uncertain > nomen dubium (Fabricius' (1823) description is the only existing one. It does not allow further identification, hence the name is best to be considered nomen oblitum.)
(of)Fabricius, O. (1826). Fortsaettelse of nye zoologiske bidrag. 6. Nogle lidet bekjendte og tildeels nye Flad-Orme (Planariae). <em>Det Kongelige Danske Videnskabernes Selskabs naturvidenskabelige og mathematiske afhandlinger.</em> Ser. 4(2): 16-35/ With three plates. (In Danish).[details]
Tyler, S., Artois, T.; Schilling, S.; Hooge, M.; Bush, L.F. (eds) (2006-2025). World List of turbellarian worms: Acoelomorpha, Catenulida, Rhabditophora. Polycystis leucophraeus (Fabricius, 1826) Graff, 1905. Accessed through: Costello, M.J.; Bouchet, P.; Boxshall, G.; Arvanitidis, C.; Appeltans, W. (2025) European Register of Marine Species at: http://www.marbef.org//www.marbef.org/data/aphia.php?p=taxdetails&id=143206 on 2026-10-11
Costello, M.J.; Bouchet, P.; Boxshall, G.; Arvanitidis, C.; Appeltans, W. (2026). European Register of Marine Species. Polycystis leucophraeus (Fabricius, 1826) Graff, 1905. Accessed at: https://vliz.be/vmdcdata/narms/narms.php?p=taxdetails&id=143206 on 2026-10-11
original description(of)Fabricius, O. (1826). Fortsaettelse of nye zoologiske bidrag. 6. Nogle lidet bekjendte og tildeels nye Flad-Orme (Planariae). <em>Det Kongelige Danske Videnskabernes Selskabs naturvidenskabelige og mathematiske afhandlinger.</em> Ser. 4(2): 16-35/ With three plates. (In Danish).[details]
basis of recordFaubel, A.; Noreña, C. (2001). Turbellaria, <B><I>in</I></B>: Costello, M.J. <i>et al.</i> (Ed.) (2001). <i>European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Collection Patrimoines Naturels,</i> 50: pp. 123-136 (look up in IMIS) [details] Available for editors
new combination referenceGraff, L. von. (1905). Marine Turbellarien Orotavas und der Küsten Europas. II. Rhabdocoela. <em>Zeitschrift fur wissenschaftliche Zoologie.</em> 83: 68-150. With 5 plates., available online athttps://www.biodiversitylibrary.org/page/43242488[details]
Present Inaccurate Introduced: alien Containing type locality