Rediscovery of Elysia trilobata from Red Sea

March 14, 2005
From: Binyamin Koretz

Hi Bill,

Last month, I sent you a couple of poor photos of what looked like a small Elysiid sp. [message #13166], which as yet you haven't posted. We have encountered this slug several more times in the same vicinity, and now we have some halfway decent photos.

Locality: Eilat, Tables South, Israel. Red Sea (Gulf of Eilat). Depth: 28 m. Length: ca 1.5 cm. 04 March 2005. sea grass. Photographer: Binyamin and Shulamit Koretz

Best regards

Koretz, B., 2005 (Mar 14) Rediscovery of Elysia trilobata from Red Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Binyamin,
Sorry I hadn't posted your earlier message but the photos didn't give me any clues to its identity so it was waiting in the 'difficult' basket. However as soon as I saw these photos it reminded me of a species described from Sudan on the basis of one small specimen - Elysia trilobata Heller & Thompson, 1983, and after re-reading their description I am sure that is what your animal is. This is the first record of it since that description in 1983 and so is a very valuable contribution to our knowledge.

I must admit I thought this species must have been based on a damaged, perhaps half-eaten animal, the shape of the [parapodia appearing very strange in Heller & Thompson's drawing. I can see from your photos that their drawing was quite accurate - but the shape is still very strange. In fact in the upper right animal it almost looks as though there is a gap on the right side, between the anterior and middle lobe of the parapodia, making it look as though it has been bitten. I have posted your earlier message as well, as the photos in that message show animals that are not fully extended. In that condition the 'trilobate' shape is not so clear.

  • Heller, J. & Thompson, T. E. (1983) Opisthobranch molluscs of the Sudanese Red Sea. Zoological Journal of the Linnean Society, 78: 317-348.

Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Mar 14). Comment on Rediscovery of Elysia trilobata from Red Sea by Binyamin Koretz. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Elysia trilobata

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