Aachenosaurus G. Smets, 1887 † accepted as Nicolia Unger in Endlicher, 1842 † (basis of record)
Abacum M.A. Fombella, 1978 † (basis of record)
Abadehella Okimura & Ishii in Okimura, Ishii & Nakazawa, 1975 † (basis of record)
Abakanicyathus Konyushkov in Zhuravleva, Konyushkov & Rozanov, 1964 † (basis of record)
Abakanopleura Sivov in Khalfin, 1955 † (basis of record)
Abakolia Bognibova in Bognibova & Shcheglov, 1970 † (basis of record)
Abala Handlirsch in Schroeder, 1924 † (basis of record)
Abanaxipha Vickery & Poinar, 1994 † (basis of record)
Abantiadinus Schenkling in Schenkling & Marshall, 1929 (basis of record)
Abathstoma Berger in Lynn, 1979 (basis of record)
Abbelloides Brèthes in de Azevedo Marques, 1928 accepted as Pterygogramma Perkins, 1906 (basis of record)
Abbrosoga Caldwell in Caldwell & Martorell, 1951 (basis of record)
Abderina Seidlitz in Erichson, 1898 (basis of record)
Abdiunguis Park & Wagner in Hatch, 1962 (basis of record)
Abelodon Brunet, Coppens, Dejax, Flynn et al., 1990 † (basis of record)
Abelspora Azevedo, 1987 (basis of record)
Aberdareleria Woznica, 1993 (basis of record)
Abethas Zimmerman in Alonso-Zarazaga & Lyal, 1999 (basis of record)
Abietinella Levinsen, 1913 (basis of record)
Abirus Chapuis in Lacordaire, 1874 (basis of record)
Abjapyx Silvestri, 1948 (basis of record)
Aboriginella Koneva in Koneva & Popov, 1983 † (basis of record)
Aboriginesia Kudryashova, 1993 accepted as Xinjiangsha Wen & Shao, 1984 (basis of record)
Abothrogonia Yang in Yang & Li, 1980 (basis of record)
Abramovia Baranov in Alekseeva, Sidjachenko, Baranov, Afanaseva, Grunt, Komarov, Lazarev & Manankov, 1996 † (basis of record)
Abratopdinium S. Mao & B.A.R. Mohr, 1992 † (basis of record)
Abrobairdia Chen in Chen & Shi, 1982 † (basis of record)
Abrocythereis Gou in Gou, Zheng & Huang, 1983 † (basis of record)
Abrosoma Redtenbacher in Brunner & Redtenbacher, 1906 (basis of record)
Abrota Moore in Horsfield & Moore, 1857 (basis of record)
Abrotus Dolin in Dolin & Pritykina, 1980 † (basis of record)
Absidaticonus Yue in Xing, Ding, Luo, He & Wang, 1984 † (basis of record)
Absonus González-Sponga, 1987 (basis of record)
Abyssameira Itô, 1983 accepted as Argestes G.O. Sars, 1910 (basis of record)
Acablasa Argaman in Argaman & Ozbek, 1992 (basis of record)
Acacidiplosis Gagné in Gagné & Marohasy, 1993 (basis of record)
Acacnitus Say in Keating, 1825 accepted as Acaenitus Latreille, 1809 (basis of record)
Acacus Brunner in Brunner & Redtenbacher, 1907 (basis of record)
Acaenolithus M. Black, 1973 † (basis of record)
Acaenotus Nagatomi & Yanagida in Nagatomi Liu & Yanagida, 1994 (basis of record)
Acalanthis Erichson in Germar, 1844 (basis of record)
Acalia Guenée in Duponchel, 1845 accepted as Lignyoptera Lederer, 1853 (basis of record)
Acalycigorgia Kükenthal in Kükenthal & Gorzawsky, 1908 accepted as Acanthogorgia Gray, 1857 (basis of record)
Acanonicus Westwood in Hope, 1842 (basis of record)
Acanopsilus Kieffer in André, 1908 (basis of record)
Acanosema Kieffer in André, 1908 (basis of record)
Acanthacaris Spence Bate, 1888 (basis of record)
Acanthalepis M'Coy in Griffith, 1846 † (basis of record)
Acanthaspongia M'Coy in Griffith, 1846 † (basis of record)
Acanthephyra A. Milne-Edwards, 1881 (basis of record)
Acanthinopus Pinna, 1974 † (basis of record)
