Vibrio splendidus clade associated with a disease affecting Paracentrotus lividus (Lamarck, 1816) in Sardinia (Western Mediterranean)

[Display omitted] •Sea urchins are an important commercial species.•Sea Urchin Bald Disease is often reported but scientific studies are scarce.•The Vibrio splendidus clade is isolated in all the diseased animals.•Monitoring studies needed and multidisciplinary approaches advised. This work reports for the first time the so-called bald sea urchin disease of the populations of Paracentrotus lividus in Sardinia (Italy). Following the disease occurrence reported by local fishermen of about 35% on the collected specimens for commercial purpose, the phenomenon was evaluated in two areas. Animals displayed external lesions represented by loss of spines and greenish/brownish skeleton patches. Microscopy of exoskeleton and tube feet showed haemocytosis with associated bacteria; gut and intestine histopathology revealed inflammatory lesions of different type and intensity. Microbiological and molecular analysis revealed the presence of the strains belonging to the Vibrio splendidus clade. Due to the important ecological role of Paracentrotus lividus in the Mediterranean Sea, this report represents a wake-up call for the entire basin worth of further insights.