Madrella ferruginosa from Fremantle, Western Australia

Dear Brent,

Yes this is M. ferruginosa. You will see on the Forum that there are photos showing animals as dark as yours. Most photos in books - and mine on the Fact Sheet - are brightly lit so we can see some detail. On the dark brown bryozoan the feed on they are almost invisible. The 'bristling' of the dorsal papillae that you describe is almost certainly a defensive behaviour. These animals don't have defensive cnidosacs, like the aeolids, but it is possible they have distasteful glandular secretions. They have a sac at the base of the papillae which can exude a yellowish secretion when they are disturbed. It seems to be based on waste fron the digestive system and so is most probably from their bryozoan food. Again, we don't know if it has a defensive purpose.

This species has been reported from southwestern Australia, but it has been misidentified as Madrella sanguinea, which is a smaller, bright red species, apparently endemic to southern Australia.

Best wishes,
Bill Rudman