Trapania sp. 8
Exmouth Gulf, 18m, Western Australia, Exmouth Gulf, Ningaloo Reef, 09 January 2004, tidal, silty bottom, small coral outcrops, large sponges. Length: 1.5 cms. Photographer: Kristin Anderson
Rudman, W.B., 2006 (February 26) Trapania sp. 8 [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/trapsp8
February 6, 2008
From: Kristin J Anderson
Concerning message #21295:
This is the first time in several years that I have come across Trapania sp. 8. There were three individuals in this big barrel sponge. Two were on the inside and one adventurous soul was on the outer surface (he had been inside with the other two earlier in the day).
Locality: Exmouth Gulf, 6m, Western Australia, Exmouth Gulf, 03 February 2008, silty, tidal. Length: 1-1.5 cms. Photographer: Kristin Anderson.
firstname.lastname@example.orgAnderson, K.J., 2008 (Feb 6) Trapania sp. 8 from Ningaloo Reef. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21361
Although I can't see any sign of them, I think we can be pretty sure that if these Trapania have clustered on this sponge, and have stayed there for some time, then their food is near by. I am not sure what this species of Trapania feeds on, but all others we have information on feed on small colonial animals called entoprocts or kamptozoa which are often found growing over sponge colonies.
February 28, 2006
From: Kristin Anderson
Here is a photo of Trapania aurata. Are these eggs from this little guy?
Locality: Exmouth Gulf, 18m, Western Australia, Exmouth Gulf, Ningaloo Reef, 09 January 2004, tidal, silty bottom, small coral outcrops, large sponges. Length: 1.5 cms. Photographer: Kristin Anderson
kristin@OceansByAnderson.comAnderson, K.J., 2006 (Feb 28) Trapania aurata?? with eggs Ningaloo. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15844
I don't think this is T.aurata, or for that matter another species from Western Australia that I am calling Trapania cf. aurata. Your animal, with white gills, orange rhinophore clubs, the whole of the lateral processes orange, and at least the posterior tip of the and the oral tentacles orange, is quite different in colour from those two species. I guess it is another unnamed species.
Concerning the egg ribbon. I remember finding a similar egg mass disorganised egg mass with some Trapania aurata I found in New Caledonia, so it is possible the eggs belong to your animal, but I can't be sure.