Painted nudibranch
Hypselodoris picta
— Where the name comes from
Doris, inside the genus name, is the Nereid who mothered the fifty sea nymphs, and she has named a whole family of these animals. Picta is “painted”. Nudibranchia, the order name, means “naked gills”: they have lost the shell and carry their respiratory apparatus exposed on the back, in a tuft, where anything could bite it — which explains why they are almost all venomous and brilliantly coloured.
— Facts
- Group
- Molluscs · Mollusca
- Order
- Nudibranchs
- Habitat
- Rocky bottoms with sponges, between 5 and 50 metres
- Range
- Mediterranean and eastern Atlantic
- Size
- 6–20 cm
- Diet
- Sponges of a few particular species
- Lifespan
- 1 year
— Characteristics
- 01
The colours are a warning: the flesh is toxic or foul-tasting.
- 02
It takes its chemical defences from the sponges it feeds on.
- 03
The two tentacles on the head, the rhinophores, retract at the least danger.
— What sets it apart
It does not manufacture its own poison: it buys it by eating. It feeds on a few species of sponge, which defend themselves with toxic molecules, and instead of neutralising them it concentrates and stores them in its own skin — then advertises the fact with a yellow and blue livery no predator forgets. It is the monarch butterfly’s system with milkweed, applied underwater. Some of these molecules are now studied as anticancer agents, and nudibranchs act as signposts: where there is one, there is a sponge making something interesting.
