Little is known about the seaslugs in the Mexican coast of the Gulf of Mexico and almost all the species reported are either large or have a well-developed calcareous shell. Through specific sampling methods focused in opisthobranchs fauna, in two lagoons and three coral reefs of the Campeche Bank, Yucatan Peninsula, we have recorded 51 species belonging to the clades Cephalaspidea, Aplysiomorpha, Sacoglossa, Eutenidiacea, and Cladobranchia.

 

Of these, 30 species had not been previously reported for the Campeche Bank and 20 out of those are new records for the Atlantic coast of Mexico. The nudibranch Tambja cf. tenuilineata could be the first record for the east coast of the Atlantic Ocean. With this study, the actual number of opisthobranch fauna in the Campeche Bank are 84 species.