Aachenaspis Egerton, 1857 † accepted as Auchenaspis Egerton, 1857 † (source of synonymy)
Aaglacrinus † accepted as Aglaocrinus Strimple, 1961 † (source of synonymy)
Aagyrus accepted as Anagyrus Howard, 1896 (source of synonymy)
Aalolana accepted as Aatolana Bruce, 1993 (source of synonymy)
Abaciidae † accepted as Arbaciidae Gray, 1855 (source of synonymy)
Abaræus Jordan, 1903 accepted as Abaraeus Jordan, 1903 (source of synonymy)
Abax Stephens, 1827 accepted as Abax Bonelli, 1810 (source of synonymy)
Abergasilis accepted as Abergasilus Hewitt, 1978 (source of synonymy)
Abiscodiaspis accepted as Adiscodiaspis Marchal, 1909 (source of synonymy)
Abracadbrella accepted as Abracadabrella Zabka, 1991 (source of synonymy)
Abralia astrostricta Berry, 1909 accepted as Abralia astrosticta Berry, 1909 (source of synonymy)
Abrallaspis accepted as Abgrallaspis Balachowsky, 1948 (source of synonymy)
Abrotrocha accepted as Habrotrocha Bryce, 1910 (source of synonymy)
Abrytasites † accepted as Abrytusites Nikolov & Breskovski, 1969 † (source of synonymy)
Absalomichthyes † accepted as Absalomichthys Whitley, 1933 † (source of synonymy)
Äbudefduf Forskål, 1775 accepted as Abudefduf Forsskål, 1775 (source of synonymy)
Abyssinoe [auct.] accepted as Abyssoninoe Orensanz, 1990 (source of synonymy)
Acabaria erythaea accepted as Acabaria erythraea (Ehrenberg, 1834) (source of synonymy)
Acaemops accepted as Acmaeops Leconte, 1850 (source of synonymy)
Acaltes accepted as Acalles Schönherr, 1825 (source of synonymy)
Acandylacanthus † accepted as Acondylacanthus St. John & Worthen, 1875 † (source of synonymy)
Acanopterus accepted as Aconopterus Blanchard in Gay, 1851 (source of synonymy)
Acanothyra † accepted as Acanothyia Pomel, 1872 † (source of synonymy)
Acansozostera accepted as Acanthozostera Iredale & Hull, 1926 accepted as Acanthopleura Guilding, 1829 (source of synonymy)
Acanthaeshna accepted as Acanthaeschna Selys, 1883 (source of synonymy)
Acanthapsis accepted as Acanthaspis Amyot & Serville, 1843 (source of synonymy)
Acanthasterella † accepted as Acanthastrella Schrammen, 1924 † (source of synonymy)
Acanthetaxalus accepted as Acanthetaxulus Breuning, 1960 (source of synonymy)
Acanthobatididae accepted as Anacanthobatidae (source of synonymy)
Acanthoceros accepted as Acanthoceras H. Honigmann, 1909 (source of synonymy)
Acanthocistidae accepted as Acanthocystidae Claus, 1874 (source of synonymy)
Acanthodres accepted as Acanthoderes Audinet-Serville, 1835 (source of synonymy)
Acanthoecaceae accepted as Acanthoecidae Norris, 1965 (source of synonymy)
Acantholepis † accepted as Acanthalepis M'Coy in Griffith, 1846 † (source of synonymy)
Acanthophillia † accepted as Acanthophyllia Wells, 1937 accepted as Cynarina Brüggemann, 1877 (source of synonymy)
Acanthoplegmatidae accepted as Acanthoplegmidae Schewiakoff, 1926 (source of synonymy)
Acanthoporidea † accepted as Acanthoporidra Davis, 1934 † (source of synonymy)
Acanthosperma Vellozo, 1831 accepted as Acantho-sperma Vellozo, 1831 (source of synonymy)
Acanthotrophia † accepted as Acanthostrophia Conti & Fischer, 1984 † (source of synonymy)
Acantocybium accepted as Acanthocybium Gill, 1862 (source of synonymy)
Acantodactylus accepted as Acanthodactylus Wiegmann, 1834 (source of synonymy)
Acantonotella Zaspelova, 1952 † accepted as Acantonodella Zaspelova, 1952 † (source of synonymy)
Accanthomunna accepted as Acanthomunna Beddard, 1886 (source of synonymy)
Acetopeltis † accepted as Ascetopeltis Owens, 1973 † (source of synonymy)
Acheliognathus accepted as Acheilognathus Bleeker, 1859 (source of synonymy)
Achiurus accepted as Achirus Lacepède, 1802 (source of synonymy)
Achmaeops Leconte, 1850 accepted as Acmaeops Leconte, 1850 (source of synonymy)
Achmæops Leconte, 1850 accepted as Acmaeops Leconte, 1850 (source of synonymy)
Achnanthes plœnensis Hustedt accepted as Achnanthes ploenensis Hustedt, 1930 (source of synonymy)
Achnanthes valpestris accepted as Achnanthes deflexa C.W. Reimer, 1966 accepted as Achnanthidium deflexum (C.W. Reimer) J.C. Kingston, 2000 (source of synonymy)
Achnanthidium biasolettiana (Grunow) L. Bukhtiyarova, 1995 accepted as accepted as Achnanthes biasolettiana Grunow, 1880 (source of synonymy)
