Molluscan diversity in the North Atlantic Ocean: new records of opisthobranch gastropods from the Archipelago of the Azores

New findings of opisthobranch gastropods are reported to the Azores resulting from fieldwork undertaken in the islands of Faial and Sa ?o Jorge (Central Group, Azores) during August 2007. Intertidal and subtidal areas down to 35 metres deep were sampled. Forty-four species were collected and eight are new records to the Azores, namely Chelidonura africana, Odontoglaja sabadiega, Aplysia juliana, Elysia flava, Thuridilla picta, Doris sticta, Catriona maua and Taringa armata. This increases the diversity of opisthobranchs in the archipelago to 141 species. Our results provide further support for the closer affinity of the Azorean marine diversity with the eastern Atlantic/Mediterranean Sea biota (75% of species) but they also show a biogeographic bound with the Caribbean province (25% of common species).