Apoglossum gregarium (Delesseriaceae, Rhodophyta) from Greece: a new record for the eastern Mediterranean Sea

Abstract Apoglossum gregarium, a minute deep-water red alga considered an alien in the Mediterranean Sea, was previously known only from the western basin. The present paper reports A. gregarium for the first time off Greece, in the eastern Mediterranean basin. It was found on artificial substrata at 50 m depth in the southeastern Ionian Sea. The Greek specimens were identical to previous Mediterranean descriptions. Moreover, the Greek habitat is the deepest ever recorded for the species. Associated flora as well as biogeographical data are also provided. Based on its worldwide distribution, the possibility that A. gregarium is native to the Mediterranean Sea should not be ruled out.