Labrorostratus Saint-Joseph, 1888

Steiner, Tatiana M. & Amaral, Antonia Cecília Z., 2009, Arabella aracaensis, a new species with growth rings on its mandibles, and some remarks on the endoparasitic Labrorostratus prolificus (Polychaeta: Oenonidae) from southeast Brazil, Journal of Natural History 43 (41 - 42), pp. 2537-2551 : 2539

Labrorostratus Saint-Joseph, 1888

Type species: Labrorostratus parasiticus Saint-Joseph, 1888, p. 221 , pl. IX, figures 77–85.

Diagnosis

Prostomium without antennae. One or two pairs of small maxillae, sometimes reduced to one pair of broad plates without teeth. One pair of long maxillary carriers, partially or completely fused, sometimes with an additional unpaired one. Mandibles present. Parapodium uni- or sub-biramous, with notopodium composed of an external papilla and an internal aciculum. Setae simple, geniculate; modified ventral seta sometimes present. Acicular spines absent. Pygidium rounded, with up to four small anal cirri.

The previous diagnosis is based on all the species described until now, and therefore differs from the original diagnosis of the genus. According to Fauchald (1977), Labrorostratus was created to accommodate species with the acicular spine absent, two pairs of maxillae, and the presence of mandibles. However, since its creation, many parasitic species with a wide variety of characters have been included through the years, so that many morphologically diverse species were added to this genus. Labrorostratus , with six described species, is commonly found in the coelomic cavity of Syllidae ( Odontosyllis , Syllis , Eusyllis , Pionosyllis , Grubea , Sphaerosyllis , Haplosyllis and Pseudobrania ), Nereididae (Perinereis) and Trichobranchidae (Terebellides) , and can also be found free-living, among algae ( Hernández-Alcántara and Solís-Weiss 1998).