Rhinophore shape of Cratena cf. affinis

December 17, 2002
From: Nishina Masayoshi

Dear Bill,
To accompany my other photos, here are photos of the close-up of the rhinophores. I agree with your opinion that "the 'rings' on the rhinophores seem to be a series of radiating papillae rather than a solid plate. However the don't seem so clear in some of the other photos,"

The rhinophores rings in these photos are rather wavy. I suspect that the radiating papillae shaped 'rings' are because of some damage or on the way of regrow? or just a variation? This animal often found on the reddish coral. So I suspect it's the their diet.

All photos by M. Nishina on Hachijo Island.
Date: 7 Dec, 2002. Size: 6mm-8mm

Best Regards,
Nishina Masayoshi


Thanks Nishina,
The structure of the rhinophore plates is a bit difficult to determine from the photos but does seem to be quite variable. In the top photo there seems to be a posterior notch or break in the plate, while in the lower left photo there seems to be a very wavy edge as you describe. Concerning its food. I would be surprised if it was eating the coral, but it is possible that there is a hydroid that is growing in association with the coral and appears as single red polyps, on a short stalk, scattered over the coral colony.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Dec 17). Comment on Rhinophore shape of Cratena cf. affinis by Nishina Masayoshi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/8673

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