Alveoflexus firthii Hendey & Sims, 1984 † (uncertain > unassessed )
Ancoropsis eocenica Hendey & Sims, 1984 † (uncertain > unassessed )
Arcusidiscus oppositus S.Komura, 2008 †
Biddulphia abjecta Mann, 1925 (uncertain > unassessed )
Biddulphia abyssorum (uncertain > unassessed )
Biddulphia abyssorum var. abyssorum Grunow in Van Heurck, 1883 (uncertain > unassessed )
Biddulphia abyssorum var. polycistinorum ‘Pantocsek' Mills, 1933 (uncertain > unassessed )
Biddulphia abyssorum var. saratovianum (Pantocsek) F.W. Mills, 1933 accepted as Triceratium abyssorum var. saratovianum Pantocsek, 1889
Biddulphia acanthoceros Forti, 1913 (uncertain > unassessed )
Biddulphia acuta (Ehrenberg) Boyer, 1900 accepted as Triceratium acutum Ehrenberg, 1844 (1845)
Biddulphia advena VanLandingham, 1968 (uncertain > unassessed )
Biddulphia affinis (Grunow in Van Heurck) Van Heurck, 1909 accepted as Triceratium affine Grunow in Van Heurck, 1883
Biddulphia africana Leuduger-Fortmorel, 1898 (uncertain > unassessed )
Biddulphia agulhas Karsten, 1905 (uncertain > unassessed )
Biddulphia alaskiensis Mann, 1907 (uncertain > unassessed )
Biddulphia alternans (Bailey) Van Heurck, 1885 accepted as Trigonium alternans (Bailey) A.Mann, 1907 accepted as Triceratium alternans f. alternans J.W. Bailey, 1851
Biddulphia alternans var. alternans (J.W. Bailey) Van Heurck, 1885 accepted as Triceratium alternans f. alternans J.W. Bailey, 1851
Biddulphia alternans var. tenuipunctata Mereschkowsky, 1902 (uncertain > unassessed )
Biddulphia alternans var. variabilis (Brightwell) Mereschkowsky, 1900 accepted as Triceratium variable Brightwell, 1856
Biddulphia americana (Ralfs in Pritchard) Boyer, 1900 accepted as Triceratium americanum var. americanum Ralfs in Pritchard, 1861
Biddulphia amphicephala (Ehrenberg) Ralfs in Pritchard, 1861 accepted as Odontella amphicephala Ehrenberg, 1845
Biddulphia angulata Schmidt in Schmidt et al., 1888 (uncertain > unassessed )
Biddulphia antarctica (Ehrenberg) M. Peragallo, 1897 accepted as Hemiaulus antarcticus Ehrenberg, 1844
Biddulphia antarctica ‘Cleve' Mills (uncertain > unassessed )
Biddulphia antarctica f. typica ‘Meunier' VanLandingham (uncertain > unassessed )
Biddulphia antediluviana (Ehrenberg) Van Heurck, 1885
Biddulphia antediluviana ‘Azpeitia y Moros' Mills, 1911 (uncertain > unassessed )
Biddulphia antediluviana var. antediluviana (Ehrenberg) Van Heurck, 1885 accepted as Amphitetras antediluviana var. antediluviana Ehrenberg, 1840
Biddulphia antediluviana var. cruciformis ‘W. Smith' according to Mills (uncertain > unassessed )
Biddulphia antediluviana var. excavata "Adam's Collection" according to Mills (uncertain > unassessed )
Biddulphia antediluviana var. excavata Frenguelli, 1945 (uncertain > unassessed )
Biddulphia antediluviana var. minor (H. Peragallo & M. Peragallo) F.W. Mills accepted as Amphitetras antediluviana var. minor Peragallo & Peragallo, 1902
Biddulphia antediluviana var. minutum (Greville) F.W. Mills, 1933 accepted as Amphitetras minuta Greville, 1861
Biddulphia antediluviana var. nobilis “Adam's Collection” according to F.W. Mills (uncertain > unassessed )
Biddulphia antediluviana var. ornata Hendey, 1971 (uncertain > unassessed )
