• Abditodentrix pseudothalmanni (Boltovskoy & Guissani de Kahn, 1981): Holocene
• Abditodentrix pseudothalmanni (Boltovskoy & Guissani de Kahn, 1981): Pleistocene
• Acanthocardia deshayesii (Payraudeau, 1826): Calabrian
• Acanthochitona interglacialis Dell'Angelo, Landau, Sosso & Taviani, 2020 †: Pleistocene, Upper
• Acanthochitona mastalleri Strack, 1989: Pleistocene, Upper
• Acanthochitona penicillata (Deshayes, 1863): Pleistocene, Upper
• Acanthochitona zelandica (Quoy & Gaimard, 1835): Holocene
• Acanthochitona zelandica (Quoy & Gaimard, 1835): Pleistocene
• Acanthocidaris curvatispinis (Bell, 1892): Holocene
• Acanthocidaris hastigera A. Agassiz & H.L. Clark, 1907: Holocene
• Acanthocidaris maculicollis (de Meijere, 1904): Holocene
• Acanthodesia variegata Di Martino & Taylor, 2018 †: Holocene
• Acanthoporella triangularis (Canu & Bassler, 1923) †: Pleistocene
• Acanthotrophon striatoides E. H. Vokes, 1980: Pleistocene
• Acar sandersonae A. W. B. Powell, 1933: Holocene
• Acar sandersonae A. W. B. Powell, 1933: Pleistocene
• Acar sociella (Brookes, 1926): Holocene
• Acar sociella (Brookes, 1926): Pleistocene
• Acar whangaensis (Marwick, 1928) †: Pleistocene
• Acesta imitata (Suter, 1917) †: Pleistocene
• Acirsa cookiana (Dell, 1956): Holocene
• Acirsa cookiana (Dell, 1956): Pleistocene
• Aclis planostoma (F. W. Hutton, 1885) †: Pleistocene
• Acremodontina varicosa B. A. Marshall, 1995: Holocene
• Acremodontina varicosa B. A. Marshall, 1995: Pleistocene
• Acteon traskii Stearns, 1897: Quaternary
• Actinella fecundaerrata Groh & Cameron, 2019 †: Quaternary
• Actinobalanus inclusus (Darwin, 1854): Pleistocene
• Acuticosta prolonga Zykin, 1980 †: Gelasian
• Adacna praeplicata V. P. Kolesnikov, 1950 †: Calabrian
• Adacna praepraeplicata G. I. Popov, 1961 †: Calabrian
• Adacna yaninae Büyükmeriç & Wesselingh, 2018 †: Pleistocene, Upper
• Adeona nipponica Kataoka, 1961 †: Pleistocene
• Adeonella adae (Neviani, 1891) †: Pleistocene
• Adeonella watersi Hennig, 1911 †: Pleistocene
• Adeonellopsis pentapora Canu & Bassler, 1929: Pleistocene
• Aechmella globosa Kataoka, 1961 †: Pleistocene
• Aegopinella bourdieri Rousseau & Puisségur, 1989 †: Pleistocene, Middle
• Aegopis klemmi Schlickum & Ložek, 1965 †: Pleistocene, Middle
• Aegopis klemmi Schlickum & Ložek, 1965 †: Calabrian
• Aegopis klemmi Schlickum & Ložek, 1965 †: Gelasian
• Agaronia adamii Terzer, 1992: Holocene
• Agaronia gibbosa (Born, 1778): Holocene
• Agaronia gibbosa (Born, 1778): Pleistocene
• Agatha georgiana (F. W. Hutton, 1885): Holocene
• Agatha georgiana (F. W. Hutton, 1885): Pleistocene
• Agnewia kempae A. W. B. Powell, 1934 †: Pleistocene
• Agnewia tritoniformis (Blainville, 1832): Holocene
• Agnewia tritoniformis (Blainville, 1832): Pleistocene
