About Goniobranchus annulatus (Eliot, 1904)
Goniobranchus annulatus is a large, smooth nudibranch that typically has a pale body covered in many bright yellow spots, though some individuals lack these yellow spots entirely. This species has a purple ring surrounding its gills and a second purple ring surrounding its rhinophores. The mantle usually has a purple border, and the gills are triangular in cross-section. Fully grown individuals can reach a total length of 100mm. This nudibranch was first described from specimens collected in Zanzibar. Its natural range covers the Red Sea and the Indian Ocean, stretching from the east coast of South Africa to Thailand. It is a Lessepsian migrant that has recently invaded the Mediterranean Sea, most likely entering through the Suez Canal.
