September 26, 2001
From: Julie Marshall
Following your message about Eubranchus cf. rubropunctatus from Hong Kong I am attaching a picture of Eubranchus rubropunctatus from Heron Island. I have found eight specimens in all, ranging in size from 6 to 10 mm, and all have the red spots in the band below the cnidosac region. I have found that the red spots can vary in colour from red to dark purple to almost black. The Hong Kong specimens also seem to lack the tubercles on the rhinophores as described by Edmunds and which can be clearly seen in the Heron Island animal. Edmunds description was based on only one animal which was 4 mm. The larger specimens from Heron Island show the tubercles more strongly developed.
• Edmunds, M. (1969) Opisthobranchiate Mollusca from Tanzania. I. Eolidacea (Eubranchidae and Aeolidiidae) Proceedings of the Malacological Society of London, 38: 451-469.
• Marshall, J.G and Willan, R.C. 1999. Nudibranchs of Heron Island. Leiden, Backhuys Publishers. (Eubranchus rubropunctatus, pp. 138-139, 251)
email@example.comMarshall, J., 2001 (Sep 26) Eubranchus rubropunctatus from Heron Island. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4869
Your animal certainly fits better than the Hong Kong one. It's unfortunate that quite a few aeolid species seem to be described from single juvenile specimens. In Malcolm Edmund's case he gave a description of the colour of the live animal, which is a great advance on the many species that have been described over the years from preserved decolourised animals. It is just unfortunate that colour and some body details change quite considerably as an animal grows, and often there is considerable colour variation within adults of a particular species. Describing species from a single specimen, adult or juvenile, can cause major problems.