Re: Glossodoris vespa endemic to sthn Queensland

Dear David,
Thanks very much. You are probably correct in thinking I won't be able to get the sponge identified. I must say I used to think sponges were very good at keeping themselves clean of growths, and some certainly are, but unfortunately some of the main food choices of chromodorids seem to have evolved the ability to cope with being almost completely overgrown.

At the risk of seeming greedy, it would be nice to see a photo of this species' egg ribbon. As far as I know the only record is Nerida Wilson's report (2002) of a single egg ribbon, with whitish cream eggs, from the Gneering Shoals.

You are probably right in suggesting its direct development has restricted its geographical distribution, but there are some amazing exceptions to the rule that direct development means restricted distributions. One that comes to mind is Vayssierea felis which is a small species with a large Indo-West Pacific distribution. However this anomaly can be explained by its habit of living on floating algae which means the eggs rather than the larvae can be moved large distances. Another more spectacular example is the bright red sea anemone, Actinia tenebrosa, which is found all around New Zealand, and temperate Australia, and as far north as Shark Bay on the west coast and Heron Island on the east coast. Its main means of reproduction is to bud off small clones which pop out of its mouth to form a little cluster of babies on the rock around the parent. You can't get much more direct than that. One would expect populations to be genetically isolated, but a number of comprehensive studies suggest there is as much genetic variability as you would expect in a species with planktonic larvae. I don't know what it all means other than to be cautious of saying direct development always means a restricted distribution.

• Wilson, N. G. (2002). Egg masses of chromodorid nudibranchs (Mollusca: Gastropoda: Opisthobranchia). Malacologia, 44(2): 289-305

Best wishes,
Bill Rudman