Abramovispirifer Baranov & Alkhovik, 2005 † (basis of record)
Abyssorhynchia Zezina, 1980 (basis of record)
Abyssorhynchia Zezina, 1980 (name verified source)
Acanthaphritis Günther, 1880 (verified source for family)
Acanthocorpa Oshmarin, 1963 accepted as Ignavia Teixeira de Freitas, 1948 (source of synonymy)
Acanthocorpa Oshmarin, 1963 accepted as Ignavia Teixeira de Freitas, 1948 (basis of record)
Acanthohamingia Ikeda, 1910 (name verified source)
Acanthohamingia Ikeda, 1910 (basis of record)
Acanthonotozomella Schellenberg, 1926 (verified source for family)
Acanthonotozomoides Schellenberg, 1931 (verified source for family)
Acanthopsaron Fricke, 2024 (verified source for family)
Acanthotheca Vendrasco, Kouchinsky, Porter & Fernandez, 2011 † (verified source for family)
Acropomatidae Gill, 1893 (taxonomy source)
Acropomatiformes (basis of record)
Actinacanthus Stebbing, 1888 (verified source for family)
Actinoposthiidae Hooge, 2001 (basis of record)
Acutocoxae Rauschert, 2017 (additional source)
Adeorbella Briart & Cornet, 1887 † (current name source)
Adeorbella Briart & Cornet, 1887 † (verified source for family)
Adipicola Dautzenberg, 1927 (verified source for family)
Aestuariumcypraea Daughenbaugh & Bridges, 2022 † accepted as Siphocypraea Heilprin, 1886 † (basis of record)
Aestuariumcypraea Daughenbaugh & Bridges, 2022 † accepted as Siphocypraea Heilprin, 1886 † (source of synonymy)
Agilestia Friend, 1982 (verified source for family)
Agnesia Michaelsen, 1898 accepted as Agnezia C. Monniot & F. Monniot, 1991 (source of synonymy)
Ainigma Helfer, 1938 accepted as Ascorhynchus Sars, 1878 (verified source for family)
Akessoniella Tsetlin & Larionov, 1988 accepted as Nerillidium Remane, 1925 (basis of record)
Akessoniella Tsetlin & Larionov, 1988 accepted as Nerillidium Remane, 1925 (source of synonymy)
Aktschagylia Starobogatov, 1970 (verified source for family)
Aktschagylia Starobogatov, 1970 (current name source)
Alatacythere Murray & Hussey, 1942 † accepted as Pterygocythereis Blake in Procter, 1933 (current name source)
Albacythere Kozur & Nicklas, 1970 † (basis of record)
Albidiator Lowry & Myers, 2019 (verified source for family)
Albitrigonia Prado-Velazco, 1991 accepted as Perugonia Kobayashi & Tamura, 1968 † (basis of record)
Alexlutheria Karling, 1956 (verified source for family)
Alienella Starobogatov & Zatravkin, 1985 accepted as Sibirovalvata Starobogatov & Streletzkaja, 1967 (source of synonymy)
Alienella Starobogatov & Zatravkin, 1985 accepted as Sibirovalvata Starobogatov & Streletzkaja, 1967 (basis of record)
Alluroteuthidae accepted as Neoteuthidae Naef, 1921 (source of synonymy)
Alpavlia Lazarev, 2011 † (verified source for family)
Altadema Kues, 2002 † (verified source for family)
Altaiproductus Lazarev, 2011 † (verified source for family)
Amatiguakius Coleman, 1991 (verified source for family)
Amekicarcinus Schweitzer, Odumodu & Feldmann, 2016 † (verified source for family)
Amniciana Servain, 1888 accepted as Pisidium C. Pfeiffer, 1821 (source of synonymy)
Amnigenia Hall, 1885 † (current name source)
Amnigenia Hall, 1885 † (verified source for family)
Amnigeniidae Khalfin, 1948 † (current name source)
Amnigeniidae Khalfin, 1948 † (taxonomy source)
Ampezzania Allasinaz in Allasinaz & Zardini, 1977 † (verified source for family)
Ampezzania Allasinaz in Allasinaz & Zardini, 1977 † (current name source)
Ampezzania Allasinaz in Allasinaz & Zardini, 1977 † (basis of record)
Amphiphora Alloiteau & Bernier, 1969 † accepted as Cyathophora Michelin, 1843 † (source of synonymy)
