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 Ophelia bicornis Savigny in Lamarck, 1818 Ophelia bicornis Savigny in Lamarck, 1818 | Ophelia radiata (Delle Chiaje, 1828) Notes Species complex with a confused taxonomic history. Originally described from the Gulf of Naples. Fauvel (1927) considered Ophelia bicornis and Ophelia radiata as distinct based on the number of gill pairs ( Ophelia radiata : 14 pairs; Ophelia bicornis : 15 pairs) and geographic distribution. However, both species and intermediate forms (with 14 gill pairs on one side and 15 on the other) have been found to co-occur by Britton-Davidian and Amoureux (1982) , who also found genetic differences between the two forms in an Atlantic population, with asymmetric specimens belonging to either of the two genetic variants. Based on these findings, the authors consider the species distinct. However, they were not able to assign Mediterranean specimens to either of the two Atlantic forms. Maltagliati et al. (2005) consider the results inconclusive and refer to the complex as Ophelia bicornis sensu lato. Parapar (2012) studied individuals of both Ophelia radiata and Ophelia bicornis from the collections of the Natural History Museums in Copenhagen and Madrid and could not find any differences apart from the number of gill pairs - a character which he considered too unreliable for discrimination.