Spinucella, a new genus of Miocene to Pleistocene muricid gastropods from the eastern Atlantic

The new muricid gastropod genus Spinucella is proposed for Purpura tetragona J. de C. Sowerby, 1825 (type species), from the Pliocene of the North Sea Basin, and for several other early Miocene to late Pleistocene species from southern Europe, North Africa, and southern Africa. The genus is characterised by the presence of a labral spine on the outer lip of the shell and by reticulate sculpture. Species of Spinucella closely resemble members of Nucella Röding, 1798, Acanthina Fischer von Waldheim, 1807, and Acanthinucella Cooke, 1918. The labral spine of Spinucella was probably evolved independendy of that in the eastern Pacific Acanthina and Acanthinucella. With the removal of S. tetragona from Nucella, where many recent authors have placed the species, the time of arrival of Nucella in the North Atlantic from the North Pacific was late Pliocene, rather than middle Pliocene.