A REVISION OF THE DEEP-SEA BARNACLES PACHYLASMA AND HEXELASMA FROM JAPAN, WITH A PROPOSAL OF NEW CLASSIFICATION OF THE CHTHAMALIDAE (CIRRIPEDIA, THORACICA)

Abstract

The deep-sea barnacles Pachylasma and Hexelasma are little known and a few species have been sporadically recorded from isolated localities of all oceans. Of the genus Pachylasma, only two species P. crinoidophilum PILSBRY and P.japonicum HIRO have been known from Japan. A third species P. scutistriatum BROCH is newly added to the Japanese fauna. The other known species, P. ecaudatum HIRO formerly referred to Pachylasma, is now transferred to the genus Hexelasma, of which two species H. velutinum HOEK and H. callistoderma PILSBRY only have been so far known from Japan. An attempt to subdivide the family Chthamalidae into three subfamilies (Catophragminae, Chthamalinae and Pachylasminae) is newly presented.