Aachenaspis Egerton, 1857 † accepted as Auchenaspis Egerton, 1857 † (name verified source)
Aaglacrinus † accepted as Aglaocrinus Strimple, 1961 † (name verified source)
Aagyrus accepted as Anagyrus Howard, 1896 (name verified source)
Aalolana accepted as Aatolana Bruce, 1993 (name verified source)
Abergasilis accepted as Abergasilus Hewitt, 1978 (name verified source)
Abrytasites † accepted as Abrytusites Nikolov & Breskovski, 1969 † (name verified source)
Absalomichthyes † accepted as Absalomichthys Whitley, 1933 † (name verified source)
Acandylacanthus † accepted as Acondylacanthus St. John & Worthen, 1875 † (name verified source)
Acanothyra † accepted as Acanothyia Pomel, 1872 † (name verified source)
Acantholepis † accepted as Acanthalepis M'Coy in Griffith, 1846 † (name verified source)
Acanthophillia † accepted as Acanthophyllia Wells, 1937 accepted as Cynarina Brüggemann, 1877 (name verified source)
Acanthoporidea † accepted as Acanthoporidra Davis, 1934 † (name verified source)
Acanthotrophia † accepted as Acanthostrophia Conti & Fischer, 1984 † (name verified source)
Acetopeltis † accepted as Ascetopeltis Owens, 1973 † (name verified source)
Achiurus accepted as Achirus Lacepède, 1802 (name verified source)
Achrochordonia † accepted as Acrochordonia Schrammen, 1901 † (name verified source)
Acloeodictya † accepted as Achloeodictya Hall & Clarke, 1898 † (name verified source)
Acravincula † accepted as Acravicula Becker in Bandel & Becker, 1975 † (name verified source)
Acrosphaerorthoceras † accepted as Akrosphaerorthoceras Ristedt, 1968 (name verified source)
Acrothyris Hou, 1963 † (name verified source)
Acsaspedites † accepted as Acraspedites Haeckel, 1869 (name verified source)
Actinastaeopsis † accepted as Actinastraeopsis Sikharulidze, 1977 † (name verified source)
Actinastraea † accepted as Actinastrea d'Orbigny, 1849 (name verified source)
Actinopsis accepted as Acinopsis Monterosato, 1884 accepted as Alvania Risso, 1826 (name verified source)
Actomphalus † accepted as Arctomphalus Tolmachoff, 1926 † (name verified source)
Acutatognostus † accepted as Acutatagnostus Ergaliev, 1980 † (name verified source)
Acutilineolus † accepted as Acutilineotus Amsden, 1978 † (name verified source)
Adekoheastrea † accepted as Adegokeastrea Ogbe, 1976 † (name verified source)
Adekunbiellda † accepted as Adekunbiella Adegoke, 1967 † (name verified source)
Adelodonex † accepted as Adelodonax Saul, 1989 † (name verified source)
Ademtula accepted as Admetula Cossmann, 1889 (name verified source)
Adenus † accepted as Adensu Popov & Rukavishnikova, 1986 † (name verified source)
Adkinsites † accepted as Adkimsites Spath, 1931 † (name verified source)
Adraheutina † accepted as Adrahentina Bilotte, 1978 † (name verified source)
Aedulla † accepted as Aeduella Westoll, 1937 † (name verified source)
Aegicephalichthys † accepted as Agecephalichthys Wade, 1935 † (name verified source)
Aegironites † accepted as Aegironetes Havlicek, 1967 † (name verified source)
Aehmospira † accepted as Aechmospira Qiao † (name verified source)
Aerithyris † accepted as Agerithyris Radulovic, 1991 † (name verified source)
Aethoceras † accepted as Aethocera Teichert & Glenister, 1954 † (name verified source)
Aethodionide † accepted as Aethedionide Zhou & Ju, 1983 † (name verified source)
Affrollonia † accepted as Afrollonia Adegoke, 1977 † (name verified source)
Afganodesma † accepted as Afghanodesma Termier & Termier in Desparmet, Termier & Termier, 1971 † (name verified source)
Aficanaspis † accepted as Africanaspis Long, Anderson, Gess & Hiller, 1997 † (name verified source)
Agasso † accepted as Agaso Cobbold, 1934 † (name verified source)
Agathiphyllia † accepted as Agathyphyllia Reuss, 1864 (name verified source)
Agnostaridis † accepted as Agnostardis Öpik, 1963 † (name verified source)
Aikenicythere † accepted as Aitkenicythere Bate, 1976 † (name verified source)
Ajirikina † accepted as Ajrikina Krys'kov in Borovikov & Krys'kov, 1963 † (name verified source)
Alabusherothyris † accepted as Alabushevothyris Smirnova, 1994 † (name verified source)
Albebarania † accepted as Aldebarania Blake & Sturgeon, 1995 † (name verified source)
Aldaniopirifer † accepted as Aldanispirifer Alekseeva, 1967 † (name verified source)
Algerina † accepted as Algeriana Majoran, 1989 † (name verified source)
Aliporus accepted as Haliporus Spence Bate, 1881 (name verified source)
Alkaida † accepted as Alkaidia Blake & Reid, 1998 † (name verified source)
Allelepidotus † accepted as Allolepidotus Deecke, 1889 † (name verified source)
Allophyllognathus accepted as Allophyllognathopus Kiefer, 1967 (name verified source)
Allopontia accepted as Allopontonia Bruce, 1972 (name verified source)
Allotropiophyllum † accepted as Allotrophiophyllum Grabau, 1928 † (name verified source)
Alokistokaropsis † accepted as Alokistocaropsis Repina in Musatov, 1965 † (name verified source)
Alpheaus accepted as Alpheus Fabricius, 1798 (name verified source)
Altaesajanis † accepted as Altaesajania Maksimova, 1978 † (name verified source)
Altaiophyllum † accepted as Alaiophyllum Ghoryanov, 1961 † (name verified source)
Cayastria † accepted as Cayastaia Rusconi, 1954 † (name verified source)
Cotylidea accepted as Cotylidia P. Karsten, 1881 (name verified source)
Diamena Dahlbom, 1844 accepted as Cerceris Latreille, 1802 (status source)
Hydrocoleus accepted as Hydrocoleum Kützing ex Gomont, 1892 (name verified source)
Saurichthyes † accepted as Saurichthys Agassiz, 1834 † (name verified source)
Sïlenocoenia † accepted as Solenocoenia Roniewicz & Gill in Roniewicz, 1976 † (name verified source)
Waeringscorpii Sepkoski, 2002 † accepted as Waeringoscorpio Størmer, 1970 † (name verified source)
Yarella accepted as Yarrella Goode & Bean, 1896 (name verified source)
Zabrasoma accepted as Zebrasoma Swainson, 1839 (name verified source)