Spanish Dancer

Hexabranchus sanguineus

The Spanish dancer (Hexabranchus sanguineus) is a dorid nudibranch, a very large and vividly coloured sea slug and marine gastropod mollusc in the family Hexabranchidae. The genus has long been taxonomically contentious, and a detailed molecular and morphological study published in 2023 found that the name H. sanguineus had been applied to at least five distinct species.

Family

Hexabranchidae

Avg Size

20-40 cm

Habitat

It is recorded from the Red Sea, the Western Indian Ocean, French Polynesia and the Western Pacific, with a different colour morph in each region that cannot be told apart by anatomy or DNA barcoding. It favours rocky and coral reefs rich in sponges and shelters at depths from 1 to 50 metres.

Behaviour

By day the Spanish dancer keeps out of the light in crevices, emerging only late at night. Like all nudibranchs it is hermaphroditic, and its egg ribbons, coloured from bright red to pink, form a spiral whose size matches that of the animal. It feeds on sponges of the family Halichondriidae, drawing from them a potent chemical it uses for defence; it then channels these compounds into its egg ribbons as macrolides, giving the otherwise defenceless ribbons a chemical deterrent.

Where & When to See It

Shaab El Erg

Spanish Dancer

Where & When to See It

More Invertebrates