Phyllodesmium is a genus of aeolid nudibranchs in the family Myrrhinidae (per WoRMS and Wikipedia). They feed exclusively on octocorals and show remarkable camouflage, closely resembling their prey. Some species keep zooxanthellae taken from the prey and gain nutrition through photosynthesis. The genus occurs in the tropical Indo-Pacific and warm-temperate Japan, Tasmania and South Africa, and Wikipedia gives about 27 species.
Identification
The cerata resemble the tentacles of the soft coral the animal sits on in form and colour, and the animal relies on camouflage rather than warning colours. In P. briareum there are four groups of slender, club-shaped cerata along each side, light to olive-brown with darker markings.
Identification key (PDF) ↗
