Large sea slug? from Sydney Harbour

December 18, 2001
From: Andrew Trevor-Jones

While doing a night dive (14 December 2001) off Camp Cove, Sydney we saw a number of what looked like large sea slugs of some kind but I am unsure of the species.

The were 15-20cm long and a pale pink to orange in colour with darker spots. The "head" was shaped like a large arrow head or Napolean's hat and was 50% wider than the body. There was a noticeable mantle. They were quite flat and we found them gliding across the sand. If we picked them up and let them go in the water column, they swam with an undulating motion much like a Spanish Dancer.

They were in 2-4m of water and all were seen on sand.
Andrew Trevor-Jones

Trevor-Jones, A., 2001 (Dec 18) Large sea slug? from Sydney Harbour. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Andrew,
Sometimes this amount of description is enough to identify something but I am afraid in this case I am not sure what you have. If it they were sea slugs there are a couple of animals which are adapted to burrowing in sand and have a wide 'head' much as you describe - but their colour is not very similar to what you describe.

Have a look at the photos of Euselenops luniceps and Kalinga ornata. Another vague possibility is Aplysia extrordinaria but mainly because it swims.

The problem with somewhere like Camp Cove, is that you may have seen a permanent resident of the harbour or a tropical visitor which may be here only for a short duration. If you can end me a drawing it might help. I may have seen a group of flatworms. Can you remember any details like tentacles, head, gills, foot etc?
Best wishes,
Bill Rudman

Rudman, W.B., 2001 (Dec 18). Comment on Large sea slug? from Sydney Harbour by Andrew Trevor-Jones. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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