Noumea sudanica and food sponge from Egypt

Dear Jason,
This is an interesting find on two counts. Firstly the white animal is Noumea sudanica which you will see from other messages on the page is a species we know little about and is only known from the Red Sea. Any information on it is very useful. Secondly it looks like both species are feeding on this sponge, which is a useful bit of information. I have copied you message on to the Chromodoris tinctoria page, with some closeups of the sponge, as a cross-reference.

Externally, Noumea sudanica can be distinguished by the darker pits, sometimes yellowish, scattered over the white mantle, and yellow mantle margin, and the translucent white gills and rhinophores which are edged in white. Like a number of species of Noumea, the mantle, when the animal is at rest, forms a rounded lobe midway down each side of the body.
Best wishes,
Bill Rudman