Parasitism among polychaetes: a rare case illustrated by a new species: Labrorostratus zaragozensis, n. sp. (Oenonidae) found in the Gulf of California, Mexico.

We describe a new species of polychaetous annelid from the family Oenonidae, Labrorostratus zaragozensis, n. sp., which is parasitic on another polychaete from the family Trichobranchidae (Terebellides californica). It can be differentiated from the other 4 species of the genus (Labrorostratus parasiticus, Labrorostratus jonicus, Labrorostratus prolificus, Labrorostratus sp.), basically by the shape of the mandibles and in the case of L. luteus, by the presence of hooded acicular hooks. Along with the description, a review and discussion of all previous records of the parasites in the Oenonidae and their related interactions with their hosts is presented.