Accepted by P. Hutchings: 17 Mar. 2016; published: 20 Apr. 2016 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2016 Magnolia Press Zootaxa 4105 (2): 145–158 http://www.mapress.com/j/zt/ Article 145 http://doi.org/10.11646/zootaxa.4105.2.3 http://zoobank.org/urn:lsid:zoobank.org:pub:B77497BD-FF55-4097-A76B-AFD24D99E9B6 Orbinia (Polychaeta: Orbiniidae) from the Brazilian coast: two new species and two new records LUCIANA SANCHES DOURADO LEÃO 1 & CINTHYA SIMONE GOMES SANTOS 1,2 Programa de Pós-Graduação em Biologia Marinha e Ambientes Costeiros, Universidade Federal Fluminense, Instituto de Biologia, Outeiro de São João Batista, s/n Centro, CEP: 24020-141, Niterói, Rio de Janeiro, Brazil Universidade Federal Fluminense, Instituto de Biologia, Departamento de Biologia Marinha, Outeiro de São João Batista, s/n Cen- tro, CEP: 24020-141, Niterói, Rio de Janeiro, Brazil 1 Corresponding author. E-mail: douradoleao@uol.com.br Abstract Representatives of the Family Orbiniidae are very common in marine sediments and are found in both shallow and deep waters. Currently, 26 species and 10 genera have been recorded along the Brazilian coast. The specimens examined in this study were collected at depths ranging from 25 to 400 m in the Campos Basin (20–24ºS; 39–42ºW), Rio de Janeiro, in the summer and winter of 2008 and 2009. We describe two new species, Orbinia sagitta n. sp. and Orbinia camposiensis n. sp., and record the occurrences of Orbinia johnsoni (Moore, 1909), which was originally described in California, and Or- binia oligopapillata (López, Cladera & San Martin, 2006), which was previously described from the Pacific coasts of Pan- ama. We provide a key for all the species of Orbinia recorded in the Campos Basin. Palavras chave: taxonomy, Orbinia sagitta, Orbinia camposiensis, Orbinia johnsoni, Orbinia oligopapillata Introduction The Family Orbiniidae includes deposit-feeding species that are common in marine sediments and are found from shallow to deep waters in different latitudes (Rouse & Pleijel, 2001; Lopez et al. 2003; Blake, 2000; Solís-Weiss et al. 2009). Few taxonomic studies on this family have been conducted, with the most important revision having been performed by Hartman (1957). Contributions were also made by Day (1973, 1977), Mackie (1987) and Solís-Weiss & Fauchald (1989). The family contains 150 valid species in 19 genera. Formerly included in the subclass Errantia (Grube 1850; Benham 1896), nowadays it is grouped in the Sedentaria because of affinities with others families. Blake (2000) performed a brief revision of the family in which a new partition into subfamilies was proposed, and some genera were erected or re-erected from subgeneric status. Nevertheless, according to López et al. (2006), the systematics of the family remains unclear and, in some cases, the boundaries between genera are obscure, resulting in some closely-related species having been described within different genera. Orbiniids exhibit an elongated body divided into two regions; a shorter, more muscular and stout thorax, and a longer and more fragile abdomen. The prostomium is devoid of any sensorial appendages and may be pointed, as in Scoloplos (Blainville 1828), or wide, rounded and robust, as in Naineris (Blainville 1828). A single pair of small eyes may be present. The pharynx is short and eversible. The peristomium has one or two rings. Branchiae are present in most genera, but are absent in some species such as Leitoscoloplos abranchiatus (Hartman 1967). When present, they are on the mid-dorsal region from the thorax to the abdomen. The notopodia are usually unilobate, occasionally bifurcated, and the neuropodia are usually bilobate. Parapodia are lateral in the thorax and displaced to the dorsal region along the abdomen (Blake, 1996; Rouse & Pleijel, 2001). Crenulated capillaries chaetae are typical and may or may not be accompanied by uncinate hooks in the thorax. In the abdomen, it is possible to find crenulated, furcated and flail-tipped chaetae. The shape of the prostomium, number of thoracic chaetigers, position