• [non-Uristidae] albinus (K.H. Barnard, 1932)
• [non-Uristidae] dawsoni Hurley, 1963
• [non-Uristidae] georgianus (Schellenberg, 1931)
• [non-Uristidae] natalensis K.H. Barnard, 1916
• Aackia karakoramensis Yosii, 1966
• Aahithis erraticus (Schallreuter, 1985) †
• Aahithis vanspronsenae Schallreuter, 1988 †
• Aaleniella (Aaleniella) compressa Plumhoff, 1963 † represented as Aaleniella compressa Plumhoff, 1963 †
• Aaleniella (Danocythere) gracilis Christensen & Kilenyi, 1970 †
• Aaleniella (Danocythere) inornata (Kilenyi, 1969) †
• Aaleniella compressa Plumhoff, 1963 †
• Aaleniella cuneata Wakefield, 1994 †
• Aaleniella franzi Tesakova, E. M. †
• Aaleniella reticulata Knitter, 1983 †
• Aaleniella volganica Tesakova, E. M. †
• Aaptolasma fosteri (Newman & Ross, 1971) accepted as Mesolasma fosteri (Newman & Ross, 1981)
• Aatolana rapax Bruce, 1993
• Aatolana schioedtei (Miers, 1884)
• Aatolana springthorpei Keable, 1998
• Abacion creolum (Chamberlin, 1942) accepted as Abacion tesselatum Rafinesque, 1820
• Abacion highlandense (Hoffman, 1950) accepted as Abacion magnum (Loomis, 1943)
• Abacion lactarium (Say, 1821)
• Abacion magnum (Loomis, 1943)
• Abacion spinosa (Sager, 1856) accepted as Abacion tesselatum Rafinesque, 1820
• Abacion tesselatum Rafinesque, 1820
• Abacion tesselatum creolum (Chamberlin, 1942)
• Abacion texensis (Loomis, 1937)
• Abacion wilhelminae Shelley, McAllister & Hollis, 2003
• Abasia inflata Cressey & Cressey, 1979
• Abasia pillaii Cressey & Cressey, 1979
• Abasia platyrostris Pillai, 1963
• Abasia pseudorostris Wilson C.B., 1908
• Abasia pusilla Cressey & Cressey, 1979
• Abasia tripartita (Shiino, 1955)
• Abatetia robusta (Parent, 1933)
• Abathescalpellum fissum (Hoek, 1907)
• Abathescalpellum koreanum (Hiro, 1933)
• Abatodesmus chilensis Silvestri, 1903
• Abatodesmus simplicior Golovatch, 2014
• Abatodesmus velosoi Demange & Silva, 1971
• Abdia latipalpus (Walker & Scott, 1903)
• Abdiacyclops cirratus Karanovic, 2005
• Abditacythere subterranea Hartmann, 1964
• Abditoloculina binodata Kesling & Peterson, 1958 †
• Abditoloculina cavimarginata (Ulrich, 1900) †
• Abditoloculina filaloculina Tillman & Murphy, 1978 †
• Abebaioscia troglodytes Vandel, 1973
• Abergasilus amplexus Hewitt, 1978
• Aberomysis muranoi Bacescu & Iliffe, 1986
• Aberratylus aberrantis (J.L. Barnard, 1962)
• Aberroconcha anodontoides (Rome & Goreux, 1960) †
• Aberroconcha circularis (Rome & Goreux, 1960) †
• Aberroconcha complanata (Rome & Goreux, 1960) †
• Aberroconcha cordiformis (Rome & Goreux, 1960) †
• Aberroconcha devonica Adamczak, 1961 †
• Aberroconcha diatropa (Jones, 1962) †
• Aberroconcha elliptica (Rome & Goreux, 1960) †
• Aberroconcha geniculata (Rome & Goreux, 1960) †
• Aberroconcha inflata (Rome & Goreux, 1960) †
• Aberroconcha ivanica (Krandijevsky, 1963) †
• Aberroconcha lisowzyensis (Krandije, 1958) †
• Aberroconcha magna (Harris, 1931) †
• Aberroconcha obliqua (Rome & Goreux, 1960) †
• Aberroconcha platyogma (Jones, 1962) †
• Aberroconcha plicata Adamczak, 1961 †
• Aberroconcha simpsoni (Harris, 1931) †
• Aberroconcha triangularis (Rome & Goreux, 1960) †
• Abgrallaspis cyanophylli (Signoret, 1869)
• Abiliodesmus cataractae (Hoffman, 1976)
• Abiliodesmus defensor (Hoffman, 1976)
• Abiliodesmus mapinguari Bouzan, Iniesta & Brescovit, 2021
• Abiliodesmus planaltensis (Schubart, 1960)
• Ablabesmyia mala (Hutton, 1902)
• Abludogammarus flavus (Dybowsky, 1874)
• Abludomelita aculeata (Chevreux, 1911)
• Abludomelita amoena (Hansen, 1888)
• Abludomelita breviarticulata (Ren, 2012)
• Abludomelita denticulata (Nagata, 1965)
• Abludomelita gladiosa (Spence Bate & Westwood, 1862)
• Abludomelita huanghaiensis (Ren, 2012)
• Abludomelita japonica (Nagata, 1965)
• Abludomelita klitinii Labay, 2016
• Abludomelita machaera (K.H. Barnard, 1955) accepted as Saldanha machaera (K.H. Barnard, 1955)
• Abludomelita mucronata (Griffiths, 1975)
• Abludomelita obtusata (Montagu, 1813)
• Abludomelita okhotensis Labay, 2016
• Abludomelita richardi (Chevreux, 1900)
• Abludomelita rotundactyla (Ren, 2012) accepted as Abludomelita breviarticulata (Ren, 2012)
• Abludomelita somovae (Bulyčeva, 1952)
• Abludomelita unamoena (Hirayama, 1987)
• Abnitocrella eberhardi Karanovic, 2006
• Abnitocrella halsei Karanovic, 2006
• Aboilia blessi Becker & Adamczak, 1993 †
• Abormon capillosum Mitra, Pati & Ng, 2021
• Abormon praecalvum Mitra, Pati & Ng, 2021
• Aborolobatea insidiosa Hughes & Lowry, 2009
• Aborolobatea paracheliformis Ledoyer, 1984
• Abortelphusa namdaphaensis Mitra, 2020
• Abortivelum truncatum Berdan & Copeland, 1973 †
• Abrocythereis feishania Hu & Tao, 2008