First record of a hagfish anchored to a living bottlenose dolphin in the Mediterranean Sea

An unusual observation of a hagfish ( Myxine glutinosa ) anchored to a living bottlenose dolphin ( Tursiops truncatus ) was documented in an encounter with a group of about 80 dolphins during an ongoing long-term research program on cetaceans in the central Mediterranean Sea, Italy. The body of the hagfish was observed extruding from the blowhole of the bottlenose dolphin showing a stereotypical surfacing–breathing pattern. The observation lasted 2h; photo-identification, acoustic, and behavioral data were collected. Succorant behaviors (i.e., “standing by”) from conspecifics and overlapping vocalizations during social phases were recorded. The dolphin was encountered again after 1 month in the same area without the hagfish, apparently in healthy conditions.