This study reviews all European species belonging to the filiferan families Bougainvilliidae, Cytaeididae, Rathkeidae, and Pandeidae. Updated diagnoses for the families and genera are provided and taxonomic problems solved or at least outlined. Lizzia blondina is removed from the Bougainvilliidae and transferred to the Rathkeidae based on results from 16S sequence data. Dysmorphosa minuta Mayer, 1900 is regarded as a synonym of Lizzia blondina; morphological and molecular evidence is provided. Cytaeis minima Trinci, 1903, formerly included in the Hydractiniidae, is transferred to a new genus Podocorynoides and included in the Rathkeidae as Podocorynoides minima (Trinci, 1903). Perigonimus nanellus Stechow, 1919 belongs to the genus Dicoryne and is likely a synonym of Dicoryne conybearei (Allman, 1864). Perigonimus nudus Stechow, 1919 is recognized as a new synonym of Eirene
viridula (Péron & Lesueur, 1810). The Mediterranean records of Rhizorhagium
michaeli and R. arenosum are most likely based on misidentifications
of Pachycordyle pusilla (Motz-Kossowska, 1905). Annatiara
lempersi Bleeker & van der Spoel, 1988 is a synonym of Annatiara affinis
(Hartlaub, 1914).
