Elysia from Gulf of Mexico

Thanks Anna,
I look forward to some comments from Kathe Jensen about this animal. I am depressed every time I look at Eveline Marcus's revision of the western Atlantic Elysiidae and see how little importance she attached to the colour of the living animals. She in fact says "The often beautiful colours of the living animals may be distinctive, but in most cases the colour is not decisive for the classification, as colours are frequently lost by preservation". What she basically is trying to do is justify her practice of describing new species from a few preserved specimens. Even in this revision, she describes another new species from ONE preserved specimen of which she had no information on the colour of the living animal. In fact the name patina that she gave this 'species' refers to the greyish colour the specimen had in alcohol. It would be amusing if it were not so pointless. I am sure there will be many wasted hours spent trying to determine the indentity of E. patina. I can't see why it was necessary to give one preserved specimen a scientific name.

There are going to be continuing identification problems with the west Atlantic species until the living animals are described adequately, and hopefully, matched with Marcus's anatomical descriptions. I realise that some species may have variable colours, depending on their diet, just like some Indo-West Pacific species do, but that just means that descriptions need to be more detailed and based on more than 2 or 3 animals.

• Marcus, Ev. (1980) Review of western Atlantic Elysiidae (Opisthobranchia Ascoglossa) with a description of a new Elysia species. Bull. Mar. Sci. 30(1): 54-79.

Best wishes,
Bill Rudman