Unique pleuroproctic taxa of the nudibranch family Aeolidiidae from the Atlantic and Pacific Oceans, with description of a new genus and species

Abstract

Morphological and molecular data on a deep-sea pleuroproctic taxon of the family Aeolidiidae from the Barents Sea (subarctic North Atlantic) are presented for the first time. Zeusia n. gen. is established for the North Atlantic and North Pacific pleuroproctic species of the family Aeolidiidae with two species: Z. hyperborea n. sp. and Z. herculea (Bergh, 1894) n. comb. Zeusia was recovered as sister to the genus Aeolidia in molecular analyses. The two included species of Zeusia share the potential synapomorphies of very large seminal receptacle and long vas deferens. A pleuroproctic anal opening is an important basal character of the group Nudibranchia and the family Aeolidiidae is discussed in the light of the present discovery.