Trapania brunnea? from Heron Island

April 9, 2001
From: Julie Marshall


Dear Bill,
I recently found what I think is Trapania brunnea at Heron Island which extends the range of this species in Australia. The pictured animal was 8mm in size and was found at the reef crest under a dead coral slab on 12th March 2001 at low tide.

Best wishes,
Julie Marshall

j.marshall@latrobe.edu.au

Marshall, J., 2001 (Apr 9) Trapania brunnea? from Heron Island. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4120

Dear Julie,
I have my doubts about whether your animal is Trapania brunnea. T. brunnea has a uniform dark brown background colour and the midregion of the lateral processes are also dark brown. There is also no sign of yellow in the white patches. Your animal has diffuse yellow markings in the white regions and has small pale spots all over the brown regions. It therefore has similarities to Trapania benni which has small yellow or white spots all over the body and yellow spots in the white patches, althpugh in T. benni the yellow spots are very distinctive.

Looking again at the photos Scott Johnson sent of some other 'potential' T. brunnea which I have temporarily placed on a Trapania cf. brunnea page it seems there may be a group of similarly coloured species or else there is considerable colour variation. I have included here enlargements of the heads of two of Scott's animals showing that the one on the right [e050b-4] has a uniform brown background but the one on the left [e050a-1] has a pattern of small spots like in your animal but has yellow oral tentacles which are indeed unusual. It seems there are still a few things to sort out amongst these brown species of Trapania so I am also putting your animal on the Trapania cf. brunnea page as well, so we don't forget about them.
Best wishes,
Bill Rudman

Rudman, W.B., 2001 (Apr 9). Comment on Trapania brunnea? from Heron Island by Julie Marshall. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4120