Amphisopidae Nicholls, 1943 (habitat flag source)
Amplidrupa Vermeij, 2023 (basis of record)
Amplidrupa Vermeij, 2023 (current name source)
Amplidrupa Vermeij, 2023 (verified source for family)
Amplocypris Zalanyi, 1944 † (current name source)
Amurohenslowiana Korniushin, 1996 accepted as Henslowiana Servain, 1888 (basis of record)
Amurohenslowiana Korniushin, 1996 accepted as Henslowiana Servain, 1888 (source of synonymy)
Anatolanthias Anderson, Parin & Randall, 1990 (verified source for family)
Anaucella Pchelintseva, 1955 † accepted as Buchia Rouillier, 1845 † (basis of record)
Anaucella Pchelintseva, 1955 † accepted as Buchia Rouillier, 1845 † (source of synonymy)
Ancistrocheiridae Pfeffer, 1912 (taxonomy source)
Angulocarinella Korchagin, 2001 † accepted as Whiteinella Pessagno, 1967 † (source of synonymy)
Angulomphalus Gründel, 2011 † (basis of record)
Angystoma Schumacher, 1817 accepted as Ringicella Gray, 1847 (source of synonymy)
Angystoma Schumacher, 1817 accepted as Ringicella Gray, 1847 (verified source for family)
Anisopsis Zilch, 1959 † accepted as Liangulorbis Wenz, 1947 † (source of synonymy)
Anisopsis Zilch, 1959 † accepted as Liangulorbis Wenz, 1947 † (basis of record)
Annuliconcha Newell, 1937 † (verified source for family)
Anostoma Fischer, 1807 (verified source for family)
Anostomopsidae Nordsieck, 1986 † (basis of record)
Anostomopsis Sandberger, 1871 (verified source for family)
Anthias Bloch, 1792 (verified source for family)
Anticythereis Bold, 1946 † (basis of record)
Antiquamitra Huang & Lin, 2026 † (basis of record)
Antiquamitridae Huang & Lin, 2026 † (taxonomy source)
Antiquamitridae Huang & Lin, 2026 † (basis of record)
Apotrachelotractus Long, Song & Warren, 2009 (basis of record)
Aralina Tsatsir, 1970 (basis of record)
Aralina Tsatsir, 1970 (verified source for family)
Archaeoplanorbis Yu in Guo, Yu & Pan, 1982 † (current name source)
Archaeoplanorbis Yu in Guo, Yu & Pan, 1982 † (verified source for family)
Archaeoplanorbis Yu in Guo, Yu & Pan, 1982 † (basis of record)
Archaeosmilia Melnikova, 1975 † (basis of record)
Archaeosmiliopsis Melnikova, 1975 † (basis of record)
Archanodon Howse, 1878 † (current name source)
Archanodon Howse, 1878 † (verified source for family)
Archinacellopsis Horný, 1995 † (current name source)
Architeuthidae Pfeffer, 1900 (taxonomy source)
Arcitalitrus Hurley, 1975 (verified source for family)
Arcobelus Sachs, 1967 † (basis of record)
Arenifodiens Wilson, 2006 (verified source for family)
Argeneuthria Pastorino, 2016 (verified source for family)
Argentinites Baldis & Rossi De Garcia, 1975 † (basis of record)
Argentinobolbina Baldis & Rossi De Garcia, 1975 † (basis of record)
Aristerospira Ehrenberg, 1858 (status source)
Armenocerithium Egoyan, 1955 † (current name source)
Armenocerithium Egoyan, 1955 † (verified source for family)
Arpolyphragmoum Rhumbler, 1913 † accepted as Coscinophragma Thalmann, 1951 † (source of synonymy)
Arribazona Kues, 1990 † (verified source for family)

 Taxonomic remark

 for Aktschagylia Starobogatov, 1970

replacement name for Mactra Ali-Zade, 1967 (nec Linnaeus, 1767) [details]

 Taxonomic remark

 for Chavanella Jaworski in Schindewolf, 1939 †

replacement name for Eomiodon Chavan, 1936 (nec Cox, 1935) [details]

 Taxonomic remark

 for Pseudobrania San Martín, 1984

name proposed in an unpublished thesis [details]

 Taxonomic remark

 for Scolodens Baker, 1956

replacement name for Stenopus Guilding, 1828 (nec Latreille, 1819)  [details]