Rostanga at Fly Point

This is probably Rostanga bifurcata. Most species of the dorid genus Rostanga are orange or red, and apparently take up colour pigments from their sponge food so that their colour exactly matches the sponge they are feeding on. There are a number of species of Rostanga in south eastern Australia and they are difficult to separate externally. Differences in the shape of their rhinophores and gills can be useful but often they cannot be identified correctly until they are dissected and their radular teeth are studied with an electron microscope. One very good character is the shape of the egg ribbon, every species so far looked at has a distinctly differently shaped ribbon... Bill Rudman