Abadehella Okimura & Ishii in Okimura, Ishii & Nakazawa, 1975 † (verified source for family)
Abdounodus Gheerbrant & Sudre, 2001 † (verified source for family)
Aberia Melou, 1990 † (verified source for family)
Abertella Durham, 1953 † (verified source for family)
Abichites Shevyrev, 1965 † (verified source for family)
Abrachlamys Beu & Darragh, 2001 † (verified source for family)
Abrekia Dagis, 1974 † (verified source for family)
Abruptolopha Vialov, 1936 † (verified source for family)
Absenticosta Lazarev, 1991 † (verified source for family)
Abuqatrania Simons, Seiffert, Chatrath & Attia, 2002 † (verified source for family)
Abylea Sturgeon, 1964 † (verified source for family)
Acaciapora Moore & Jeffords, 1945 † (verified source for family)
Acadiella Sues & Baird, 1998 † (verified source for family)
Acaenasuchus Long & Murry, 1995 † (verified source for family)
Acaeniotyle Foreman, 1973 † (verified source for family)
Acaeniotylopsis Kito & de Wever, 1994 † (verified source for family)
Acallomyia Melander, 1927 (verified source for family)
Acamptogenotia Rovereto, 1899 † (verified source for family)
Acanthambonia Cooper, 1956 † (verified source for family)
Acanthatia Muir-Wood & Cooper, 1960 † (verified source for family)
Acanthinites Mojsisovics, 1893 † (verified source for family)
Acanthobotrys Popofsky, 1913 (verified source for family)
Acanthoceratites Schrammen, 1928 † (verified source for family)
Acanthocircus Squinabol, 1903 † (verified source for family)
Acanthocoenia d'Orbigny, 1850 † (verified source for family)
Acanthocoryna Finks, 1960 † (verified source for family)
Acanthocosta Roberts, 1971 † (verified source for family)
Acanthogyra Ogilvie, 1897 † (verified source for family)
Acanthohoplites Sinzow, 1907 † (verified source for family)
Acantholytoceras Spath, 1923 † (verified source for family)
Acanthonautilus Foord, 1896 † (verified source for family)
Acanthonema Grabau, 1909 † (verified source for family)
Acanthoplecta Muir-Wood & Cooper, 1960 † (verified source for family)
Acanthoproductus Martynova, 1970 † (verified source for family)
Acanthorthis Neuman, 1976 † (verified source for family)
Acanthoscaphites Nowak, 1911 † (verified source for family)
Acanthospirifer Menakova, 1964 † (verified source for family)
Acanthospirina Schuchert & Le Vene, 1929 † (verified source for family)
Acanthothyropsis Kamyshan in Kamyshan & Babanova, 1973 † (verified source for family)
Acareorthis Roberts in Roberts & Jell, 1990 † (verified source for family)
Acarictis Gingerich & Deutsch, 1989 † (verified source for family)
Acartophthalmites Hennig, 1965 † (verified source for family)
Accidenticulabrum Vermeij, 2000 † (verified source for family)
Acdalopora Bondarenko, 1958 † (verified source for family)
Achelousaurus Sampson, 1995 † (verified source for family)
Acheronictis Hayes, 2000 † (verified source for family)
Acherontiscus Carroll, 1969 † (verified source for family)
Achguigites Klug, 2002 † (verified source for family)
Aciculiscala Sohl, 1963 † (verified source for family)
Aciculolenus Palmer, 1965 † (verified source for family)
Acidiphorus Raymond, 1925 † (verified source for family)
Acidomomys Bloch, Boyer, Gingerich & Gunnell, 2002 † (verified source for family)
Acilia Koken, 1896 † (verified source for family)
Acinetaster Kesling, 1982 † (verified source for family)
Acinophyllum McLaren, 1959 † (verified source for family)
Aciprion Cope, 1873 † (verified source for family)
Acleistoceras Hyatt, 1884 † (verified source for family)
Aclisina Koninck, 1881 † (verified source for family)
Aclistoceras Ruzhentsev, 1975 † (verified source for family)
Acmarhachis Resser, 1938 † (verified source for family)
Acoelia Wu, 1991 † (verified source for family)
Acolosia Cooper & Grant, 1976 † (verified source for family)
Acompsoceras Hyatt, 1903 † (verified source for family)
Acompsosaurus Mehl, 1915 † (verified source for family)
Acorylus Olsson & Harbison, 1953 (verified source for family)
Acosmostroma Stock in Stock & Burry-Stock, 1998 † (verified source for family)
Acriclymenia Bogoslovskii, 1975 † (verified source for family)
Acrimeroceras Beck, 1993 † (verified source for family)
Acrioceras Hyatt in Eastman-Zittel, 1900 † (verified source for family)
Acritosia Cooper & Grant, 1969 † (verified source for family)
Acrocanites Schindewolf, 1922 † (verified source for family)
Acrocyathus d'Orbigny, 1849 † (verified source for family)
Acrophyllum Thomson & Nicholson, 1876 † (verified source for family)
Acropithecus Ameghino, 1903 † (verified source for family)
Acroplous Hotton, 1959 † (verified source for family)
Acropyge Qian, 1977 † (verified source for family)
Acrosolarium Koken, 1896 † (verified source for family)
Acrotemnus Agassiz, 1836 † (verified source for family)
Acrotitan Ye, 1983 † (verified source for family)
Acrotretella Ireland, 1961 † (verified source for family)
Acteosaurus Meyer, 1860 † (verified source for family)
Actinacis d'Orbigny, 1849 † (verified source for family)
Actinaraea d'Orbigny, 1849 † (verified source for family)
Actinaraeopsis Roniewicz, 1968 † (verified source for family)
Actinhelia d'Orbigny, 1849 † (verified source for family)
Actinocrinites Miller, 1821 † (verified source for family)
Actinodiscus Smith & Paul, 1982 † (verified source for family)
Actinodon Gaudry, 1867 † (verified source for family)
Actinomorpha Flower, 1943 † (verified source for family)
Actinophlebia Handlirsch, 1906 † (verified source for family)
Actinophrentis Fomitchev, 1953 † (verified source for family)
Actinopora Vinassa de Regny, 1918 † (verified source for family)
Actinostreon Bayle, 1878 † (verified source for family)
Actinostromarianina Lecompte, 1952 † (verified source for family)
Actinostromina Germovšek, 1954 † (verified source for family)
Acuminothyris Roberts, 1963 † (verified source for family)
Acutatheca Stainbrook, 1945 † (verified source for family)
Acutella Lyashenko, 1973 † (verified source for family)
Acuticassis Dumitrica & Zügel, 2003 † (verified source for family)
Acutichiton Hoare, Sturgeon & Hoare, 1972 † (verified source for family)