Sclerodoris prea? from Veracruz, Mexico

Dear Rodrigo,
I am pretty sure this is the same as the animal identified as Sclerodoris worki Marcus & Marcus, 1967 in Caribbean Sea Slugs. The general colour of the animal and the shape of the tubercles seem to fit. However I don't think this is the animal that Marcus & Marcus described as Anisodoris worki. In particular, Valdes et. al. in Caribbean Sea Slugs describe the mantle as being 'covered with numerous tubercles forming cauliflower-like structures with an apical knob surrounded with smaller tubercles'  They are apparently describing the compound tubercles we can see in your photo and in their photos. However I don't think describing them as 'cauliflower-like' describes their shape at all. In the original description Marcus & Marcus illustrate the notum as being covered in small rounded tubercles some larger than others and say 'the notal sculpture is cauliflower-like, as the interspaces between the larger papillae are filled with smaller ones.'  Valdes et. al. seem to have misunderstood that Marcus & Marcus were describing the whole dorsum as cauliflower-like, not the individual larger tubercles.  Nowhere in their lengthy discussion do Marcus & Marcus mention compound tubercles.

Marcus & Marcus also describe another tuberculate dorid, Anisodoris prea, which they describe as 'stiff' and having the notum 'covered with low flat knobs of different size, each big one surrounded by a number of small ones.' They also describe a row of larger tubercles on each side of the midline. Valdes et. al. place this species in Sclerodoris and their photo looks very similar to those they identify as S. worki.

My feeling is that your animal is Sclerodoris prea (Marcus & Marcus, 1967).

• Marcus, E. and Marcus, E. (1967) American opisthobranch mollusks. Part 1, Tropical American opisthobranchs. Studies in Tropical Oceanography, Miami, 6: 1-137.
• Valdes, A., Hamann, J., Behrens, D.W. & DuPont, A. 2006. Caribbean Sea Slugs. Sea Challengers. 

Best wishes,
Bill Rudman