Aachenosaurus Smets Abelisaurus  Abrictosaurus Abrosaurus Ouyang  Acanthopholis  Achelousaurus  Achillobator  Acrocanthosaurus Actiosaurus  Adasaurus  Aegyptosaurus Aepisaurus Aetonyx Broom Afrovenator Sereno  Aeolosaurus  Afrovenator  Agilisaurus   Alamosaurus  Albertosaurus  Alectrosaurus  Algoasaurus  Alioramus  Allosaurus  Alxasaurus  Amargasaurus

Agathaumas Cope, 1872
Aggiosaurus Ambayrac, 1913*
Agilisaurus Peng, 1990
Agrosaurus Seeley, 1891
Agustinia Bonaparte, 1999
Alamosaurus Gilmore, 1922
Albertosaurus Osborn, 1905
Albisaurus Fritsch, 1905*
Alectrosaurus Gilmore, 1933
Algoasaurus Broom, 1904
Alioramus Kurzanov, 1976
Aliwalia Galton, 1985
Allosaurus Marsh, 1877
Alocodon Thulborn, 1973
Altirhinus Norman, 1998
Altispinax von Huene, 1923
Alvarezsaurus Bonaparte, 1991
Alwalkeria Chatterjee & Creisler, 1994
Alxasaurus Russell & Dong, 1994 (not 1993)
Amargasaurus Salgado & Bonaparte, 1991
Ammosaurus Marsh, 1891
Ampelosaurus Le Loeuff, 1995
Amphicoelias Cope, 1877
Amphisaurus Marsh, 1882/Barkas, 1870
Amtosaurus Kurzanov & Tumanova, 1978
Amurosaurus Bolotsky & Kurzanov, 1991
Amygdalodon Cabrera, 1947
Anabisetia Coria & Calvo vide Coria, 1999 [nomen nudum]
Anasazisaurus Hunt & Lucas, 1993
Anatosaurus Lull & Wright, 1942
Anatotitan Brett-Surman vide Chapman & Brett-Surman, 1990
Anchiceratops Brown, 1914
Anchisaurus Marsh, 1885
Andesaurus Calvo & Bonaparte, 1991
Angaturama Kellner & Campos, 1996
Animantarx Carpenter, Kirkland, Burge & Bird, 1999
Ankistrodon Huxley, 1865*
Ankylosaurus Brown, 1908
Anodontosaurus C. M. Sternberg, 1929
Anoplosaurus Seeley, 1879
Anserimimus Barsbold, 1988
Antarctosaurus von Huene, 1929
Anthodon Owen, 1876*
Antrodemus Leidy, 1870
Apatodon Marsh, 1877
Apatosaurus Marsh, 1877
Aragosaurus Sanz, Buscalioni, Casanovas & Santafe, 1987
Aralosaurus Rozhdestvensky, 1968
Araucanoraptor Novas, 1997 [nomen nudum]
Archaeoceratops Dong & Azuma, 1997
Archaeopteryx von Meyer, 1861*
Archaeoraptor Czerkas vide Sloan, 1999 [nomen nudum]
Archaeornis Petronievics vide Petronievics & Woodward, 1917*
Archaeornithoides Elzanowski & Wellnhofer, 1992
Archaeornithomimus D. A. Russell, 1972
Arctosaurus Adams, 1875*
Argentinosaurus Bonaparte & Coria, 1993
Argyrosaurus Lydekker, 1893
Aristosaurus van Hoepen, 1920
Aristosuchus Seeley, 1887
“Arkanosaurus” Sattler, 1983 [nomen nudum]
Arrhinoceratops Parks, 1925
Arstanosaurus Suslov vide Suslov & Shilin, 1982
Asiaceratops Nessov & Kaznyshkina vide Nessov, Kaznyshkina & Cherepanov, 1989
Asiamericana Nessov, 1995
Asiatosaurus Osborn, 1924
Astrodon Johnston, 1859
Astrodonius Kuhn, 1961
Atlantosaurus Marsh, 1877
Atlasaurus Monbaron, D. A. Russell & Taquet, 1999
Atlascopcosaurus T. Rich & P. Rich, 1989
Aublysodon Leidy, 1868
Augustia Bonaparte, 1998/Zariquiey, 1927
Austrosaurus Longman, 1933
Avaceratops Dodson, 1986
Avalonia Seeley, 1898/Walcott, 1889*
Avalonianus Kuhn, 1961*
Avimimus Kurzanov, 1981
Avipes von Huene, 1932
Avisaurus Brett-Surman & Paul, 1985*
Azendohsaurus Dutuit, 1972