Taxonomy and nomenclature of black nerites (Gastropoda:Neritimorpha:Nerita) from the South Pacific

Abstract

Members of the genus Nerita are abundant components of the intertidal fauna in many parts of the world and yet Nerita taxonomy remains unsettled. Here, the relationships among black-shelled Nerita populations from Australia, New Zealand, Norfolk Island, Lord Howe Island, the Kermadec Islands and Easter Island are discussed. Four species are recognised: N. atramentosa Reeve, 1855 from the southern half of Australia; N. melanotragus E.A. Smith, 1884 from eastern Australia, northern New Zealand, Lord Howe Island, Norfolk Island and the Kermadec Islands; N. morio (G. B. Sowerby I, 1833) from Easter Island and the Austral Islands; and N. lirellata Rehder, 1980 from Easter Island alone. These species are of great importance in studies of intertidal community structure and yet two of them have been consistently confused in the ecological and taxonomic literature. Moreover, the relationships among the species are not at all as implied by recent subgeneric classifications; it is argued that all four species should be placed in the subgenus Lisanerita Krijnen, 2002. The superficially similar N. picea Récluz, 1841 is not closely related. An accurate taxonomy of the genus will almost certainly require considerable genetic analysis. The nomenclature for each species is herein established by complete synonymies, and lectotypes for both N. atramentosa and N. melanotragus are selected.