Tethys fimbria from Croatia

Dear Duncan,
Thanks for these interesting photos. Its nice to get a photo of the egg ribbon. In the close-up alongside you can see the rows of small white eggs. I guess your photo is of an animal swimming. Tethys fimbria is said to be quite a good swimmer but I don't know how it swims. I would be interested to know if it flaps its body from side to side or if it is one of those species which bends its body up and down?

I have also included a close-up of the 'head' [lower left] in which I have ringed the rhinophore, which is very small in this species.

You ask if I can tell you something about this species. Have a look at the Fact Sheet for this species, and at the other messages attached below yours on this page. You will see that this animal feeds by using its great oral veil to feel for and capture small crustacea [shrimps, crabs etc] in the sandy mud. It finds its prey by using the small sensory papillae on the edge of the oral veil to feel in the sand. Many nudibranchs find their food by using their rhinophores to smell chemicals in the water. I guess with Tethys the sense of smell is not very important, which would explain the small size of the rhinophores.

Tethys is closely related to Melibe, a genus of Indo-West Pacific nudibranchs. If you go to the Species List and look for the FAMILY Tethydidae, you will find links to a number of species which would be worth comparing with your animal.
Best wishes
Bill Rudman