Thorunna australis from South Africa

October 10, 2005
From: Colin Ogden

Hi Bill,
I have another nudi that is confusing me.

Locality: Sodwana Bay, South Africa. Indian Ocean coast. Depth: 16 metres. Length: 5 mm. 1 October 2005. Coral reef. Photographer: Colin Ogden

At first I thought it was a tiny Hexabranchus sanguineus, but on further thinking, the closest I can come is the Hypselodoris maculosa. I am not happy about this so please can you help.
Thanks a ton

Ogden, C., 2005 (Oct 10) Thorunna australis from South Africa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Colin,
This certainly has the look of a juvenile Hexabranchus [message #14676], but I am glad you decided it wasn't, because this is a new find for the western Indian Ocean. It is Thorunna australis, which is at present known only from the western Pacific and Indonesian Archipelago. The orange bands on the gills and rhinophores, the rounded posterior end of the mantle with small rounded mantle glands, and the general colour pattern, are good characters for this species. Have a look at the Chromodoris decora colour group Fact Sheet
Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Oct 10). Comment on Thorunna australis from South Africa by Colin Ogden. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Thorunna australis

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