Achrochordonia † accepted as Acrochordonia Schrammen, 1901 † (source of synonymy)
Acidolobus accepted as Acidilobus Prokofeva et al., 2000 emend. Prokofeva, Kostrikina, Kolganova, Tourova, Lysenko, Lebedinsky & Bonch-Osmolovskaya, 2009 (source of synonymy)
Acidota Stephens, 1834 accepted as Acidota Kirby in Stephens, 1829 (source of synonymy)
Acloeodictya † accepted as Achloeodictya Hall & Clarke, 1898 † (source of synonymy)
Acmæops Leconte, 1850 accepted as Acmaeops Leconte, 1850 (source of synonymy)
Acravincula † accepted as Acravicula Becker in Bandel & Becker, 1975 † (source of synonymy)
Acrochaetium barbadensis (Vickers) Borgesen, 1915 accepted as Acrochaetium barbadense (Vickers) Børgesen, 1915 (source of synonymy)
Acrochaetium codicola Børgesen, 1927 accepted as Acrochaetium codicolum Børgesen, 1927 (source of synonymy)
Acrolepidae accepted as Glyphipterigidae Stainton, 1854 (source of synonymy)
Acromia accepted as Acrocomia C.F.P. Martius, 1824 (source of synonymy)
Acroptilion accepted as Acroptilon Cassini in F. Cuvier, 1827 accepted as Rhaponticum S. Vaillant, 1754 (source of synonymy)
Acroreidae † accepted as Acroreiidae Cossmann, 1893 † (source of synonymy)
Acrosphaerorthoceras † accepted as Akrosphaerorthoceras Ristedt, 1968 (source of synonymy)
Acsaspedites † accepted as Acraspedites Haeckel, 1869 (source of synonymy)
Acticyon Stock, 1947 † accepted as Actiocyon Stock, 1947 † (source of synonymy)
Actinastaeopsis † accepted as Actinastraeopsis Sikharulidze, 1977 † (source of synonymy)
Actinastraea † accepted as Actinastrea d'Orbigny, 1849 (source of synonymy)
Actínia Linnaeus, 1767 accepted as Actinia Linnaeus, 1767 (source of synonymy)
Actiniscus C.G. Ehrenberg, 1840 accepted as Actiniscus Ehrenberg, 1841 (source of synonymy)
Actinolites † accepted as Eiffelia Walcott, 1920 † (source of synonymy)
Actinopsis accepted as Acinopsis Monterosato, 1884 accepted as Alvania Risso, 1826 (source of synonymy)
Actinothoë Fischer, 1889 accepted as Actinothoe Fischer, 1889 (source of synonymy)
Actomphalus † accepted as Arctomphalus Tolmachoff, 1926 † (source of synonymy)
Acutatognostus † accepted as Acutatagnostus Ergaliev, 1980 † (source of synonymy)
Acutilineolus † accepted as Acutilineotus Amsden, 1978 † (source of synonymy)
Adamboë Adanson, 1763 accepted as Adamboe Adanson, 1763 accepted as Lagerstroemia Linnaeus, 1759 (source of synonymy)
Adapium Young, 1937 † accepted as Adapidium Young, 1937 † (source of synonymy)
Adekoheastrea † accepted as Adegokeastrea Ogbe, 1976 † (source of synonymy)
Adekunbiellda † accepted as Adekunbiella Adegoke, 1967 † (source of synonymy)
Adelodonex † accepted as Adelodonax Saul, 1989 † (source of synonymy)
Ademtula accepted as Admetula Cossmann, 1889 (source of synonymy)
Adenoïdes E. Balech, 1956 accepted as Adenoides E. Balech, 1956 (source of synonymy)
Adenus † accepted as Adensu Popov & Rukavishnikova, 1986 † (source of synonymy)
Adkinsites † accepted as Adkimsites Spath, 1931 † (source of synonymy)
Adoncholaimus crassicaudatus Wieser, 1953 accepted as Adoncholaimus crassicaudus Wieser, 1953 (source of synonymy)
Adraheutina † accepted as Adrahentina Bilotte, 1978 † (source of synonymy)
Æchmutes Bates, 1867 represented as Aechmutes Bates, 1867 (source of synonymy)
Aedomone accepted as Aedemone Kotschy, 1858 (source of synonymy)
Aedulla † accepted as Aeduella Westoll, 1937 (source of synonymy)
Aegicephalichthys † accepted as Agecephalichthys Wade, 1935 † (source of synonymy)
Ægir Danielssen, 1888 accepted as Halcampoides Danielssen, 1890 (source of synonymy)
Aegironites † accepted as Aegironetes Havlicek, 1967 † (source of synonymy)
Ægoidus Buquet, 1838 accepted as Aegoidus Buquet, 1838 (source of synonymy)
Ægoïdus Buquet, 1838 accepted as Aegoidus Buquet, 1838 (source of synonymy)
Ægomomus Pascoe, 1864 accepted as Aegomomus. Pascoe, 1864 accepted as Rhytiphora Audinet-Serville, 1835 (source of synonymy)
Ægomorphus Haldeman, 1847 accepted as Aegomorphus Haldeman, 1847 (source of synonymy)
Ægosoma Audinet-Serville, 1832 accepted as Aegosoma Audinet-Serville, 1832 (source of synonymy)
Aehmospira † accepted as Aechmospira Qiao † (source of synonymy)
Ælara Thomson, 1864 accepted as Aelara Thomson, 1864 accepted as Niphona Mulsant, 1839 (source of synonymy)

