Colour variation in Chelidonura berolina

Dear Marina,
Thanks for this collection of photos showing the colour variation in C. berolina. This is indeed more evidence showing this species should really be identified as the eastern Atlantic species C. africana. I think we can say that the basic colour pattern is black with a yellow border to the parapodia and posterior shield and a yellow band across the head, some distance back fron the edge. Often the yellow lines are broken into a series of spots, and in some cases the yellow is absent. There are blue spots forming a sub marginal row on the parapodia and there can be blue spots on the inside of the 'tails' of the posterior shield. The blue spots can sometimes be absent, and sometimes are greatly enlarged.

There is a wide translucent white band across the front of the head shield. In most animals, but not all, there are white specks and patches scattered over the body. Sometimes the white predominates, producing an animal which could be best described as white with black speckling. There is usually a large white patch on the posterior tip of the head shield, which can sometimes be yellow or edged in yellow. Colin Redfern's photo [#12445] also suggests that the background colour can at times be brown rather then black.

You ask whether the animal in Photo F is the same? I am sure it is a colour variety. If you look at one of Anne Dupont's earlier messages [#9573] you will see an animal with similar broad transverse orange-yellow bands, but in that case the body is covered in white speckling, and is associated with a population of other animals with little sign of yellow on their bodies.

Re-looking at the Marcuses' descriptions, it is possible that C. hummelincki is a colour form of C. berolina, the difference I mentioned in the posterior 'tails' may be a result of preservation. However, as I said previously [#9573], the lack of any information on its living colour make its identification impossible.

With this extra information I think it is worth discussing the identity of this species in more detail. I have done this in a separate message [#12457]. I have little doubt that this is the same as the eastern Atlantic species Chelidonura africana.

Best wishes
Bill Rudman