• Abedinium dasypus (Cachon & Cachon-Enjumet) Loeblich Jr & Loeblich III, 1966
• Abratopdinium cardioforme S.Mao & B.A.R.Mohr †
• Abratopdinium kerguelense S.Mao & B.A.R.Mohr †
• Acanthaulax acanthosphaera (Sarjeant) Sarjeant †
• Acanthaulax aceras (Eisenack) Stover & Evitt (uncertain)
• Acanthaulax aculeata (Klement) Stover & Evitt (uncertain)
• Acanthaulax angulosa (Gitmez) Stover & Evitt (uncertain)
• Acanthaulax spinosissima (Deflandre) Sarjeant (uncertain)
• Acanthaulax venusta (Klement) Sarjeant (uncertain)
• Acanthodinium caryophyllum Kofoid, 1907
• Acanthodinium spinosum Kofoid, 1907 accepted as Cladopyxis spinosa (Kofoid) Schiller
• Acanthogonyaulax acanthosphaera (Sargeant) Sargeant †
• Acanthogonyaulax paliuros (Sargeant) Sargeant †
• Acanthogonyaulax spinifera (Murray & Whitting) H.W.Graham, 1942
• Acanthogonyaulax venusta (Klement) Sarjeant (uncertain)
• Acavomonas peruviana Tikhonenkov, Janouškovec, Mylnikov, Mikhailov, Simdyanov, Aleoshin & P.J.Keeling, 2014
• Achomosphaera alcicornu (Eisenack) R.J.Davey & G.L.Williams, 1966 †
• Achomosphaera antleriformis P.Schiøler †
• Achomosphaera argesensis E.Demetrescu †
• Achomosphaera gralliforme (Brosius) R.J.Davey & G.L.Williams, 1969 †
• Achomosphaera hirundo (Eisenack) R.J.Davey & G.L.Williams, 1969 †
• Achomosphaera hyperacantha (Deflandre & Cookson) R.J.Davey & G.L.Williams, 1969 † accepted as Gonyaulax spinifera (Claparède & Lachmann) Diesing, 1866
• Achomosphaera improcera M.A.Islam, 1983 †
• Achomosphaera linifera (Cookson & Eisenack) Stover & Evitt, 1978 †
• Achomosphaera neptuni (Eisenack) R.J.Davey & G.L.Williams, 1966 †
• Achomosphaera ramulifera (Deflandre) Evitt (uncertain)
• Achomosphaera ramulifera var. perforata R.J.Davey & G.L.Williams, 1966 †
• Achomosphaera recurvata K.P.Jain, S.C.D.Sah & R.Y.Singh †
• Achomosphaera regiensis Corradini (uncertain)
• Achomosphaera sagena R.J.Davey & G.L.Williams, 1966 †
• Achomosphaera septata (Cookson & Eisenack) Stover & Evitt (uncertain)
• Achomosphaera triangulata (Gerlach) R.J.Davey & G.L.Williams, 1969 †
• Achradina angusta Lohmann, 1920 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra Lohmann, 1903 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. aciculata Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. angustata (Lohmann) Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. nervosa Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. reticulata (Lohmann) Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. spatulata Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. sulcata (Lohmann) Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina pulchra f. truncata Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina reticulata Lohmann, 1920 accepted as Achradina pulchra f. reticulata (Lohmann) Nival, 1969 accepted as Monaster rete F.Schütt, 1895
• Achradina sulcata Lohmann, 1920 accepted as Monaster rete F.Schütt, 1895
• Actiniscus biseptenarius Ehrenberg (uncertain)
• Actiniscus canadensis Bursa ex Carty, 2014
• Actiniscus chaixi E.Paréjas (uncertain)
• Actiniscus colleti Paréjas, 1934 † accepted as Discoaster colletii (Paréjas) Bersier, 1939 †
• Actiniscus duodenarius simplex Ehrenberg (uncertain)
