• Abditodentrix pseudothalmanni (Boltovskoy & Guissani de Kahn, 1981): Miocene
• Abertella gualichensis Martínez, Reichler & Mooi, 2005 †: Miocene
• Abertella kewi Durham, 1957 †: Miocene
• Abra cytheraeformis Cossmann & Peyrot, 1909 †: Aquitanian
• Abra fragosa (Marwick, 1931) †: Miocene
• Abra marshalli (H. J. Finlay, 1927) †: Miocene
• Acanthocardia allae Studencka & Popov, 1996 †: Miocene
• Acanthocardia andreae (Dujardin, 1837) †: Miocene
• Acanthocardia leognanensis (Mayer, 1866) †: Burdigalian
• Acanthocardia otarii (Kharatishvili, 1952) †: Miocene
• Acanthocardia saucatsensis (Mayer, 1866) †: Burdigalian
• Acanthocardia subserrigera (A. d'Orbigny, 1852) †: Aquitanian
• Acanthocardia turonica (M. Hörnes, 1861) †: Miocene
• Acanthochitona globosa Dell'Angelo, Landau, Van Dingenen & Ceulemans, 2018 †: Tortonian
• Acasta schafferi de Alessandri, 1910 †: Miocene
• Acharax muroensis (Natori, 1964) †: Aquitanian
• Acicula crassistoma Stworzewicz & Sołtys, 1996 †: Langhian
• Acicula crassistoma Stworzewicz & Sołtys, 1996 †: Burdigalian
• Acicula giuntellii Harzhauser, Neubauer & Esu, 2015 †: Messinian
• Acicula kadolskyi Manganelli, Cianfanelli, Barbato & Benocci, 2014 †: Messinian
• Acicula limbata Reuss, 1861 †: Burdigalian
• Acila antefultoni Slodkevich, 1967 †: Miocene
• Acirsa awamoaensis (P. Marshall & Murdoch, 1921) †: Miocene
• Acirsa fusiformis Harzhauser & Landau, 2025 †: Langhian
• Acirsa lanceolata (Brocchi, 1814) †: Tortonian
• Acirsa miopedemontana Sacco, 1891 †: Burdigalian
• Acirsa sceauxsensis Landau, Ceulemans & Van Dingenen, 2018 †: Tortonian
• Acirsa subnodulosa (P. A. Maxwell, 1988) †: Miocene
• Aclis ascaris (W. Turton, 1819): Tortonian
• Acremodontina maxwelli B. A. Marshall, 1995 †: Miocene
• Acroloxus anatolicus Schütt, 1984 †: Langhian
• Acroloxus ucrainicus Gozhik & Prysjazhnjuk, 1978 †: Tortonian
• Acrosterigma delectabile (P. A. Maxwell, 1978) †: Miocene
• Acrosterigma fraternum (Mayer, 1864) †: Burdigalian
• Acrosterigma fraternum (Mayer, 1864) †: Aquitanian
• Actapericulum bicarinatum Holmes, 1995 †: Langhian
• Actapericulum bicarinatum Holmes, 1995 †: Burdigalian
• Acteon chilensis R. A. Philippi, 1887 †: Burdigalian
• Acteon oneroaensis A. W. B. Powell & Bartrum, 1929 †: Miocene
• Acteon otamateaensis Laws, 1941 †: Miocene
• Actinobalanus dolosus (Darwin, 1854) †: Miocene
• Actinopora armorica (Michelin, 1847) †: Miocene
• Actinopora plicata Canu, 1916 †: Burdigalian
• Adenifera striata (MacGillivray, 1895) †: Miocene
• Adeonellopsis maghrebensis El Hajjaji, 1992 †: Messinian
• Adeonellopsis sandbergi Di Martino, Taylor & Portell, 2017 †: Burdigalian
• Admetula serrata (Bronn, 1831) †: Tortonian
• Aechmella poluzzii Moissette, 1988 †: Miocene
• Aetea truncata (Landsborough, 1852): Miocene
• Afripupa kenyensis Pickford, 2019 †: Burdigalian