Rostanga rubra

(Risso, 1818)

The body length may reach 15 mm (20 mm in the Mediterranean Sea at Naples), bright scarlet (rarely yellowish) in the typical variety, with scattered black spots dorsally and a characteristic yellowish patch between the rhinophores. The ample mantle bears innumerable close-set, short, blunt, spiculose tubercles. There may be up to ten simple pinnate yellowish gills; the lamellate rhinophores are the same colour. Finger-like oral tentacles project from the sides of the head. The propodium is bilaminate, the anterior lamina notched in the midline.

This conspicuous species feeds upon red sponges such as Microciona atrasanguinea , in shallow waters.

It has been recorded from Norway to the Mediterranean Sea (Villefranche and Naples), to 60 m (Distr. R. rubra).