Stratigraphic time - taxa
genus Aarabia Mey.-Berth. & Gerrienne (Lower Devonian)
species Aarabia brevicaulis Mey.-Berth. & Gerrienne (Emsian)
species Aayemenaytcheia paragranulata (Ormiston, 1967) (Emsian)
species Aberlemnia caledonica (D.Edwards) Gonez & Gerrienne (Lower Devonian)
genus Acanthatia Muir-Wood & Cooper, 1960 (Devonian)
species Acanthograptus lejskoviensis Bouček, 1957 (Lochkovian)
species Acanthophyllum baculoides (Počta, 1902) (Pragian)
genus Acanthoproductus Martynova, 1970 (Devonian)
species Acanthopyge aigaion Vaněk, 2002 (Emsian)
species Acanthopyge docekali (Vaněk, 1959) (Emsian)
species Acanthopyge pervasta Přibyl, Vaněk & Hörbinger, 1986 (Emsian)
species Acanthoscapha navicula (Ulrich, 1891) (Lower Devonian)
species Acanthospongia bohemicum Katzer, 1888 (Lochkovian)
species Acastoides haddadi Chatterton, Fortey, Brett, Gibb & McKellar, 2006 (Emsian)
species Acastoides poschmanni Basse & Müller, 2016 (Emsian)
species Acastoides zguilmensis Chatterton, Fortey, Brett, Gibb & Mckellar, 2006 (Emsian)
species Acrosaccus robustus Mergl & Šmídtová, 2023 (Pragian)
genus Acrospirifer Helmbrecht & Wedekind, 1923 (Devonian)
species Acrotretella triseptata Mergl, 2001 (Lochkovian)
species Actinolepis spinosa Mark-Kurik, 1985 (Lower Devonian)
species Actinolepis zaikai Plax et Newman, 2020 (Emsian)
class Actinopterygii Klein, 1885 - ray-finned fishes (Upper Silurian - recent)
species Actinostroma perspicuum Počta, 1894 (Emsian)
species Actinostroma sertiforme Lecompte, 1951 (Pragian)
genus Acutatheca Stainbrook, 1945 (Devonian)
species Agoniatites praeceps Chlupáč & Turek, 1983 (Emsian)
species Agoniatites uralensis Bogoslovsky, 1969 (Lower Devonian)
species Alaskospira candida (Havlíček, 1959) (Pragian)
species Alberticoryphe albata Přibyl & Vaněk, 1987 (Pragian)
species Alberticoryphe osmal Šnajdr, 1980 (Emsian)
genus Allanicytidium Caster & Gill, 1967 (Devonian)
species Allanicytidium africana (Reed, 1925) (Devonian)
species Allanicytidium flemingi Caster & Gill, 1967 (Lower Devonian)
species Alternifenestella estrellita McKinney & Kříž, 1986 (Emsian)
species Alternifenestella strigilla McKinney & Kříž, 1986 (Pragian)
species Ambocoelia bubovica Mergl, 2003 (Lochkovian)
species Ambocoelia operculifera Havlíček, 1956 (Pragian)
species Ambocoelia pseudoumbonata Kozłowski, 1923 (Devonian)
species Ambocoelia rogeri Drot, 1956 (Devonian)
species Ambocoelia umbonata (Conrad, 1842) (Devonian)
species Ambothyris halli (Branson, 1924) (Devonian)
species Amissopecten leidholdi (Havlíček, 1956) (Emsian)
species Amissopecten obsolescens (Barrande, 1879) (Emsian)
species Ammonicrinus bulbosus Prokop, 2009 (Pragian)
kingdom Amoebozoa Lühe, 1913 emend. Cavalier-Smith, 1998 (Neoproterozoic - recent)
species Amoenophyllites amoenus (Barrande, 1865) (Emsian)
subspecies Amoenospirifer thetidis amoenus (Havlíček, 1956) (Emsian)
subspecies Amoenospirifer thetidis thetidis (Barrande, 1848) (Pragian)
species Anarcestes applanatus Frech, 1895 (Emsian)
species Anarcestes densistriatus Chlupáč & Turek, 1983 (Emsian)
species Anarcestes lateseptatus (Beyrich, 1837) (Emsian)
species Anarcestes latissimus Chlupáč & Turek, 1983 (Emsian)
species Anarcestes plebeius (Barrande, 1865) (Emsian)
species Anarcestes simulans (Barrande, 1865) (Emsian)
species Andegavia titya (Šnajdr, 1989) (Emsian)
species Andenothyone gondwanensis Haude, 1995 (Lower Devonian)
species Anetoceras elegantulum (Shen, 1975) (Lower Devonian)
species Anetoceras ellipticum (Shen, 1975) (Lower Devonian)
species Anetoceras erbeni (House, 1965) (Lower Devonian)
species Anetoceras kimi Bogoslovsky, 1980 (Lower Devonian)
species Anetoceras oriens Chlupáč & Turek, 1983 (Emsian)
species Anetoceras rareplicatum (Ruan & He, 1974) (Lower Devonian)
species Anetoceras solitarium (Barrande, 1865) (Emsian)
species Angeisonoceras davidsoni (Barrande, 1870) (Lochkovian)
species Angeisonoceras reteornatum Kröger, 2008 (Pragian)
species Anomalocystites disparilis Hall, 1859 (Devonian)
species Anomalotoechus typicus Duncan, 1939 (Pragian)
species Antineosteus rufus Vaškaninová & Kraft, 2014 (Emsian)
species Aphyctoceras annulatum (Barrande, 1865) (Pragian)
species Areostrophia interjecta (Barrande, 1879) (Lochkovian)
species Areostrophia nigra Havlíček, 1967 (Lochkovian)
species Argentinaster bodenbenderi Ruedemann, 1916 (Lower Devonian)
species Arionoceras kennethdebaetsi Frey, Naglik, Hofmann, Schemm-Gregory, Frýda, Kröger, Taylor, Wilson & Klug, 2014 (Pragian)
species Aristozoe amica Barrande, 1872 (Pragian)
species Aristozoe barborae Chlupáč, 1992 (Lochkovian)
species Aristozoe bisulcata Barrande, 1872 (Pragian)
species Aristozoe bulbosa Chlupáč, 1992 (Pragian)
species Aristozoe clarkei Perner, 1916 (Lochkovian)
species Aristozoe lepida Barrande, 1872 (Pragian)
species Aristozoe memoranda Barrande, 1872 (Pragian)
species Aristozoe orphana Barrande, 1872 (Pragian)
species Aristozoe parabolica Perner, 1916 (Lochkovian)
species Aristozoe peckai Chlupáč, 1992 (Lochkovian)