The razor shells of the eastern Atlantic, part 2. Pharidae II: the genus Ensis Schumacher, 1817 (Bivalvia, Solenoidea)

The razor shells of the genus Ensis Schumacher, 1817, from the eastern Atlantic coast are revised. There are six species in total: the native European species Ensis ensis (Linne, 1768), E. magnus Schumacher, 1817, E. minor (Chenu, 1843), and E. siliqua (Linne, 1758), the tropical West African species E. goreensis (Clessin, 1888) and the introduced species E. directus (Conrad, 1843), originally distributed along the northeastern United States and Atlantic Canada and now wellestablished in Europe between southeastern Norway to the coast of Normandy. It is shown that the well-established name E. arcuatus (Jeffreys, 1865) falls into the synonymy of E. magnus Schumacher, 1817, and that E. directus (Conrad, 1843) and E. americanus (Binney, in Gould & Binney,1870) are conspecific. Furthermore, the names introduced by Van Urk between 1964 and 1984 are placed into the synonymies of their relevant nominate species because of the numerous existing intergrades. The story of the introduction of E. directus, now a major element of the marine invertebrate fauna in the southern North Sea and the Channel, is summarized. An identification key to the eastern Atlantic Ensis is provided.