Streblosoma Sars, 1872

Santos, Andre Souza Dos, Nogueira, João Miguel De Matos, Fukuda, Marcelo Veronesi & Christoffersen, Martin Lindsey, 2010, New terebellids (Polychaeta: Terebellidae) from northeastern Brazil, Zootaxa 2389 (1), pp. 1-46 : 5

Genus Streblosoma Sars, 1872

Type species: Grymaea bairdi Malmgren, 1866 .

Diagnosis. Prostomium at base of upper lip; basal part of prostomium usually with eyespots, distal part usually forming shelf-like process from which buccal tentacles originate. Peristomium forming lips, sometimes continuing dorsally, with developed nuchal organs at border with prostomium. Lateral lobes on anterior segments absent, but segment 2 usually protruding ventrally. Zero to 3 pairs of branchiae, on segments 2–4, each with numerous simple filaments progressively tapering to tips. Notopodia beginning on segment 2, continuing for variable number of segments, with distally winged notochaetae. Neuropodia beginning on segment 5, extending until posterior body, neuropodia usually glandular, slightly raised from body wall; uncini with elongate base, dorsal button terminal or almost, prow, if present, reduced to short knob and main fang topped by few rows of secondary teeth.

Remarks. Streblosoma is a large genus, characterized by having notopodia from segment 2, bearing distally winged notochaetae, and neuropodia from segment 5. The species of this genus are distinguished mainly by: (1) the morphology of the lower lip, narrow or swollen; (2) the morphology of the branchiae, including the number of pairs of branchiae, if branchial filaments originate directly from the body wall, or from swollen, glandular areas, the number of branchial filaments on each pair, if the area of origin of branchial filaments of the first pair extends laterally beyond the first pair of notopodia or not, and if the filaments are arranged to form continuous rows across the dorsum or a medial gap is present; (3) the morphology of notochaetae, if narrowly or broadly winged; and (4) the morphology of uncini, in regards to the dental formula, position of the dorsal button, size of prow and if the uncini are arranged in straight or curved, sometimes looped rows ( Hutchings & Murray 1984; Holthe 1986; Hutchings & Glasby 1987; Nogueira et al. 2004, in press; Nogueira & Hutchings 2007).

Three species of Streblosoma have been recorded from the Brazilian coast before this study ( Amaral et al. 2006), of which S. oligobranchiatum Nogueira & Amaral, 2001 and S. porchatensis Nogueira, Garraffoni & Alves, 2004 are only known from the State of São Paulo, and S. bairdi ( Malmgren, 1866) is known from the states of Alagoas, northeastern Brazil ( Nonato & Luna 1970), and Rio de Janeiro and São Paulo, southeastern Brazil ( Rullier & Amoureux 1979; Lana 1981; Morgado & Amaral 1989; Amaral et al. 1994, among others). Prior to this study, there was no record of this genus for the State of Rio Grande do Norte.