Smiling Armina from Bonaire

July 18, 2008
From: Ellen Muller

Dear Bill,

On a night dive in Bonaire, [Lesser Antilles, Caribbean] April 10th 2008, I found five "Smiling Arminas". One was dead and lying belly up in the sand. The other four were alive and healthy, crawling along the sand.

The next night I found six Armina in the same area. All were crawling on top of the sand. Near the end of the dive I came across a pair that I suppose was mating, one was partially buried in the sand and the other was almost completely buried.

I went back again the next night and found 7 Armina in the same area. The Armina were in an area that was approximately 50 ft in diameter and were found between 7 ft-13 ft depth. Their sizes ranged from approximately 3/4 inch to 3 inches long. The Armina that were crawling on the sand were not particularly close to one another, usually several feet apart from each other.

Over the next three weeks the Armina were still in the same area and on one evening I counted 13. I observed the Armina on several occasions hunting and feeding on the plentiful Sea Pansies in the area [lower photo ]. One of the juvenile Armina had no "smile".

I used a red light to photograph them because they would quickly bury themselves in the sand if disturbed by a white light.

Ellen Muller

Muller, E., 2008 (Jul 18) Smiling Armina from Bonaire. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Ellen,

Thanks for these interesting observations. I couldn't resist putting a couple of 'smiling' Armina at the top of your message. In fact that black mark on the oral lobe is, I think, a clue to its identity, and your photos showing some with a large smile, and others without, is a valuable link to the Marcus's original description of Armina wattla  in which they illustrate a black median band just has seen in the animal eating the sea pansy in your lower photo. I am surprised to see in Caribbean Sea Slugs that they consider A. wattla and A. abbotti to be synonyms while Néstor Ardila [message #12433] considers A. abbotti and A. muelleri to be synonyms. Personally I don't think we have enough information to ever identify A. muelleri, but I suspect A. wattla will always be recognisable from its smile.

Best wishes,
Bill Rudman

Rudman, W.B., 2008 (Jul 18). Comment on Smiling Armina from Bonaire by Ellen Muller. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Armina cf. wattla

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