Mexichromis antonii from Ecuador

May 31, 2010
From: Annika Mackensen

Dear Sir,
I am working with bivalves and currently investigating the epifauna of Spondylus species along the mainland coast of Ecuador. I found two nudibranchs, which I am unable to identify (however, I gues the first is some sort of Chromodoris?). I hope this is an easy task for a specialist, besides the fact that the pictures are not so good. I would highly appreciate any help with the family names or anything else.

Locality: Esmeraldas, 16-18 metres, Ecuador, Eastern Pacific, 8 April 2009, sandy bottom. Length: less than 2 cm. Photographer: Soledad Luna.

Thank you so much in advance,
Annika Mackensen

Mackensen, A.K., 2010 (May 31) Mexichromis antonii from Ecuador. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Annika,

I don't think we know very much about the opisthobranch fauna of Ecuador so your photos are of interest. The animal in your upper photo is indeed a chromodorid. I am sure it is Mexichromis antonii, although as you will see from the few photos on the Forum the central part of the mantle differs a bit in colour. This species is known from the eastern Pacific but I suspect Ecuador is much further south than it has been found before.

Concerning your second species. I prefer different species to be sent in different messages as it means they can be associated with a Fact Sheet. However I have no idea what this is. It may be a species of Dendrodoris but that is a guess. Hopefully someone with local knowledge may recognise it.

Best wishes,
Bill Rudman

Rudman, W.B., 2010 (May 31). Comment on Mexichromis antonii from Ecuador by Annika Mackensen. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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