Polychaetes of Greece: an updated and annotated checklist Author Faulwetter, Sarah Author Simboura, Nomiki Author Katsiaras, Nikolaos Author Chatzigeorgiou, Giorgos Author Arvanitidis, Christos text Biodiversity Data Journal 2017 5 20997 20997 http://dx.doi.org/10.3897/BDJ.5.e20997 journal article http://dx.doi.org/10.3897/BDJ.5.e20997 1314-2828--20997 Hydroides norvegica Gunnerus, 1768 Notes Zibrowius (1971) shows that the non-native species Hydroides elegans (Haswell, 1883) has replaced Hydroides norvegica in harbour fouling communities of the Mediterranean and that Hydroides norvegica is restricted to deeper waters. ten Hove and Kupriyanova (2009) suggest that all (sub)tropical records of Hydroides norvegica should be attributed to Hydroides elegans . In Greece, Hydroides norvegica has been reported both from harbour and shallow coastal communities as well as from deep waters below 500 m (e.g. Tselepides 1992 ). Its presence in the port of Heraklion and other Mediterranean ports has been recently confirmed ( Ulman et al. 2017 ).