Monotygma watsoni, a minute parasitic pyramidellid gastropod is newly recorded in the Mediterranean Sea from specimens recently collected off the Israeli coastline. The species, described and illustrated, matches the three syntypes of Ceratia watsoni collected in the southern Red Sea. The characteristic protoconch and teleoconch sculpture led us to assign it to Monotygma. It is the fourteenth Erythraean alien pyramidellid species recorded in the Levantine Basin. The large populations of a great number of Erythraean aliens in the Levantine Basin may serve as reservoir hosts for pyramidellids, many of which seem to be parasitic generalists, and may be introduced to native Mediterranean hosts.
