September 21, 2007
From: jean-François Hervé
Could you help me to ID the two little limapontiids in this and the accompanying message [#20752] which we sometimes see on this algae. Maybe this is Costasiella ocellifera ?
Locality: Noumea, Ouemo Beach, 10 m, New Caledonia, Pacific ocean, July and January 06, Algae. Length: 5 mm. Photographer: Jean-François Hervé.
Hervé, J.-F., 2007 (Sep 21) Costasiella vegae from New Caledonia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20688
Costasiella ocellifera is pretty close, but that is considered to be a Caribbean species. I have identified your animal previously as Costasiella vegae, which seems to be the West Pacific 'version' of C. ocellifera.
All species of Costasiella seem to feed on green algae of the genus Avrainvillea which could well be the algae your animals are on. If you have a higher resolution photo showing the slugs in more detail I would like to add it to the Forum so we have a better idea of the colour pattern variation in this species.