if it is attacked.
• Its striking colours — blue, black and orange — are aposematic: they advertise that toxicity.
• Several species in the genus share very similar colour patterns despite not being close relatives, a case of mimicry between equally toxic species.
• Chromodorids tend to be highly specialised on a single sponge species.
• Like all nudibranchs, it is a simultaneous hermaphrodite and mates side by side, exchanging sperm in both directions.

Skeleton type

Invertebrate - no rigid skeleton (mollusc)

Habitat and environment

Coral reefs of the western Indo-Pacific, from 3 to 40 m

Sources consulted: Bergh (1877); Rudman, Sea Slug Forum; Frontiers in Zoology (2022); anatomia de Gastropoda