On a trip to the mainland: occasional records of the rocky crab Grapsus grapsus (Linnaeus, 1758) (Decapoda: Grapsidae) on the Brazilian coast

Abstract The Sally lightfoot crab, Grapsus grapsus (Linnaeus, 1758), is distributed along the Eastern Pacific coast and along the Western Atlantic coast, from the Gulf of Mexico to the Southwestern Atlantic. In Brazil, the only established populations are found on the Brazilian oceanic islands, although two previous records (1901 and 1966) reported the presence of individuals on the continental coast. Here, we report new records of the Sally lightfoot crab on the coast of the states of Espírito Santo and Rio Grande do Norte, southeastern and northeastern Brazil, respectively. We also discuss three main hypotheses that could explain occasional records (1901, 1966, 2005, and 2020) of single individuals on the mainland: rafting events associated with flotsam and debris carried by oceanic currents; hitchhiking on vessels and fishing boats navigating routes from the Brazilian oceanic islands to the mainland; and stochastic settlement through larval dispersal.