 Nomenclatural status

 for Heteroserolis Nordenstam, 1933

nomen nudum [details]

 Nomenclatural status

 for Microproctus

orthographia [details]

 Nomenclatural status

 for Microproctus caecus

orthographia [details]

 Nomenclatural status

 for Pananthura

orthographia [details]

 Nomenclatural status

 for Pananthura formosa

orthographia [details]

 Nomenclatural status

 for Parabopyrinella heardi Adkison, 1984

orthographia [details]

 Nomenclatural status

 for Parabopyrinella latreuticola (Gissler, 1882)

orthographia [details]

 Nomenclatural status

 for Probopyris

orthographia [details]

 Nomenclatural status

 for Probopyris bithynis Richardson, 1904

orthographia [details]

 Nomenclatural status

 for Thaumostoma

orthographia [details]

 Nomenclatural status

 for Thaumostoma platycarpus

orthographia [details]

 Taxonomic remark

 for Agapophyta Laporte, 1832

Listed as a new name in Nomenclator Zoologicus, however on the cited page 63 of Laporte's work the name is ... [details]

 Taxonomic remark

 for Heteroserolis Nordenstam, 1933

A nomen nudum, subsequently validly published by Brandt, 1991. [details]

 Taxonomic remark

 for Ostodolepididae Romer, 1945 †

Spelling Ostodolepididae is technically correct, however Ostodolepidae is in current usage e.g. in PaleoBiology ... [details]

 Taxonomic remark

 for Sandownidae Tong & Meylan, 2013 †

Original spelling Sandownidae is incorrectly formed (type genus is Sandownia), mandatory correction is to ... [details]

 Taxonomic remark

 for Xiphiozona Berry, 1919 [2]

Berry appears to have described this taxon (a subgenus of Leptochiton) as new twice in the same year, first in ... [details]