Stratigraphic time - taxa
genus Abia Leach, 1817 (Middle Miocene - recent)
section Abies (Piacenzian - recent)
genus Abies Mill. - fir (Hauterivian - recent)
species Abies alba Mill. - European Silver Fir (Piacenzian - recent)
species Abies concolor (Gordon & Glend.) Lindl. ex Hildebr. - White Fir (Pleistocene - recent)
species Abies delavayi Franch. - Delavay's Fir (Pliocene - recent)
species Abies firma Siebold & Zucc. - Momi Fir (Pliocene - recent)
species Abies homolepis Siebold & Zucc. - Nikko Fir (Pleistocene - recent)
subfamily Abietoideae Lindl. Emend Pilger & Melchior (Hauterivian - recent)
genus Abyssothyris Thomson, 1927 (Tertiary - recent)
subgenus Acallomyia Melander, 1927 (Oligocene - recent)
legio Acalyptratae Macquart, 1835 (Upper Eocene - recent)
tribus Acanthocinini Blanchard, 1845 (Chattian - recent)
subgenus Acanthocinus Dejean, 1821 (Piacenzian - recent)
genus Acanthocinus Dejean, 1821 (Piacenzian - recent)
tribus Acanthoderini Thomson, 1860 (Rupelian - recent)
genus Acanthosoma Curtis, 1824 (Middle Miocene - recent)
species Acer campestre L. - Field Maple (Piacenzian - recent)
infraorder Achelata Scholtz & Richter, 1995 (Lower Triassic - recent)
tribus Achrysonini Lacordaire, 1869 (Rupelian - recent)
suborder Acipenseroidei (Upper Cretaceous - recent)
species Aclypea altaica (Gebler, 1830) (Gelasian - recent)
species Aclypea bituberosa (LeConte, 1859) - Western Spinach Carrion Beetle (Upper Pleistocene - recent)
species Aclypea calva (Reitter, 1885) (Upper Pleistocene - recent)
species Aclypea opaca (Linnaeus, 1758) - Beet Carrion Beetle (Upper Pleistocene - recent)
species Aclypea sericea (Zoubkoff, 1833) (Upper Pleistocene - recent)
family Acrididae MacLeay, 1821 - short horned grasshoppers (Serravallian - recent)
genus Acrobrochus Cooper, 1983 (Tertiary - recent)
family Acrochordidae Bonaparte, 1831 - wart snakes (Middle Miocene - recent)
genus Acrossus Mulsant, 1842 (Piacenzian - recent)
species Acrossus rufipes (Linnaeus, 1758) (Piacenzian - recent)
superorder Actinistia (Middle Devonian - recent)
class Actinopterygii Klein, 1885 - ray-finned fishes (Upper Silurian - recent)
suborder Adephaga Schellenberg, 1806 (Hettangian - recent)
genus Aegomorphus Haldeman, 1847 (Rupelian - recent)
genus Aelia Fabricius, 1803 (Serravallian - recent)
tribus Aelini Douglas & Scott, 1865 (Serravallian - recent)
subfamily Aesalinae MacLeay, 1819 (Cenomanian - recent)
tribus Aesalini MacLeay, 1819 (Upper Cretaceous - recent)
family Agamidae Gray, 1827 - agamas (Upper Cretaceous - recent)
genus Agonum Bonelli, 1810 (Upper Pleistocene - recent)
species Agonum chalconotum Ménétriés, 1832 (Upper Pleistocene - recent)
species Agonum ferruginosum (Dejean, 1828) (Upper Pleistocene - recent)
species Agonum micans (Nicolai, 1822) (Upper Pleistocene - recent)
species Agonum muelleri (Herbst, 1784) (Chibanian - recent)
species Agonum sexpunctatum (Linnaeus, 1758) (Upper Pleistocene - recent)
species Agonum versutum Sturm, 1824 (Upper Pleistocene - recent)
subfamily Agrypninae Candèze, 1857 (Cenomanian - recent)
species Agrypnus unicolor (Hope, 1837) (Holocene)
genus Alavesia Waters & Arillo, 1999 (Cenomanian - recent)
genus Alca Linnaeus, 1758 (Upper Miocene - recent)
subfamily Aleuropteryginae (Callovian - recent)
tribus Allandrini Pierce, 1930 (Rupelian - recent)
subtribus Alleculina Seidlitz, 1836 (Priabonian - recent)
subfamily Alleculinae Seidlitz, 1836 - Comb-clawed Beetles (Rupelian - recent)
tribus Alleculini Seidlitz, 1836 (Rupelian - recent)
family Alligatoridae Gray, 1844 (Upper Cretaceous - recent)
species Alnus incana (L.) Moench - Grey Alder (Piacenzian - recent)
section Amabilis (Burdigalian - recent)
genus Amartus LeConte, 1861 (Priabonian - recent)
tribus Amarygmini Gistel, 1848 (Priabonian - recent)
genus Amblyteles Wesmael, 1844 (Priabonian - recent)
family Ambystomatidae Gray, 1850 (Rupelian - recent)
order Ambystomatoidea (Upper Cretaceous - recent)
family Amiidae Bonaparte, 1831 - bowfins (Upper Jurassic - recent)
order Amiiformes Hay, 1929 - bowfins (Lower Triassic - recent)
subfamily Amnestinae Hart, 1919 (Aptian - recent)
genus Amnestus Dallas, 1851 (Aquitanian - recent)
kingdom Amoebozoa Lühe, 1913 emend. Cavalier-Smith, 1998 (Neoproterozoic - recent)
family Amorphoscelidae Stål, 1877 (Aptian - recent)
subfamily Amorphoscelinae Stål, 1877 (Aptian - recent)
tribus Amorphoscelini Stål, 1877 (Aptian - recent)
tribus Amphidorini LeConte, 1862 (Piacenzian - recent)
family Amphisbaenidae Gray, 1865 - worm lizards (Upper Eocene - recent)
family Amphiumidae Garden in Smith, 1821 - amphiumas (Upper Cretaceous - recent)
order Amphiumoidea (Upper Cretaceous - recent)
tribus Anaglyptini Lacordaire, 1868 (Rupelian - recent)
subfamily Anaidinae Nikolajev, 1996 (Lower Cretaceous - recent)
tribus Ancyronini Kolibáč, 2006 (Eocene - recent)