A redescription of the Indo-West Pacific Spirobranchus corrugatus Straughan, 1967 (Serpulidae, Polychaeta), and an alternative hypothesis on the nature of a group of Middle Miocene microfossils from Poland

Spirobranchus corrugatus, a little known species, is redescribed based on ample material from Australia, Indonesia, Japan and the Seychelles. The species is characterized by a seemingly porous tube, sunk into the substrate. Characteristically, the opercular plate shows a number of radial ridges on its distal surface, resembling Middle Miocene microfossils from Poland. The ventral rim of the opercular bulb of Sp. corrugatus bears numerous ocelli, with single lenses. A comparison with similar species is given.