Aegires albus from Antarctica

February 26, 2007
From: David Cothran

Hi Bill,

Here's one more from the same dive today at Grass Island. I really have no idea about this one - at first I thought a tiny Austrodoris, but that doesn't seem right on a close look.

It was quite small, about 10 mm, and swinging around while attached only by the distal end of it's foot, so this was the best shot I could manage.

Any ideas?

Locality Details: Grass Island, Stromness Harbor, South Georgia, Southern Ocean. 16 meters. Length 10 mm. 24 February 2007. Rock wall. Photo: David Cothran

Thanks again for your help.
Best regards,
David Cothran

Cothran, D.B., 2007 (Feb 26) Aegires albus from Antarctica. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear David,
This is Aegires albus. It is a nice find because as far as I know this is the first published photo of this species alive. It is similar in shape to other species of Aegires but one difference is that it still possesses a distinctive mantle edge which is absent in other species. Odhner (1934) considered the presence of a mantle edge to be enough erect a separate genus Anaegires, but Wägele (1987) reviewed the anatomy Aegires albus, and Odhner's type species of Anaegires, A. protectus, and decided that neither the new genus nor its type species were warranted.

Species of Aegires feed on calcareous sponges, so I suspect its presence amongst, what I assume are colonial ascidians, is a coincidence. If you get the opportunity, it would be interesting to know if Aegires albus also eats calcareous sponges.

This species has only been recorded from the Antarctic Peninsula, the Ross Sea and the Weddell Sea (Wägele 1987).

Best wishes,
Bill Rudman

Rudman, W.B., 2007 (Feb 26). Comment on Aegires albus from Antarctica by David Cothran. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Aegires albus