A hot-vent gastropod with iron sulfide dermal sclerites.

Abstract

1, C and D). The dominant crystalline mineral phase is pyrite, whereas greigite, the sulfide analog of magnetite, is present in lower proportions and accounts for the ferrimagnetism. The interior of the sclerites is penetrated by a pulp of pedal tissue that extends almost to the tip. Between the pulp and the outer mineralized layers there is a tough, laminated, organic layer, histologically indistinguishable from molluscan conchiolin. The conchiolin is studded with minute (typically about 1 m in diameter) iron sulfide granules and finely dispersed iron sulfur compounds; these minerals are more common in the outer layers of the conchiolin. Where the sclerite surface is overlain by adjacent sclerites, the sclerites are covered by a coat of bacteria (Fig. 1C; fig. S2G). Iron sulfide as a skeletal material is not known in metazoans (4), although accumulations of metal sulfides occur in animal tissues