Rapid expansion of a Lessepsian migrant crab, Gonioinfradens giardi (Crustacea, Brachyura, Portunidae), in the Ionian Sea: New records and early evidence of establishment

The portunid crab, Gonioinfradens giardi (Nobili, 1905), native to the Red Sea and the Indian Ocean, is one of the recent alien decapods expanding in the Mediterranean Sea. Following the first confirmed Italian record from Portopalo di Capo Passero in November 2025, here we documented 11 additional specimens collected between November 2025 and January 2026 from the Ionian coast of Sicily. These repeated occurrences over a short time period and within a relatively small area strongly suggest that the species is no longer an occasional arrival, but at an early phase of local establishment in the central Mediterranean. These records represent the species' westernmost occurrence and highlight the need for targeted monitoring of alien portunids in the Mediterranean.