Annellus Tempère in Tempère & H. Peragallo, 1908 † (extant flag source)
Archaeolithothamnium Rothpletz, 1891 accepted as Archaeolithothamnion Rothpletz ex Foslie, 1898 (extant flag source)
Cymatosiraceae Hasle, von Stosch & Syvertsen, 1983 (extant flag source)
Discolithus Huxley, 1868 accepted as Discolithus Kamptner ex Deflandre in Piveteau, 1952 † accepted as Pontosphaera Lohmann, 1902 (extant flag source)
Goniothecium Ehrenberg, 1843 † (extant flag source)
Mediaria Sheshukova-Poretzkaya, 1962 † (extant flag source)
Paraliaceae Crawford, 1988 (extant flag source)
Polyphysaceae Kützing, 1843 (extant flag source)
Pseudopyxilla Forti, 1909 † (extant flag source)
Rouxia J. Brun & Héribaud in Héribaud, 1893 † (extant flag source)
Sporolithaceae Verheij, 1993 (extant flag source)
Stephanogonia Ehrenberg, 1844 † (extant flag source)
Thalassionemataceae Round, 1990 (extant flag source)
Trochosira Kitton, 1871 † (extant flag source)