• Acanthocystis aculeata Hert. Less.
• Acanthoica cidaris var. undulata J.Schlauder (uncertain)
• Acanthoica ordinata Kamptner, 1941 accepted as Alisphaera ordinata (Kamptner) Heimdal, 1973
• Actimonas mirabilis
• Agalmatoaster broennimannii Ben Prins (uncertain)
• Ahmuellerella angusta (Stradner) Reinhardt, 1965 † accepted as Rhagodiscus angustus (Stradner) P.Reinhardt, 1971 †
• Ahmuellerella retiformis Reinhardt (uncertain)
• Algirosphaera quadricornu (Schiller) R.E.Norris, 1984
• Alisphaera memoria Doan-Nhu, 2021
• Amaurolithus ninae Perch-Nielsen, 1977 †
• Anacanthoica lithostratos (J.Schiller) R.E.Norris, 1984 accepted as Acanthoica lithostratos J.Schiller, 1926
• Anoplosolenia brasiliensis (Lohmann) Deflandre, 1952 accepted as Calciosolenia brasiliensis (Lohmann) J.R.Young, 2003
• Anthosphaera oryza (Lecal-Schlauder) Gaarder, 1971 accepted as Algirosphaera oryza Lecal-Schlauder, 1945
• Acanthocystis paliformis
• Acanthoica coronata Lohmann, 1903
• Acanthoica ornata Conrad, 1928
• Actinosphaera deflandrei D.Noël, 1965 † accepted as Watznaueria barnesiae (M.Black) Perch-Nielsen, 1968 †
• Agalmatoaster cruciformis Ben Prins (uncertain)
• Ahmuellerella biramiculata (Stover) N.Hoffmann (uncertain)
• Ahmuellerella splendens (Deflandre) Reinhardt (uncertain)
• Algirosphaera robusta (Lohmann) R.E.Norris, 1984
• Alisphaera ordinata (Kamptner) Heimdal, 1973
• Amaurolithus peregrinus Chongyou Wang, 1985 †
• Anacanthoica ornata (Conrad) Bourrelly, 1968 accepted as Acanthoica ornata Conrad, 1928
• Ansulasphaera helvetica Grün & Zweili, 1980 †
• Anthosphaera periperforata Kleijne, 1991 accepted as Syracosphaera periperforata (Kleijne) Archontikis, Young & Cros, 2020
• Acanthocystis turfacea
• Acanthoica janchenii Schiller, 1925
• Acanthoica quattrospina var. mediterranea Lecal-Schlauder (uncertain)
• Actinozygus splendens (Deflandre) Gartner (uncertain)
• Agalmatoaster mirus Ben Prins (uncertain)
• Ahmuellerella granulata P.Reinhardt † accepted as Tetrapodorhabdus decorus (Deflandre) Wind & S.W.Wise, 1977 †
• Algirosphaera campanula Lecal-Schlauder (uncertain)
• Alisphaera bidentata Malinverno, 2022
• Alisphaera uncinata Kleijne, Jordan, Heimdal, Samtleben, A.H.L.Chamberlain & Cros, 2002
• Amphizygus microminutus J.G.Hattner & S.W.Wise †
• Anfractus variabilis Medd, 1979 †
• Anthosphaera coronata Gaarder (uncertain)
• Acanthoica cidaris Lecal-Schlauder, 1945 accepted as Anacanthoica cidaris (Lecal-Schlauder) Kleijne, 1992 accepted as Cyrtosphaera cidaris (Lecal-Schlauder) J.R.Young & Bown, 2014
• Acanthoica monospina Schiller, 1914
• Acanthosolenia mediterranea F.C.Bernard, 1939
• Agalmatoaster binodosus Ben Prins (uncertain)
• Agalmatoaster septemradiatus Klumpp, 1953 † accepted as Discoaster septemradiatus (Klumpp) Martini
• Ahmuellerella regularis (Górka) P.Reinhardt & Górka †
• Algirosphaera oryza Lecal-Schlauder, 1945
• Alisphaera gaudii Kleijne, Jordan, Heimdal, Samtleben, Chamberlain & Cros, 2002
• Alvearium dorsetense Black † (uncertain)
• Anacanthoica cidaris (Lecal-Schlauder) Kleijne, 1992 accepted as Cyrtosphaera cidaris (Lecal-Schlauder) J.R.Young & Bown, 2014
• Annulithus arkellii Rood, Hay & Barnard (uncertain)
• Anthosphaera origami Cros & McGrane, 2014 accepted as Syracosphaera origami (Cros & McGrane) Archontikis, Young & Cros, 2020
• Acanthocystis perpusilla
• Acanthoica cucullata f. diademata M.Gardet, 1955 accepted as Helicosphaera ampliaperta Bramlette & Wilcoxon † accepted as Helicopontosphaera ampliaperta (Bramlette & Wilcoxon) Hay †
