This study provides the first record of the exotic invasive bivalve Isognomon bicolor for the State of Paraíba, Northeastern Brazil. It has been found to occur in at least twelve coastal reefs along the coast. We also present its first record for the State of Alagoas and new record localities for the States of Rio Grande do Norte and Pernambuco, including its occurrence in hypersaline estuaries. From these records the distribution range of I. bicolor has been expanded to the littoral region of Northeast Brazil, where this invasive species seems well established.

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Spawning ofCassis tuberosais recorded and described for the first time, based on observations carried out in the Tamandaré reefs, north-eastern Brazil. The specimen was laying over gravel substrate surrounded by macroalgae at a depth of 2 m.Cassis tuberosauses an algal frond of the genusPadinato lay its eggs. The oothecae consists of approximately 200 vasiform capsules, orange in colour. The spawn ofCassis tuberosais quite similar to that produced by its congener,Cassis madagascariensis; however,Cassis tuberosaspawns in the soft substrate provided by algal fronds whileCassis madagascariensisutilizes coarse, carbonate sand. Considering thatCassis tuberosais the target of multiple commercial purposes, to expand our knowledge about its biology could contribute towards protecting the essential habitat of reproductively active individuals.

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What do we know about Cassis tuberosa (Mollusca: Cassidae), a heavily exploited marine gastropod? ABSTRACTCassis tuberosa is a key species in reefs and sandy beaches, where it plays an essential role as a predator of sea urchins and sand dollars. Due to the beauty of its shell, it is one of the most exploited species for trade as marine souvenirs throughout its distribution in the Western Atlantic. Despite its ecological importance, there is little available information about population and biological data or the impacts of its removal from its natural habitats. Considering the economic and ecological importance of this species, this study provides a short review of existing studies and highlights research and conservation needs for this highly exploited marine gastropod.

Aim Avicennia schaeuriana is one of the six species that composes the mangrove forests of Brazil and form mangrove fringes along waterways. The mangrove-roots of the A. schaeuriana act as one of the microhabitats used by the invertebrate biodiversity of the estuarine ecosystem. The present note aimed to inventory the malacofauna associated with roots of Avicennia schaueriana of the hypersaline and inverse estuary, highlighting variations in abundance and diversity along a salinity gradient and different seasonal periods. Methods Three sampling stations were delineated along the course of the estuary. At each station 3 transects of 10 meters were placed, and for each of them 3 sample points were selected, and at each point 3 samples of roots of A. schaueriana were obtained. A total of 108 samples were stored in plastic bags containing 4% formaldehyde and subsequently passed through a screening process, with identification of the associated specimens with the lowest possible taxonomic level. Results A total of 171 specimens was recorded, belonging to 10 species, 7 families, and 9 genera of the Bivalvia and Gastropoda classes. The abundance of the specimens differed between the seasonal periods analyzed. Conclusions The highest species richness and abundance of organisms in the rainy period allows inferences about the importance of the estuarine water cycle in regulating the biodiversity of these environments. Thus, the importance of the maintenance and protection of the mangrove forests composed of A. schaueriana, as well as the need for more in-depth studies becomes evident.

We report an interaction between Octopus insularis (Octopoda, Octopodidae) and the reef fish Alphestes afer (Perciformes, Epinephelidae) and provide evidence of mimicry, camouflage and following behaviors. We observed three instances of this interaction during dives at the Pirangi reefs, Northeastern Brazil. The octopus's body color patterns indicated the type of behavior that developed while it was followed by the reef fish. These data are the first records of following behavior in A. afer and the first observation of such interaction with O. insularis in coastal reefs.