Museu de Zoologia

Two new species of Odontosyllis were found in samples collected mainly on rocky shores off the states of São Paulo (SE Brazil) and Paraíba (NE Brazil). Odontosyllis aracaensis sp. nov., and O. guarauensis sp. nov., are herein described and compared to their most similar congeners. A key for the species found in Brazil is provided, and relevant morphological characters of similar species of the genus, based on falcigers morphology, are summarized and compared with those of the newly described species. The current state of knowledge on the genus is briefly discussed.

ABSTRACT Eupanthalis rudipalpa Amaral & Nonato, 1984 was described based on three incomplete, colorless specimens and has not been reported since its original description; the epithet rudipalpa means “hirsute palps”, a characteristic that separates it from other congeneric species. Eupanthalis McIntosh, 1876 and Euarche Ehlers, 1887, and their respective type species, E. kinbergi McIntosh, 1876 and E. tubifex Ehlers, 1887, were considered synonyms (E. rudipalpa as a junior synonym of E. tubifex, a cosmopolitan species) by some authors, because both have sessile eyes and two or three antennae. Nonetheless, these two genera are, in fact, distinct. Their type species can clearly be separated using some prostomial features. We provide an emended diagnosis of Euarche, and re-instate E. rudipalpa, redescribing it based on a Brazilian specimen (original type specimens lost). Illustrations showing body pigmentation pattern and a key to all species of Eupanthalis are also provided.

We present herein the first records for Amblyosyllis, Eusyllis and Perkinsyllis from northeastern Brazil, describing and illustrating Amblyosyllis sp., Eusyllis kupfferi and E. lamelligera, which are compared to the morphologically most similar congeners; a brief diagnosis is provided for Eusyllis nonatoi, Odontosyllis aracaensis, O. guarauensis, O. guillermoi and Perkinsyllis biota, described from southeastern Brazil. In addition, a new species of Odontosyllis is described, O. brevichaetosa sp. n., characterized by having short, bidentate falciger blades with inverted dorso-ventral gradation in length, and shafts of ventralmost falcigers from midbody parapodia onwards subdistally inflated, with sigmoid tip. A key for the valid Brazilian species of Odontosyllis is provided. Finally, this is also the first account of the genus Streptodonta for the South Atlantic, with the description of S. fauchaldi sp. n., characterized by a distinct distribution pattern of cilia along body, presence of spiniger-like chaetae, and morphology of falciger blades.