Chelidonura sp. from Fiji

February 9, 2002
From: Julian Sprung

See Nils Anthes message suggsting this may be C. flavolobata.

Dear Bill,
To accompany my message on Chelidonura hirundinina from Fiji, here is a photo of another species similar to C. inornata, that occurred with it.

This second species is dark blue-black (in bright sunlight the blue is obvious, otherwise it is not). The head has two white marks that look like "evil eyes." An interesting side note about this species is that it releases a brown iodine-looking substance when disturbed. The substance presumably is produced from its flatworm food - you may not know, but the flatworm
Convoluta triloba is reddish brown and releases a similar "juice" when killed, the juice being toxic. The brown juice from this Chelidonura stained my fingertips just like iodine. Both species occur together in abundance in shallow water on algae-covered rubble and sand.

Sprung, J., 2002 (Feb 9) Chelidonura sp. from Fiji. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Julian,
Yes this is an unnamed species, which I have seen a couple of animals of. I am interested in your mention of the yellow ink it produces from its mantle cavity. This yellow 'ink' is a character found in all aglajids, much like the purple 'ink' is only found in Sea Hares. The yellow ink is produced by a special gland which opens by the anus. I named it the not very original name 'Yellow Gland' to match the Purple Gland in Sea Hares. Have a look at the Yellow Gland page where there is a very good photo from Elianny Domínguez Tejo showing Navanax aenigmaticus 'inking'.

As with the Sea Hares, the function of this gland is a mystery. It is unlikely that the yellow pigment comes from the flatworms, because it is also produced by species of Navanax and Philinopsis which feed on bubble-shells and other opisthobranchs, and species of Melanochlamys which eat polychaete worms.

Another of life's little mysteries.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Feb 9). Comment on Chelidonura sp. from Fiji by Julian Sprung. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Chelidonura sp. 4