Biddulphia antediluviana var. pentagona (Hustedt) F.W. Mills, 1933 accepted as Triceratium antediluvianum f. pentagona Hustedt, 1930
Biddulphia antediluviana var. tesselata (Shadbolt) F.W. Mills, 1933 accepted as Amphitetras tessellata Shadbolt, 1854
Biddulphia antediluviana var. trigona (M. Peragallo in Tempère & Peragallo) F.W. Mills, 1933 accepted as Triceratium antediluvianum var. trigona M. Peragallo in Peragallo & Peragallo, 1911
Biddulphia anthropomorpha Van Heurck, 1909 (uncertain > unassessed )
Biddulphia antillarum (Cleve) Boyer, 1900 accepted as Triceratium antillarum var. antillarum Cleve, 1878
Biddulphia antiqua Truan y Luard & Witt, 1888 (uncertain > unassessed )
Biddulphia apiculata Long, Fuge & Smith, 1946 (uncertain > unassessed )
Biddulphia arctica (Brightwell) Boyer, 1901 accepted as Trigonium arcticum (Brightwell) Cleve, 1868
Biddulphia arctica f. arctica (Brightwell) Boyer, 1900 accepted as Triceratium arcticum f. arcticum Brightwell, 1853
Biddulphia arctica f. balaena (Ehrenberg) E. Jørgensen, 1905 accepted as Zygoceros balaena Ehrenberg, 1853
Biddulphia arctica f. interjecta (Schmidt in Schmidt et al.) F.W. Mills, 1933 accepted as Triceratium interjectum f. interjectum Schmidt in Schmidt et al., 1891
Biddulphia arctica f. peragalli ‘Schmidt' Van Heurck accepted as Triceratium peragallii f. peragallii Brun in Schmidt et al., 1891
Biddulphia arctica var. antarctica (Cleve & Grunow) F.W. Mills, 1933 accepted as Triceratium arcticum var. antarctica Grunow
Biddulphia arctica var. arctica (Brightwell) E. Jørgensen, 1905 accepted as Triceratium arcticum f. arcticum Brightwell, 1853
Biddulphia arctica var. californica (Grunow in Schmidt et al.) Boyer, 1900 accepted as Triceratium arcticum f. californica Grunow in Schmidt et al., 1882
Biddulphia arctica var. campeachiana (Grunow in Van Heurck) Boyer, 1900 accepted as Triceratium arcticum f. campechiana Grunow in Van Heurck, 1883
Biddulphia arctica var. japonica (Grunow in Schmidt et al.) F.W. Mills, 1933 accepted as Triceratium arcticum var. japonica Grunow in Schmidt et al., 1882
Biddulphia arctica var. kerguelensis (Grunow in Cleve & Grunow) Boyer, 1900 accepted as Triceratium arcticum var. kerguelense Grunow in Cleve & Grunow, 1880
Biddulphia arctica var. montereyi (Brightwell) Boyer, 1900 accepted as Triceratium montereyi f. montereyi Brightwell, 1853
Biddulphia arctica var. neapolitana (Grunow in Cleve & Grunow) F.W. Mills, 1933 accepted as Triceratium arcticum var. neapolitana Grunow in Cleve & Grunow, 1880
Biddulphia arctica var. pentagona Boyer, 1900 (uncertain > unassessed )
Biddulphia arctica var. quadrangularis (Greville) Boyer, 1900 accepted as Triceratium quadrangulare Greville, 1865
Biddulphia arctica var. quinquelobatum (Greville) F.W. Mills, 1933 accepted as Triceratium quinquelobatum Greville, 1866
Biddulphia arctica var. robusta (Truan y Luard & Witt) F.W. Mills, 1933 accepted as Triceratium arcticum var. robusta Truan y Luard & Witt, 1888
Biddulphia arctica var. samoensis (Cleve & Grunow) F.W. Mills, 1933 accepted as Triceratium arcticum var. samoensis Grunow
Biddulphia arctica var. sexangulata Boyer, 1900 (uncertain > unassessed )
