Four new species of Provanna Dall (Prosobranchia, Cerithiacea?) from East Pacific hydrothermal sites

Abstract

Four new species of Provanna Dall, 1918 are described from East Pacific hydrothermal sites: Provanna ios sp.n., P. goniata sp.n., P. echinata sp.n. and P. variabilis sp.n. The type species of Provanna, P. Iomana Dall, 1918 and Trichotropis (Cerithioderma) pacifica Dall, 1908. which here is transferred to Provanna, are the only additional species known of the genus. Results of some preliminary anatomical investigations are given and a tentative position in the Cerithiacea is suggested. The four new species were collected by manned submersibles from sites of hydrothermal activity; P. Iomana has been dredged on two occasions only. from an area known for hydrothermal activity and we assume that the type‐ and only known locality for P. pacifica also is affected by hydrothermal acitivity.