A new species of the complex, (Annelida, Polychaeta, Serpulidae), from the rocky intertidal zone of Japan.

A new species of (Annelida: Serpulidae) is described based on specimens collected at the coastal Shonan area of Sagami Bay and the adjacent areas of Honshu, Japan. forms large aggregations in the intertidal rocky zone of warm-temperate Japanese shores. This species was referred to as (Baird, 1864) until the monotypic genus was synonymized with . This new species is formally described based on morphologically distinct Japanese specimens with supporting DNA sequence data. The calcareous opercular endplate of lacks a distinct talon, but some specimens have a slight rounded swelling on the endplate underside, while in other species of the complex a talon is present, usually extended, and with bulges. We examined sub-fossil tube aggregations of the new species and suggest that such aggregation stranded ashore is a good indicator of vertical land movements (uplift and subsidence) resulting from past events, such as earthquakes, in Honshu, Japan.