New records of the alien polychaete worm Chaetozone corona (Polychaeta: Cirratulidae) in the Adriatic Sea

Several specimens of the alien polychaete Chaetozone corona were encountered at sites along the Italian coasts of the Adriatic Sea between 2006 and 2015, indicating its successful establishment in the area. Morphological variability between specimens from the North Adriatic and the South Adriatic was detected. Methyl Green staining patterns revealed further minor differences suggesting the presence of two slightly different populations. Chaetozone corona does not appear to be invasive in natural conditions, but it appears more abundant in polluted port sediments, what may represent the main source of introduction.