The presence of the non-native diamond lizardfish Synodus synodus off the coast of Benghazi, Libya: Implications for Mediterranean biodiversity

As one of the world’s foremost hotspots for marine bioinvasions, the Mediterranean Sea functions as a dynamic theater where both introduced aliens and naturally range-expanding neonative species are actively rewriting the region’s biodiversity narrative. Among the fishes navigating this shifting landscape, the diamond lizardfish Synodus synodus, a species of subtropical Atlantic origin, has historically remained on the periphery of the basin’s ichthyofauna, its presence long regarded as incidental and supported by little more than fragmentary or poorly substantiated records. The present study confirms the occurrence of S. synodus (Linnaeus, 1758) along the central southern coast of the Mediterranean, based on morphological examination of three specimens collected on 18 June 2025, off the coast of Benghazi, Libya. Meristic counts and morphometric measurements yielded diagnostic characters unequivocally consistent with the species. The confirmation of S. synodus in Libyan waters carries considerable ecological and zoogeographical weight, particularly when viewed against the broader backdrop of the species’ progressive range expansion throughout the Mediterranean Basin.