• Agrenocythere hazeli (Bold, 1946): Holocene
• Aimulosia aculeata Canu & Bassler, 1923 †: Pleistocene
• Aimulosia manzonii (Neviani, 1896) †: Pleistocene
• Akatopora tincta (Hastings, 1930): Pleistocene
• Akera soluta (Gmelin, 1791): Holocene
• Akera soluta (Gmelin, 1791): Pleistocene
• Alabaminella weddellensis (Earland, 1936): Holocene
• Alabaminella weddellensis (Earland, 1936): Pleistocene
• Alabina monicensis Bartsch, 1911 †: Pleistocene
• Alcithoe arabica (Gmelin, 1791): Holocene
• Alcithoe arabica (Gmelin, 1791): Pleistocene
• Alcithoe bartrumi (L. C. King, 1933) †: Pleistocene
• Alcithoe brevis Marwick, 1926 †: Pleistocene
• Alcithoe exigua Marwick, 1926 †: Pleistocene
• Alcithoe fusus (Quoy & Gaimard, 1833): Holocene
• Alcithoe fusus (Quoy & Gaimard, 1833): Pleistocene
• Alcithoe resolutionensis C. A. Fleming, 1954 †: Pleistocene
• Alcithoe wilsonae (A. W. B. Powell, 1933): Holocene
• Alcithoe wilsonae (A. W. B. Powell, 1933): Pleistocene
• Alizadella aktschagylica Kabakova, 1966 †: Gelasian
• Alvania acida Garilli, Reitano & Scuderi, 2023: Pleistocene, Upper
• Alvania agathae Reitano, Cresti & Di Franco, 2020 †: Pleistocene
• Alvania ameliae Chirli & Forli, 2021 †: Pleistocene
• Alvania baldoi Garilli & Parrinello, 2010 †: Pleistocene
• Alvania bartschi Olsson, 1942 †: Pleistocene
• Alvania calliope Chirli & U. Linse, 2011 †: Calabrian
• Alvania erato Chirli & U. Linse, 2011 †: Calabrian
• Alvania francescoi Garilli, 2008 †: Pleistocene
• Alvania ismar Amati, Taviani & Oliverio, 2024 †: Pleistocene
• Alvania kermadecensis (W. R. B. Oliver, 1915): Holocene
• Alvania kermadecensis (W. R. B. Oliver, 1915): Pleistocene
• Alvania laurae Brunetti & Vecchi, 2012 †: Pleistocene
• Alvania leopardiana Brunetti & Vecchi, 2012 †: Pleistocene
• Alvania nitida Brunetti & Vecchi, 2012 †: Pleistocene
• Alvania pseudohispidula Brunetti & Vecchi, 2012 †: Pleistocene
• Alvania ziliolii Brunetti & Vecchi, 2012 †: Pleistocene
• Ambocythere whatleyi Yasuhara, Hunt, Okahashi & Brandão, 2015: Quaternary
• Ammonia aoteana (Finlay, 1940): Holocene
• Ammonia aoteana (Finlay, 1940): Pleistocene
• Amnicola omphalotropis Pilsbry, 1892 †: Calabrian
• Amphiblestrum frigidum Rosso, 2002: Pleistocene
• Amphiblestrum ryukuensis Kataoka, 1961 †: Pleistocene
• Amphibola crenata (Gmelin, 1791): Holocene
• Amphibola crenata (Gmelin, 1791): Pleistocene
• Amphicoryna bradii (Silvestri, 1902): Pleistocene, Middle
• Amphicoryna bradii (Silvestri, 1902): Calabrian
• Amphicoryna bradii (Silvestri, 1902): Gelasian
• Amphicoryna georgechapronierei Yassini & Jones, 1995: Holocene
• Amphicoryna georgechapronierei Yassini & Jones, 1995: Pleistocene
• Amphicoryna leurodeira Loeblich & Tappan, 1994: Calabrian
• Amphicoryna leurodeira Loeblich & Tappan, 1994: Gelasian