March 18, 2000
From: Yasuhiro Shirai
Thank you for your reply about Antonietta?.
Here are 2 more image files for reference.
I sometimes see these animals. When I saw them they were the same color as the photos. I think this animal's cerata do not change like Favorinus mirabilis.
email@example.comShirai, Y., 2000 (Mar 18) Re: Antonietta? from Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/2108
[Note added April 29 2005: See message #13442 suggesting this may be Favorinus perfoliatus]
Thanks for the extra photos. The only way to be sure of their identity would be to look at their anatomy. Having looked at the wide range of colour found in photos of Favorinus mirabilis on the Forum, I think it is quite possible that your animal is Favorinus mirabilis. At 5mm it is probably a juvenile and so may have not yet developed any of the 'adult' colour features such as white speckling on the cerata and a reddish mark in the anterior midline.
At this small size you would be unlikely to see any noticeable change in ceratal colour as both animals may have been feeding on their first egg mass.
Sorry I can't be more positive. Perhaps next time you find any, see if there is a purple egg mass nearby, or see if you can keep an animal alive on a different coloured egg mass and see firstly whether it eats eggs, which would suggest it is a Favorinus and if so, whether it changes colour on its new egg mass.