Biddulphia arctica var. spitzbergensis (Grunow in Cleve & Grunow) F.W. Mills, 1933 accepted as Triceratium arcticum var. spitzbergensis Grunow in Cleve & Grunow, 1880
Biddulphia arctica var. tetragona (Grunow) Mereschkowsky, 1901 accepted as Triceratium arcticum var. tetragona Grunow in Cleve & Grunow, 1880
Biddulphia arcuata (Shadbolt) F.W. Mills, 1933 accepted as Triceratium arcuatum Shadbolt, 1854
Biddulphia areolata Hajós, 1968 (uncertain > unassessed )
Biddulphia argus Boyer, 1898 (uncertain > unassessed )
Biddulphia armata Leuduger-Fortmorel, 1879 (uncertain > unassessed )
Biddulphia astrolabensis Hendey, 1937 (uncertain > unassessed )
Biddulphia auliscoformis Strelnikova, 1964 (uncertain > unassessed )
Biddulphia aurita (Lyngbye) Brébisson, 1838 accepted as Odontella aurita (Lyngbye) C.Agardh, 1832
Biddulphia aurita var. aurita (Lyngbye) Brébisson, 1838 accepted as Diatoma auritum Lyngbye, 1819
Biddulphia aurita var. minima Grunow in Van Heurck, 1882 accepted as Ralfsiella minima (Grunow in Van Heurck) P.A. Sims & D. M. Williams in Sims et al., 2018
Biddulphia aurita var. minuscula Grunow in Van Heurck, 1882 (uncertain > unassessed )
Biddulphia aurita var. obtusa (Kützing) Hustedt, 1930 accepted as Odontella obtusa Kützing, 1844
Biddulphia aurita var. orientalis Mereschkowsky, 1902 (uncertain > unassessed )
Biddulphia aurita var. polyspina Kisselev, 1931 (uncertain > unassessed )
Biddulphia australis Montagne, 1842 (uncertain > unassessed )
Biddulphia azorica J.Pavillard, 1908 (uncertain > unassessed )
Biddulphia bailey W. Smith, 1856 accepted as Biddulphia mobiliensis (J.W.Bailey) Grunow, 1882 accepted as Trieres mobiliensis (J.W.Bailey) Ashworth & E.C.Theriot in Ashworth, Nakov & E.C.Theiriot, 2013
Biddulphia baileyii W. Smith, 1856 (uncertain > unassessed )
Biddulphia balaena (Ehrenberg) T.Brightwell accepted as Zygoceros balaena Ehrenberg, 1853
Biddulphia balaena f. campechiana Grunow in Van Heurck, 1883 (uncertain > unassessed )
Biddulphia balaena var. arctica Peragallo & Peragallo, 1902 (uncertain > unassessed )
Biddulphia balaena var. balaena (Ehrenberg) Brightwell, 1859 accepted as Zygoceros balaena Ehrenberg, 1853
Biddulphia baldjikii Girard (uncertain > unassessed )
Biddulphia balearica (Cleve & Grunow) A.Mann, 1925 accepted as Triceratium balearicum f. balearicum Cleve & Grunow in Cleve, 1881
Biddulphia baltzoi Hanna, 1970 (uncertain > unassessed )
Biddulphia barbadensis Greville, 1866 (uncertain > unassessed )
Biddulphia belgicae M.Peragallo
Biddulphia belgicae var. belgicae M. Peragallo, 1921 (uncertain > unassessed )
Biddulphia belgicae var. lata M. Peragallo, 1921 (uncertain > unassessed )
Biddulphia bicorne Cleve, 1878 (uncertain > unassessed )
Biddulphia bicornis Cleve, 1878 (uncertain > unassessed )
Biddulphia biddulphiana (J.E.Smith) Boyer, 1900
Biddulphia biddulphiana var. abnormis Boyer, 1927 (uncertain > unassessed )
Biddulphia biddulphiana var. biddulphiana (J.E. Smith) Boyer, 1900 (uncertain > unassessed )
Biddulphia bifasciata Wigand, 1860 (uncertain > unassessed )
Biddulphia bifenestra Brun, 1896 (uncertain > unassessed )
Biddulphia bipons ‘Ehrenberg' Mills, 1933 (uncertain > unassessed )
Biddulphia biquadrata (Janisch in Schmidt et al.) Boyer, 1900 accepted as Triceratium biquadratum Janisch, 1886