First occurrence of <i>Bonnierilla similis</i> Illg and Dudley, 1961 (Copepoda: notodelphyidae) in the central Mediterranean Sea

Under a plan or monitoring the fouling community in Italian marinas, we report a new host and locality for the cyclopoid copepod Bonnierilla similis, found in the branchial sac of the ascidian Styela plicata along the Sicilian coast (southern Italy), in the central Mediterranean Sea. Bonnierilla similis was originally described from the ascidian Pyura squamulosa along the western Mediterranean coast of France, near Perpignan; until now, this copepod had not been documented in any other Mediterranean localities. In this study, 10 of 14 S. plicata specimens from the Palermo marina site were infected (71% prevalence); while in the Trapani marina site all the collected S. plicata specimens were uninfected. Given that S. plicata has been extensively sampled at the Sicilian site Palermo marina in the past and, until now, had never been found to host copepods, it is possible that the species has recently expanded its range into this region. To support future taxonomic identifications, the first COI sequence data was generated here for B. similis.