Habitat: Jetty pylons and rocky reef on sponge, occasionally under rocks
Depth: Lower intertidal to shallow subtidal
Rostanga calumus egg ribbon
Underside view
This small dorid nudibranch is usually found on microcionid sponges, including Clathria, which it eats. It is reddish brown, with white patches around the mantle and brownish colouration on its rhinophores, and has transparent spicules on its body. Like the similar Rostanga crawfordi, it can be recognised by its distinctive crater-like gills, but that species is generally much paler than R. calumus.
