• Aaleniella variata M. A. Conti & J. C. Fischer, 1981 †: Aalenian
• Absurdaster meriani (Ooster, 1865) †: Cretaceous, Lower
• Absurdaster puezensis Kroh, Lukeneder & Gallemí, 2014 †: Barremian
• Absurdaster puezensis Kroh, Lukeneder & Gallemí, 2014 †: Hauterivian
• Abyssomelania campbellae Kaim, R. G. Jenkins, Tanabe & Kiel, 2014 †: Albian
• Acanomyphoria tuberosa F.-X. Guo, 1985 †: Triassic, Upper
• Acanthopora haimei Etallon, 1859 †: Jurassic
• Acanthopora icaunensis d'Orbigny, 1850 †: Valanginian
• Acanthopora lamourouxi Haime, 1854 †: Jurassic
• Acanthopora pulchella de Loriol, 1868 †: Hauterivian
• Acanthopora pulchella de Loriol, 1868 †: Valanginian
• Acesta brycei Marwick, 1953 †: Oxfordian
• Acesta brycei Marwick, 1953 †: Bathonian
• Acesta brycei Marwick, 1953 †: Aalenian
• Acesta marlburiensis (H. Woods, 1917) †: Santonian
• Acesta marlburiensis (H. Woods, 1917) †: Turonian
• Acesta marlburiensis (H. Woods, 1917) †: Cenomanian
• Acharax stantoni (H. E. Vokes, 1955) †: Barremian
• Acirsa culmosa Sohl, 1964 †: Campanian
• Acirsa pacifica (Wilckens, 1922) †: Maastrichtian
• Acirsa pacifica (Wilckens, 1922) †: Campanian
• Acoscinopleura albaruthenica Koromyslova, Martha & Pakhnevich, 2018 †: Campanian
• Acoscinopleura artemis (d'Orbigny, 1851) †: Maastrichtian
• Acoscinopleura crassa Koromyslova, Martha & Pakhnevich, 2018 †: Maastrichtian
• Acoscinopleura dualis Koromyslova, Martha & Pakhnevich, 2018 †: Maastrichtian
• Acoscinopleura fallax Voigt, 1956 †: Maastrichtian
• Acriaster sergipensis Smith in Smith & Benggtson, 1991 †: Albian
• Acrocidaris arginensis Weber, 1934 †: Hauterivian
• Acrocidaris borissiaki Weber, 1934 †: Jurassic, Upper
• Acrocidaris nicolleaui Vadet & Nicolleau, 2000 †: Callovian
• Acropeltis atlantica Rey, Taj-Eddine & Witam, 1989 †: Valanginian
• Acrosalenia bowersi Kier, 1972a †: Callovian
• Acrosalenia marratensis Kier, 1972a †: Toarcian
• Acrosalenia mideltensis Vadet, Nicolleau & Reboul, 2010 †: Bajocian
• Acrosalenia smelliei Currie, 1925 †: Bathonian
• Acrosalenia somaliensis Currie, 1925 †: Jurassic, Lower
• Acrosalenia zararensis Lambert, 1937 †: Pliensbachian
• Acteon marullensis A. d'Orbigny, 1850 †: Hauterivian
• Acteonella agricolai Vidal, 1921 †: Maastrichtian
• Acteonella crassa (Dujardin, 1835) †: Coniacian
• Acteonella fusiformis Coquand, 1865 †: Aptian
• Acteonella involuta Coquand, 1860 †: Santonian
• Acteonella sublaevis Briart & Cornet, 1868 †: Albian
• Acteonina novozealandica Bandel, Gründel & P. A. Maxwell, 2000 †: Callovian
• Acteonina novozealandica Bandel, Gründel & P. A. Maxwell, 2000 †: Bajocian
• Acteonina novozealandica Bandel, Gründel & P. A. Maxwell, 2000 †: Aalenian
• Acteonina novozealandica Bandel, Gründel & P. A. Maxwell, 2000 †: Toarcian
• Acteonina novozealandica Bandel, Gründel & P. A. Maxwell, 2000 †: Pliensbachian
• Actinopora auei Voigt, 1996 †: Cretaceous
• Actinopora bowerbanki (Haime, 1854) †: Aalenian
• Actinopora brongniarti (Milne-Edwards, 1837) †: Cretaceous