• Acanthoica quattrospina var. brevispina (Schiller) Schiller (uncertain)
• Actinozygus regularis (Górka) Gartner (uncertain)
• Agalmatoaster gemmifer Ben Prins (uncertain)
• Ahmuellerella granulata (Stover) Shumenko, 1976 † accepted as Rhagodiscus asper (Stradner) Reinhardt, 1967 †
• Algirosphaera bicornis (Lecal-Schlauder) Norris, 1984
• Aliculosphaera subantarctica (A.R.Edwards & Perch-Nielsen) M.P.Aubry & Bord, 2009 †
• Alisphaera quadrilatera Kleijne, Jordan, Heimdal, Samtleben, Chamberlain & Cros, 2002
• Amphizygus brooksii subsp. nanus Bukry (uncertain)
• Anfractus harrisonii Medd, 1979 †
• Anthosphaera bicornis Lecal-Schlauder, 1945 accepted as Algirosphaera bicornis (Lecal-Schlauder) Norris, 1984
• Anthosphaera robusta (Lohmann) Kamptner, 1941 accepted as Algirosphaera robusta (Lohmann) R.E.Norris, 1984
• Acanthoica aculeata Kamptner, 1941 accepted as Cyrtosphaera aculeata (Kamptner) A.Kleijne, 1992
• Acanthoica maxima Heimdal, 1981
• Acanthoica schilleri Conrad, 1928
• Aethiopites circularis Caratini cent.nov. † (uncertain)
• Agalmatoaster munitus Ben Prins (uncertain)
• Ahmuellerella quadriarcula (D.Noël) D,Noël † accepted as Staurolithites quadriarculus (D.Noël) Wilcoxon, 1972 †
• Algirosphaera cucullata (Lecal-Schlauder) J.R.Young, Probert & Kleijne, 2003
• Alisphaera extenta Kleijne, R.W.Jordan, Heimdal, Samtleben, A.H.L.Chamberlain & Cros, 2002
• Allemannites romani (Górka) Górka
• Anacanthoica caballicarus Lecal-Schlauder, 1967 accepted as Acanthoica quattrospina Lohmann, 1903
• Angulofenestrellithus snyderi Bukry, 1969 † accepted as Angulofenestrellithus numerosus (Górka) Shumenko, 1976 †
• Anthosphaera lafourcadei (Lecal-Schlauder) Kleijne, 1991 (uncertain)
• Acanthocystis pelagica
• Acanthoica cucullata Lecal-Schlauder, 1951 accepted as Algirosphaera cucullata (Lecal-Schlauder) J.R.Young, Probert & Kleijne, 2003
• Acanthoica quattrospina Lohmann, 1903
• Actinozygus fragilis Rood & Barnard, 1972 † (uncertain)
• Agalmatoaster distinctus Ben Prins (uncertain)
• Ahmuellerella dietzmannii P.Reinhardt, 1965 † accepted as Axopodorhabdus dietzmannii (P.Reinhardt) Wind & S.W.Wise, 1977 †
• Algirosphaera aurea (C.Bernard & Lecal-Schlauder) R.E.Norris, 1984
• Algirosphaera spinulosa Lecal-Schlauder (uncertain)
• Alisphaera pinnigera Kleijne, Jordan, Heimdal, Samtleben, A.H.L.Chamberlain & Cros, 2002
• Amithalithina sigmundii J.J.Pospichal & S.W.Wise †
• Anacanthoica salomonica Varol, 1989 †
• Anthosphaera aurea C.Bernard & Lecal-Schlauder, 1960 accepted as Algirosphaera aurea (C.Bernard & Lecal-Schlauder) R.E.Norris, 1984
• Anthosphaera quadricornu (J.Schiller) Halldal & Markali, 1955 accepted as Algirosphaera quadricornu (Schiller) R.E.Norris, 1984
• Acanthoica acanthifera Lohmann ex Lohmann, 1913
• Acanthoica lithostratos J.Schiller, 1926
• Acanthoica rubus Kamptner (uncertain)
• Acuturris scota (Risatti) Wind & S.W.Wise, 1977 †
• Agalmatoaster monstratus Ben Prins (uncertain)
• Ahmuellerella mirabilis (Perch-Nielsen) Shumenko, 1976 † accepted as Ahmuellerella regularis (Górka) P.Reinhardt & Górka †
• Algirosphaera capulata Heimdal, 1981
• Alisphaera capulata Heimdal, 1981
• Alisphaera unicornis Okada & McIntyre, 1977
• Anacanthoica acanthos (J.Schiller) Deflandre, 1952 accepted as
• Angulofenestrellithus numerosus (Górka) Shumenko, 1976 †
• Anthosphaera fragaria Kamptner, 1937 accepted as Syracosphaera molischii J.Schiller, 1925