A new species of an unusual polychaete genus Ctenophoricola (Phyllodocida, Phyllodocidae, Alciopini) from the Indian Ocean.

A new species belonging to an unusual polychaete genus Ctenophoricola is described as Ctenophoricola tzetlini sp. nov.. The new species differs from the two valid species of the genus in body proportions and in having: external eyes with well-developed cornea resembling those in free-living Alciopini, acicular chaetae in the anterior body region, a large pygidium with long anal cirri, and distinct bundles of cilia scattered over the posterior body region. The new species' similarity to an undescribed Ctenophoricola sp. from the Gulf of California is discussed. We hypothesize that the genus Ctenophoricola consists of two lineages, one strongly specialized as ectoparasites and the sister group closer to free-living Alciopini.