Ecology and distribution of the Mediterranean Dondice trainitoi Furfaro and Mariottini, 2020 (Mollusca: Nudibranchia)

During scientific technical dives in a marine animal forest (MAF) environment, the nudibranch Dondice trainitoi Furfaro & Mariottini 2020 was recorded on a rocky bottom at 50 m depth in the Salento Peninsula, Southern Italy, Eastern Mediterranean Sea. Further in situ explorations and broad bibliographic research within both the scientific and grey literature revealed that D. trainitoi is widely distributed across the Mediterranean Sea, despite what was previously known. Herein are the first records for the Adriatic Sea and the Apulia region of Italy, together with the deepest record of this species. An analysis of collected samples and both in situ and laboratory photographs of the hydrozoan colonies associated with D. trainitoi revealed its ecology and trophic behaviour; we conclude that the hydrozoan Obelia bidentata Clark, 1875 is its preferred prey, but that it also feeds on the athecate hydroid Eudendrium glomeratum Picard, 1952. These findings shed some light on the little-known ecology and distribution, on both a geographical and a bathymetric scale, of this species, which are fundamental to increasing knowledge on Mediterranean biodiversity and its ecosystem functions.