Aphelodoris brunnea feeding?

Dear Charles,
When I first saw these photos I thought you had a Discodoris lilacina which often casts off parts of its mantle skirt as a defensive mechanism [see autotomy page]. The animal in your photo seems to have a very narrow mantle skirt down each side with the foot clearly visible.

It is Aphelodoris brunnea, a species known only from temperate South Africa. If you look at the two close-ups I have included you can see the raised pockets around the gill and rhinophore openings, a character of this genus. Your animal is almost identical in colour form to one in an earlier message from Lindsay Warren.

Concerning the problems of identifying species from the Forum. The point you raise is a fault with the Forum which I have recognised for some time [years in fact]. Two improvements I have been preparing are • an online identification guide which hopefully would allow you to identify animals to the genus level
• a thumbnail key where you could put in a few key words, for example 'yellow spots' and 'aeolid' and you would get a display of thumbnail photos of all the yellow-spotted aeolids on the Forum.

Unfortunately things like this take time and assistance, both of which are in short supply at present. All I can suggest at present is that you use the Forum's internal SEARCH engine and type in South Africa. The list is quite long thanks to the input of you, Valda Fraser and others.

Although providing identifications is time consuming it does allow the Forum to accumulate much valuable information on geographic distribution, colour variation etc. For example I am pretty sure the slug in your photos is feeding on the whitish sponge which you can see in the photo alongside. So don't feel bad about asking for an indentification. In most cases we both gain some valuable information.
Best wishes
Bill Rudman