First record of the nudibranch Elysia gordanae T. E. Thompson & Jaklin, 1988 (Gastropoda: Plakobranchidae) in Bosnia and Herzegovina

Heterobranch sea slugs represent one of the most diverse groups of marine gastropods in the Mediterranean Sea; however, their diversity and distribution along the short coastline of Bosnia and Herzegovina remain insufficiently documented. In this study, we report the first confirmed record of the sacoglossan nudibranch Elysia gordanae T. E. Thompson & Jaklin, 1988 from the marine waters of Bosnia and Herzegovina. A single specimen was observed and collected in the intertidal zone of Neum Bay during field surveys conducted in August 2023. Morphological characteristics correspond well with published descriptions of the species. This finding represents the easternmost confirmed record of E. gordanae in the Adriatic Sea to date and contributes to the growing knowledge of heterobranch diversity in Bosnia and Herzegovina, highlighting the need for continued systematic surveys of its poorly explored marine habitats.