2026 · Photo: Boaz Liebes
Favorinus tsuruganus
Black-horned egg-eater
Philippines · Indo Pacific - South China Sea
- Size
- 10–20 mm · max 30 mm
- Native range
- Indo-West Pacific, from the Red Sea and Réunion to Japan, eastern Australia and New Zealand
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Description
A slender, translucent aeolid that is a specialised predator of other sea slugs' eggs, including those of the Spanish dancer Hexabranchus sanguineus. Unlike some congeners, its colour stays the same regardless of what it eats.
Share link: https://seaslugs.org.il/species/favorinus-tsuruganus-phillipines-indo-pacific-south-china-sea/
Identification
Almost colourless body with a faint yellowish head. Deep black rhinophores with two or three cup-shaped swellings partway up. Very long, slender oral tentacles, longer than the rhinophores. Spindle-shaped cerata with a bright orange-yellow core and a conspicuous black mark near the tip.
Similar species
Other Favorinus change colour with their egg diet; F. tsuruganus keeps its orange-yellow cerata with black subapical marks and black, swollen rhinophores.
Habitat & diet
Habitat
Rocky shores and reefs, on or near egg masses of other sea slugs; recorded around 14 m.
Food
Eggs of other sea slugs, e.g. Hexabranchus sanguineus and Goniodoris.