• Actiniscus elegans (Ehrenberg) Ehrenberg (uncertain)
• Actiniscus elongatus Dumitrică, 1968 †
• Actiniscus flosculus S.Locker & E.Martini, 1986 †
• Actiniscus heptagonus Ehrenberg (uncertain)
• Actiniscus laciniatus S.Locker & E.Martini, 1986 †
• Actiniscus lancearius Ehrenberg (uncertain)
• Actiniscus pennatus Grunow, 1882 accepted as Corethron pennatum (Grunow) Ostenfeld, 1909
• Actiniscus pentasterias (Ehrenberg) Ehrenberg, 1844
• Actiniscus pentasterias var. arcticus Bursa ex Moestrup & Calado, 2018
• Actiniscus quinarius Ehrenberg (uncertain)
• Actiniscus radicula Dumitrică (uncertain)
• Actiniscus rota Ehrenberg (uncertain)
• Actiniscus septenarius Ehrenberg (uncertain)
• Actiniscus sexfurcatus Ehrenberg (uncertain)
• Actiniscus squamosus S.Locker & E.Martini, 1986 †
• Actiniscus stella (Ehrenberg) Ehrenberg, 1844 † accepted as Discoaster aster Bramlette & W.R.Riedel, 1954 †
• Actiniscus talmadgei D.L.Parke (uncertain)
• Actiniscus tetras Ehrenberg (uncertain)
• Actiniscus varians (H.S.Lauder) Grunow, 1882 accepted as Bacteriastrum hyalinum Lauder, 1864
• Actinodinium apsteinii Chatton & Hovasse
• Actinodinium paradoxum (M.Rose & J.Cachon) Hollande & Enjumet, 1953 accepted as Cachonella paradoxa (M.Rose & J.Cachon) M.Rose & J.Cachon, 1952
• Actinotheca aphroditae Cookson & Eisenack, 1960 †
• Actinotheca ornata Cookson & Eisenack (uncertain)
• Actinotheca rara Corradini (uncertain)
• Adenoides eludens (Herdman) Balech, 1956
• Adenoides kofoidii (Herdman) J.D.Dodge, 1982 accepted as Pseudadenoides kofoidii (Herdman) F.Gómez, R. Onuma, Artigas & Horiguchi, 2015
• Adenoides sinensis H.Gu, X.Li & Z.Luo, 2018
• Adinimonas oviformis J.Schiller, 1928
• Adnatosphaeridium aemulum (Deflandre) G.L.Williams & C.Downie (uncertain)
• Adnatosphaeridium caulleryi (Deflandre) G.L.Williams & C.Downie (uncertain)
• Adnatosphaeridium chonetum (Cookson & Eisenack) Davey (uncertain)
• Adnatosphaeridium filamentosum (Cookson & Eisenack) G.L.Williams & C.Downie (uncertain)
• Adnatosphaeridium filiferum (Cookson & Eisenack) G.L.Williams & C.Downie (uncertain)
• Adnatosphaeridium multispinosum G.L.Williams & C.Downie, 1966 †
• Adnatosphaeridium patulum G.L.Williams & C.Downie, 1966 †
• Adnatosphaeridium regulatum Willumsen, 2012 †
• Adnatosphaeridium vetusculum R.J.Davey, 1974 † accepted as Nexosispinum vetusculum (R.J.Davey) R.J.Davey †
• Adnatosphaeridium vittatum G.L.Williams & C.Downie, 1966 †
• Adnatosphaeridium williamsii M.A.Islam, 1983 †
• Aduncodinium glandula (E.C.Herdman) N.S.Kang, H.J.Jeong & Moestrup, 2015 (uncertain)
• Agrosphaera pellucida Lo Bianco, 1903
• Ailadinium reticulatum Saburova & Chomérat, 2014
• Aiora fenestrata (Deflandre & Cookson) Cookson & Eisenack (uncertain)
• Aiora perforare R.J.Davey †
• Aireiana salictum Damassa, 1979 †
• Akashiwo sanguinea (K.Hirasaka) Gert Hansen & Moestrup, 2000
• Alasphaera caudata H.Keupp, 1979 †
• Alasphaera tuberculata (Pflaumannn & Krasheninnikov) Keupp † (uncertain)
• Alatosphaera hermosillae (Carbonell-Moore) Nézan, Carbonell-Moore, K.N.Mertens & Chomérat, 2023
• Albertia curvicornis Vozzhennikova, 1967 † (uncertain)
• Albertia recticornis Vozzhennikova, 1967 † (uncertain)
• Aldorfia dictyota (Cookson & Eisenack) R.J.Davey †