Thorunna australis in the Marshall Is.

August 18, 1999
From: Scott Johnson

Hi Bill,

Attached is some photographic evidence that Thorunna australis occurs as far east as the Marshall Islands. It is relatively common at Kwajalein and Enewetak Atolls. This pair is on its typical prey sponge, a light grayish brown encrusting species. Also, the larger of the two is carrying around a commensal copepod.


Johnson, S., 1999 (Aug 18) Thorunna australis in the Marshall Is.. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Scott,
Thanks for the distributional information and the great photo. If colour is anything to go on in copepod taxonomy, I think I have found it on a number of nudibranchs. That white cross-like mark on its carapace is fairly characteristic - though for all I know it may be a family characteristic in copepods! See my photo of one on a phyllidiid.

A feature of great interest is the swollen orange region at the posterior end of the mantle in both animals. This is where the main mantle glands are concentrated in this species, but I have never seen them so obvious as in this photo.
Bill Rudman.

Rudman, W.B., 1999 (Aug 18). Comment on Thorunna australis in the Marshall Is. by Scott Johnson. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Thorunna australis

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