1 Submitted on October 4, 2002. Accepted on November 11, 2003. 2 Museu Nacional/UFRJ, Departamento de Invertebrados. Quinta da Boa Vista, São Cristóvão, 20940-040, Rio de Janeiro, RJ, Brasil. Current address: Biozentrum Grindel und Zoologisches Museum, Universität Hamburg. Martin-Luther-King Platz 3, 20146, Hamburg, Germany. E-mail: snbrandao@terra.com.br. Arquivos do Museu Nacional, Rio de Janeiro, v.62, n.2, p.151-172, abr./jun.2004 ISSN 0365-4508 BRAZILIAN DEEP-SEA MACROCYPRIDIDAE MÜLLER, 1912 (CRUSTACEA, OSTRACODA, MACROCYPRIDOIDEA) 1 (With 13 figures) SIMONE N. BRANDÃO 2 ABSTRACT: Ten species of macrocypridids, included in five genera, had been previously recorded from Brazilian deep-sea. In this study, six samples with Macrocyprididae Müller, 1912 collected from eastern Brazilian continental slope were studied, and eight species were recorded: Macropyxis adrecta Maddocks, 1990; Macropyxis cf. adunca Maddocks, 1990; Macropyxis amanda Maddocks, 1990; Macropyxis bathyalensis (Hulings, 1967); Macropyxis similis (Brady, 1880); Macrosarisa sp.1, Macroscapha aff. inaequata Maddocks, 1990; Macroscapha sp.1. Two species, Macropyxis adrecta and Macropyxis amanda, are here recorded for the first time from the Western Atlantic. Macropyxis bathyalensis is recorded for the first time from the Southern Atlantic. Macropyxis similis, previously recorded from the eastern Brazilian continental slope, has its geographic range extended southwards. A total of nine named species and six unnamed species of Macrocyprididae are now known from the Brazilian deep-sea. The known distribution of these species is rather punctual. Additional sampling over the continental slope and the abyssal plain off Brazil probably will enlarge the number of species recorded from this area and will clarify their general distribution patterns. Key words: Macrocyprididae, Ostracoda, Crustacea, deep-sea, Brazil. RESUMO: Macrocyprididae Müller, 1912 (Crustacea, Ostracoda, Macrocypridoidea) em águas profundas ao largo do Brasil. Dez espécies de macrocipridídeos, incluídos em cinco gêneros, foram previamente registrados para águas profundas ao largo do Brasil. Neste estudo, foram analisadas seis amostras de Macrocyprididae coletadas do talude continental leste brasileiro, sendo registradas oito espécies: Macropyxis adrecta Maddocks, 1990; Macropyxis cf. adunca Maddocks, 1990; Macropyxis amanda Maddocks, 1990; Macropyxis bathyalensis (Hulings, 1967); Macropyxis similis (Brady, 1880); Macrosarisa sp.1, Macroscapha aff. inaequata Maddocks, 1990; Macroscapha sp.1. Duas espécies, Macropyxis adrecta e Macropyxis amanda, são registradas pela primeira vez para o Atlântico Ocidental. Macropyxis bathyalensis é registrada pela primeira vez para o Atlântico Sul. Macropyxis similis, previamente registrada para o talude continental leste brasileiro, tem sua distribuição geográfica estendida para o sul. Depois deste estudo, um total de nove espécies nomeadas e seis espécies não nomeadas de Macrocyprididae estão registradas para águas profundas ao largo do Brasil. A distribuição dessas espécies é pontual. Novas amostragens sobre o talude continental e a planície abissal ao largo do Brasil provavelmente aumentarão o número de espécies registradas para essas regiões e elucidará os padrões gerais de distribuição. Palavras-chave: Macrocyprididae, Ostracoda, Crustacea, mar profundo, Brasil. INTRODUCTION The family Macrocyprididae includes approximately 140 species in eight genera: Macrocypris Brady, 1868; Macrocyprina Triebel, 1960; Macropyxis Maddocks, 1990; Macrosarisa Maddocks, 1990; Macroscapha Maddocks, 1990; Macrocypria Sars, 1923; Macrocyprissa Triebel, 1960; and Macromckenziea Maddocks, 1990. The first five genera have been recorded from Brazil. Three named species of Macrocyprina Triebel, 1960 and two unnamed species were previously recorded from Brazilian waters (DIAS-BRITO, MOURA & WÜRDIG, 1988; COIMBRA, RAMOS & SANGUINETTI, 1992; COIMBRA et al. , 1999; BRANDÃO, in press). All of these species were recorded from the continental shelf, and one of them, Macrocyprina sp.1 was also recorded from the shallow continental slope, deepest record of 223m (Figs.1, 13, Tab.1) (COIMBRA, RAMOS & SANGUINETTI, 1992; COIMBRA, 1995; COIMBRA et al., 1999). The records of the other four genera known from Brazil exclusively comprise specimens collected from the deep-sea (Figs.1-3, 13, Tab.1). These records are