Abstract Novorostrum decorocrus Osawa, 1998, so far only known from its type locality, Iriomote Island, Ryukyu Islands, southern Japan, is herein recorded from much farther south, Ambon Island, Indonesia. Males and females of N. decorocrus differ from each other in some morphological traits and their morphological differences are also discussed and illustrated. The female of N. decorocrus is illustrated for the first time. The present record of N. decorocrus from Indonesia lends empirical support to a previous proposition, based on the duration of 12-14 days of the planktonic period of the zoeal phase, that the distribution range of N. decorocrus could possibly be wider than known at that time.

Abstract Two species of the palaemonid genus Periclimenaeus Borradaile, 1915, P. ascidiarum Holthuis, 1951 and P. maxillulidens (Schmitt, 1936), are reported from the offshore Escalvada Island, Espírito Santo, Brazil. The location represents a new southernmost record for these species in the western Atlantic. Both species were found inside an undescribed tunicate species of Diplosoma, dwelling inside the circulatory channels, among the zooid clusters. Although P. ascidiarum is known to occur in tunicates, the finding of the rare P. maxillulidens inside an ascidian host represents the first record of this association. Illustrations for both species and a taxonomic key for the southwestern Atlantic Periclimenaeus are provided based on the present material and literature records.

Abstract Pisidia longimana (Risso, 1816) and P. bluteli (Risso, 1816), both described from Nice, France, have been considered each other’s synonyms or have been validated depending on successive taxonomic opinions. The validity of both in respect to P. longicornis (Linnaeus, 1767) has also been contradicted a number of times. The current lack of clarity in the use of the names P. longicornis, P. longimana and P. bluteli has resulted in nomenclatural instability, but also in unreliability and miscommunication as regards the available ecological and distributional information. The validity of P. bluteli and P. longimana is revisited herein based on a large number of specimens (241 males, 190 females and 33 juveniles) from many different localities. The latter species is confirmed as a junior synonym of the former, whereas P. bluteli and P. longicornis are herein considered separate species. Diagnostic characters and morphological variations are discussed and illustrated.

Abstract Porcellana paivacarvalhoi Rodrigues da Costa, 1968, described from southeastern Brazil (São Sebastião, São Paulo), is morphologically similar to the eastern Atlantic P. platycheles (Pennant, 1777), and also to the west African P. africana Chace, 1956. The synonymy between P. paivacarvalhoi and P. platycheles was proposed by previous authors without examination of any specimens of P. platycheles, nor did they considered the morphological similarities between P. paivacarvalhoi and P. africana. This synonymy has been implicitly accepted without further analysis. The recent discovery of one male and two females syntypes of P. paivacarvalhoi has prompted new investigations into the status of P. paivacarvalhoi as a junior synonym either of P. platycheles or P. africana. Porcellana paivacarvalhoi is redescribed and illustrated based upon its lectotype herein designated. It is confirmed to be a junior synonym of P. platycheles; all evidence suggests that P. africana is a distinct, separate species. All previous records of P. platycheles from the Brazilian coast are reviewed. Its presence in southeastern Brazil in the late 1960’s most probably represents an historical case of human-mediated introduction by shipping activities. Porcellana platycheles did not manage to establish itself in São Sebastião, nor has it been recorded subsequently elsewhere in Brazil.

Abstract Previously known only from Argentina and Uruguay, Anacalliax argentinensis is herein reported for the first time from Rio de Janeiro, representing the first occurrence of genus Anacalliax in the Brazilian coast and the northernmost record of the species in the Atlantic Ocean. Morphological variations on the third maxilliped and first pereopods are discussed based in our material.

Abstract The morphology of the fifth pereiopods was studied under scanning electron microscopy in ten species of porcelain crabs for chaetotaxy and setal diversity, namelly Megalobrachium pacificum, Megalobrachium roseum, Pachycheles grossimanus, Petrolisthes armatus, Petrolisthes tuberculatus, Pisidia brasiliensis, Pisidia longicornis, Polyonyx gibbesi, Porcellana platycheles and Porcellana sayana. Six setal types were identified: simple, pappose, sickle-shaped serrate, straight serrate, club-shaped and tooth-like cuspidate. Porcelain crabs can differ in the fifth pereiopod setal morphology, chaetotaxy and setal density, even among species within the same genus. The absence of sexual dimorphism of the grooming legs in porcelain crabs suggests that grooming eggs requires no particular grooming apparatus in females and that male and female are equal in grooming efficiency.

Abstract The occurrence of intersex specimens of Lissoporcellana quadrilobata (Miers, 1884), Pisidia bluteli (Risso, 1816) and Pisidia longimana (Risso, 1816) is recorded for the first time and their secondary sexual characters analyzed. Intersex specimens were collected in regions regularly affected by pollution. There is a high possibility that intersexuality in porcelain crabs is caused by environmental contamination.

Intersex specimens of Pisidia longicornis (Linnaeus, 1767) are recorded for the first time and their secondary sexual characters are analyzed. Of 145 specimens of P. longicornis examined in this study, six were identified as intersex individuals. Of these, three presented male secondary sexual characters, well-developed male gonopores and rudimentary female gonopores, whereas the other three had female secondary sexual characters, with female gonopores being more pronounced than the male ones. The present study provides the first record of intersex porcelain crabs.