Specimens of Isopoda: Anthuridea belonging to the genus Mesanthura, a recent record for the western Mediterranean Sea, were collected from the fouling of the harbour of Salerno (Tyrrhenian Sea, Italy) and from cryptic environments in the roadstead of the harbour of Taranto (Ionian Sea, Italy). Morphological characters and pigmentation patterns indicate that they belong to the same species whose taxonomic identity has yet to be established. Harbour fouling seems to constitute the preferential habitat of the species. At Taranto, in addition to specimens collected from fouling, two gravid females were found in dead sheaths of the endemic seagrass Posidonia oceanica. An introduced origin is suggested by several attributes of the species.
