Abstract Heterobranch sea slugs (Gastropoda) present reduction, internalization, or absence of shell, and include more than 6,000 described species. Approximately 250 species are recorded from Brazil but only 14 had been previously recorded from Rio Grande do Norte, on the Brazilian northeastern coast. As a result of different expeditions conducted between 2008 and 2020, 41 species were collected and identified. Among them, five species were recorded for the first time from the South Atlantic Ocean: Chelidonura hirundinina (Quoy & Gaimard, 1833); Sclerodoris prea (Ev. Marcus & Er. Marcus, 1967); Thuridilla malaquita Ortea & Buske, 2014; Berthella nebula Ghanimi, Schrödl, Goddard, Ballesteros, Gosliner & Valdés, 2020 and Berthella vialactea Ghanimi, Schrödl, Goddard, Ballesteros, Gosliner & Valdés, 2020. Thirty-six species are recorded for the first time from Rio Grande do Norte. The present survey expands the knowledge of the diversity of sea slugs from Brazil and supports the hypothesis of similarity between the heterobranch sea slug fauna from the northeastern Brazil and the Caribbean Sea.

O imposex caracteriza-se pelo surgimento de estruturas sexuais masculinas, em fêmeas de gastrópodes. Cerca de 120 espécies de moluscos que exibem o fenômeno quando expostas a contaminação por compostos orgânicos de estanho tais como o Tributilestanho (TBT) e o Trifenilestanho (TPT). Esses compostos são utilizados, sobretudo em embarcações, no intuito de evitar a bioincrustração que danifica as embarcações e eleva os custos das viagens marítimas. No Brasil se conhecem 5 espécies de moluscos gastrópodes que manifestam imposex, são elas: Stramonita haemastoma, Stramonita rustica, Leucozonia nassa, Cymathium parthenopeum e Olivancillaria vesica. No Nordeste, monitoramentos da contaminação por organoestânicos foram realizados utilizando o imposex em gastrópodes como biomarcador. O presente estudo tem por objetivo notificar a primeira ocorrência de imposex na espécie endêmica do Nordeste brasileiro, Voluta ebraea. De um total de 11 animais observados, duas fêmeas apresentaram imposex, provenientes da Praia do Pacheco no litoral do Ceará. Observou-se nesses indivíduos a presença de glândula de cápsulas, ovidutos e receptáculo seminal concomitantemente ao pênis o que caracteriza o imposex. Como o imposex só se manifesta em moluscos expostos a compostos organoestânicos tipicamente encontrados em portos, marinas, estaleiros e locais com grande fluxo de embarcações atribui-se a origem dessa contaminação provavelmente a um estaleiro localizado nas proximidades da área de coleta.

Imposex is characterized by the development of masculine sexual organs in neogastropod females. Almost 120 mollusk species are known to present imposex when exposed to organic tin compounds as tributyltin (TBT) and triphenyltin (TPT). These compounds are used as biocide agents in antifouling paints to prevent the incrustations on boats. Five gastropod species are known to present imposex in Brazil: Stramonita haemastoma, Stramonita rustica, Leucozonia nassa, Cymathium parthenopeum and Olivancillaria vesica. This paper reports the first record of imposex observed in the endemic gastropod Voluta ebraea from Pacheco Beach, Northeast Brazil. Animals presenting imposex had regular female reproductive organs (capsule gland, oviduct and sperm-ingesting gland) and an abnormal penis. As imposex occurs in mollusks exposed to organotin compounds typically found at harbors, marinas, shipyards and areas with high shipping activities, probably contamination of Pacheco Beach is a consequence of a shipyard activity located in the nearest areas.