Résumé
This Collective article presents 18 introduced taxa in the Mediterranean Sea, belonging to seven phyla and documented at 22 new locations and seven countries spanning from the Levantine to the western Mediterranean. These records include the first country records of the African mussel Perna perna (Syria), the sea slug species complex Elysia cf. marginata-grandifolia (Cyprus), the green algae Acetabularia caliculus and the parasitic amphipod Brachyscelus rapacoides (Türkiye), the lizardfish Synodus randalli (Greece), the red algae Chondria coerulescens (Croatia) and the gastropod Pyrgulina maiae (Tunisia). Moreover, the cardinalfish Cheilodipterus novemstriatus is recorded for the first time from the Aegean Sea (Greece), the shrimp Urocaridella pulchella from the Ionian Sea (Greece) and the colonial ascidian Aplidium accarense and the polychaete Laonome triangularis from the Adriatic Sea (Italy). Regarding the expansion of non-indigenous species, this article documents the southernmost occurrence of the cornetfish Fistularia petimba in the Aegean Sea (Greece) and the westernmost occurrence of the lizardfish Saurida lessepsianus in the Mediterranean (Greece). Moreover, it includes information on the continued spread of the zooxanthellate coral Oculina patagonica in Türkiye, as well as the further expansion of the crab Dyspanopeus sayi and the colonial ascidian Polyandrocarpa zorritensis in Italy. Finally, the first Mediterranean record of the sea slug Tubulophilinopsis reticulata (Tunisia), and the northernmost global record of the snapping/pistol shrimp Synalpheus africanus (Italy) are reported.