Noumea haliclona & C. splendida feeding

Dear Leanne & David Atkinson,

Thanks for these valuable photos which illustrate quite a few interesting features. Firstly, as I probably say too often, sponge identification can be very tricky, and one reason for this is that colony shape can change considerably even in different parts of the same colony. If you just had the two close-up photos I have included, you might think that the Noumea and the Chromodoris were feeding on different sponges, but as we can see in the upper photo, they are all part of the same colony. It is a species of Darwinella, perhaps an unnamed species. This is a valuable confirmation of the information we already have on both these chromodorid nudibranchs, which suggests they feed on a number of different species of darwinellid sponges, making them a little more flexible in their food choice than those that seem to feed on only one sponge species.

The third interesting feature these photos show is the remarkable similarity in colour pattern between the white N. haliclona and the C. splendida. As I discuss on the Noumea haliclona Fact Sheet there are a large group of chromodorids in south-eastern Australia which all have a similar red-spotted colour pattern, which I suggest is a co-operative warning pattern to deter predators.

Best wishes,
Bill Rudman