Porcellanid crabs (Crustacea, Decapoda) inhabiting sand reefs built by Phragmatopoma lapidosa (Polychaeta Sabellariidae) at Paranapuã beach , São Vicente, SP, Brazil

The purpose of this study is to survey the porcellanid crab fauna inhabiting Phragmatopoma lapidosa sand reefs at Paranapuã Beach, São Vicente (SP), Brazil, and to assess species diversity, density and spatial distribution at this locality. Monthly samples were carried out from September/94 to August/95 in three established sampling sites along the rocky shore. Five species of Porcellanidae were recorded: Pachycheles laevidactylus, P. monilifer, Petrolisthes armatus, Pisidia brasiliensis and Megalobrachium roseum comprising 9,084 specimens. The former four species were recorded in all sampling sites while the latter ocurred only in one. The highest relative density was showed by P. laevidactylus followed by P. armatus. Remaining species were present in much lower densities, disregarding site or sampling month. In general, higher densities were registered during winter. The species, P. laevidactylus, P. monilifer and P. armatus showed an heterogeneous habitat occupation along the shore, probably reflecting different tolerance levels against salinity fluctuations