Re: Aeolid from the Philippines (2)
October 27, 2009
From: Erwin Koehler
Concerning message #6639:
Dear Bill,
here are some more pictures of the unidentified aeolid, larger and better. I know you like pictures where they are doing something, so here is one on its possible food.
Locality: Dauin, Lipayo, Negros Oriental, 6m , Philippines, Pacific Ocean, 08 May 2003. Length: 11 mm, 14 mm and 12 mm. Photographer: Erwin Koehler.
By the way, at Nudi Pixel this one is identified as Antonietta janthina
http://www.nudipixel.net/species/antonietta_janthina/
I hope this helps somehow
Erwin
erwin@philippine-sea-slugs.com
Koehler, E., 2009 (Oct 27) Re: Aeolid from the Philippines (2). [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22708
Dear Erwin,
Thanks for these extra photos. I note on NudiPixel that Richard Willan has some doubts about identifying this as Antonietta janthina and so do I. certainly the non-Japanese animals have some similarities in colour to Japanese material, especially the colour of the rhinophores and traces of the colours on the head and oral tentacles. However the thinner and longer shape of the cerata in Japanese animals looks rather different, but perhaps animals can change the shape of their cerata - perhaps something to do with how recently they have eaten. Opposed to that is the fact that all the non-Japanese animals seem to have fatter and shorter cerata. Also, one of the photos on NudiPixel shows a coiled egg ribbon which looks rather different from that laid by Japanese animals where the egg ribbon is divided up into short packets.
Interestingly Japanese animals are said to feed exclusively on the hydroid Hydractinia epiconcha which, as its name suggests, is found growing in clusters on snail shells. Your photo shows it feeding on a solitary hydroid, quite a bit larger than any Hydractinia I am familiar with. They are both athecate hydroids so if it is A. janthina it may feed on both.
Until we know more about its anatomy I think it would be better to call it Antonietta cf. janthina
Best wishes,
Bill Rudman
