We report the first record of Eastonia rugosa in Sardinia. Living individuals and loose valves were found in proximity of the Rio Padrongianus delta, near Olbia in the north-eastern part of the island. Several alien species were found in the same area. It cannot be excluded that E. rugosa reached this locality by anthropogenic media, but the drivers (natural versus anthropogenic) of the range extension of this species still have to be clearly identified. This issue is very important to understand to what extent E. rugosa is adequate as a descriptor of the Mediterranean Sea ‘tropicalization' as suggested in recent monitoring programmes.