Acanthinotus Swainson in Richardson, 1831 (basis of record)
Acanthinus de La Ferté-Sénectère in Guérin-Méneville, 1849 (basis of record)
Acanthispa Chapuis in Lacordaire & Chapuis, 1875 accepted as Acanthodes Baly, 1864 (basis of record)
Acanthobrama Heckel in Russegger, 1843 (basis of record)
Acanthocarpus Stimpson, 1871 (basis of record)
Acanthocelides Schilsky in Kuester, 1905 accepted as Acanthoscelides Schilsky in Kuester, 1905 (basis of record)
Acanthochaetes Gray in Dieffenbach, 1843 (basis of record)
Acanthochiasma Krohn in Haeckel, 1861 (basis of record)
Acanthochrysis W. Conrad, 1931 accepted as Chromulina L. Cienkowsky, 1870 (basis of record)
Acanthoclymenia Hyatt in Eastman-Zittel, 1900 † (basis of record)
Acanthocnema A. Costa in O. Costa, 1859 (basis of record)
Acanthocnemis Blanchard in Gay, 1852 (basis of record)
Acanthocnemoides Zherichin in Zherikhin, 1977 † (basis of record)
Acanthocolpus Lühe in Herdman, 1906 (basis of record)
Acanthoconia Sollas in Harmer & Shipley, 1906 † accepted as Ischadites R.I. Murchison, 1839 † (basis of record)
Acanthocotyle Monticelli in Saggio, 1888 (basis of record)
Acanthocyclus Lucas in H. Milne Edwards & Lucas, 1844 (basis of record)
Acanthodes De Haan in Siebold, 1833 † accepted as Hypothalassia Gistel, 1848 (basis of record)
Acanthodesia Canu & Bassler, 1919 accepted as Biflustra d'Orbigny, 1852 (basis of record)
Acanthodictya Hinde in Dawson & Hinde, 1889 † (basis of record)
Acanthodinium Kofoid, 1907 (basis of record)
Acanthodis Miller in Absolom, 1933 † (basis of record)
Acanthodoxus Martins & Monné, 1974 (basis of record)
Acanthodromia A. Milne-Edwards, 1880 (basis of record)
Acanthodyta Sharp in Willey, 1898 (basis of record)
Acanthogonyaulax (Kofoid) Graham, 1942 (basis of record)
Acanthoisis Studer, 1887 (basis of record)
Acantholabrus Valenciennes in Cuvier & Valenciennes, 1839 (basis of record)
Acantholepis Pyanovska & Aleksandro in Pyanovskaya, 1989 † (basis of record)
Acantholithodes Holmes, 1894 (basis of record)
Acanthomera Latreille in Cuvier, 1829 accepted as Psorodes Solier in Baudi & Truqui, 1848 (basis of record)
Acanthonotus Swainson in Richardson, 1832 (basis of record)
Acanthonotus Ross in Ross, 1835 accepted as Acanthonotozoma Boeck, 1876 (basis of record)
Acanthonyx Latreille, 1828 (basis of record)
Acanthophis Daudin in Sonnini, 1803 (basis of record)
Acanthophrys A. Milne-Edwards, 1865 (basis of record)
Acanthoplax H. Milne Edwards, 1852 accepted as Uca Leach, 1814 (basis of record)
Acanthopleura Engel in Lindner, 1927 (basis of record)
Acanthopleuroceras Hyatt in Eastman-Zittel, 1900 † (basis of record)
Acanthopsilus Kieffer in André, 1908 (basis of record)
Acanthopsis van Hasselt in Férussac, 1824 accepted as Cobitis Linnaeus, 1758 (basis of record)
Acanthoptera Latreille in Cuvier, 1829 (basis of record)
Acanthopus De Haan, 1833 accepted as Percnon Gistel, 1848 (basis of record)
Acanthopus Latreille in Cuvier, 1829 accepted as Accanthopus Dejean, 1821 (basis of record)
Acanthoscelides Schilsky in Kuester, 1905 (basis of record)
Acanthosoma Ross in Ross, 1835 (basis of record)
Acanthosphaeridium M. Hajós & H. Stradner in M. Hajós, 1975 † (basis of record)
Acanthoteuthis Wagner in Münster, 1839 † (basis of record)
Acanthothecum Rohdendorf in Lindner, 1930 (basis of record)