Abra aequalis (Say, 1822) (extant flag source)
Acanthaster planci (Linnaeus, 1758) (extant flag source)
Acanthochitona pygmaea (Pilsbry, 1893) (extant flag source)
Accipiter gentilis (Linnaeus, 1758) (extant flag source)
Accipiter nisus (Linnaeus, 1758) (extant flag source)
Acesta excavata (Fabricius, 1779) accepted as Lima excavata (Fabricius, 1779) (extant flag source)
Acharax johnsoni (Dall, 1891) (extant flag source)
Acila castrensis (Hinds, 1843) (extant flag source)
Acipenser brevirostrum Lesueur, 1818 (extant flag source)
Acipenser fulvescens Rafinesque, 1817 (extant flag source)
Acipenser oxyrhynchus Mitchill, 1814 accepted as Acipenser oxyrinchus Mitchill, 1815 (extant flag source)
Acmaea digitalis (Rathke, 1833) accepted as Collisella digitalis (Rathke, 1833) (extant flag source)
Acmaea mitra Eschscholtz, 1833 (extant flag source)
Acmaea pelta Rathke, 1833 accepted as Collisella pelta (Rathke, 1833) (extant flag source)
Acmaea scutum Rathke, 1833 accepted as Notoacmea scutum (Rathke, 1833) (extant flag source)
Acropora austera (Dana, 1846) (extant flag source)
Acropora brueggemanni (Brook, 1893) (extant flag source)
Acropora digitifera (Dana, 1846) (extant flag source)
Acropora formosa (Dana, 1846) (extant flag source)
Acropora gemmifera (Brook, 1892) (extant flag source)
Acropora horrida (Dana, 1846) (extant flag source)
Acropora humilis (Dana, 1846) (extant flag source)
Acropora monticulosa (Brüggemann, 1879) (extant flag source)
Acropora palmata (Lamarck, 1816) (extant flag source)
Acropora samoensis (Brook, 1891) (extant flag source)
Acropora yongei Veron & Wallace, 1984 (extant flag source)
Acteocina bidentata (d'Orbigny, 1841) (extant flag source)
Acteocina canaliculata (Say, 1826) (extant flag source)
Acteocina candei (d'Orbigny, 1841) (extant flag source)
Acteocina lepta Woodring, 1928 (extant flag source)
Aelurosaurus felinus Boulenger, 1885 accepted as Aeluroscalabotes felinus Günther, 1864 (extant flag source)
Aequipecten gibbus (Linnaeus, 1758) accepted as Argopecten gibbus (Linnaeus, 1758) (extant flag source)
Aequipecten irradians (Lamarck, 1819) accepted as Argopecten irradians (Lamarck, 1819) (extant flag source)
Aequipecten muscosus (W. Wood, 1828) (extant flag source)
Aequipecten opercularis (Linnaeus, 1758) (extant flag source)
Ailuropoda melanoleuca (David, 1869) (extant flag source)
Alca torda Linnaeus, 1758 (extant flag source)
Alces alces (Linnaeus, 1758) (extant flag source)
Alle alle (Linnaeus, 1758) (extant flag source)
Alopecias superciliosus Lowe, 1841 accepted as Alopias superciliosus Lowe, 1841 (extant flag source)
Alopex lagopus (Linnaeus, 1758) accepted as Vulpes lagopus (Linnaeus, 1758) (extant flag source)
Alopias superciliosus Lowe, 1841 (extant flag source)
Alopias vulpinus (Bonnaterre, 1788) (extant flag source)
Alosa sapidissima (Wilson, 1811) (extant flag source)
Amauropsis islandica (Gmelin, 1791) (extant flag source)
Americardia media (Linnaeus, 1758) (extant flag source)
Amiantis callosa (Conrad, 1837) (extant flag source)
Ammospermophilus leucurus (Merriam, 1889) (extant flag source)
Amphissa versicolor Dall, 1871 (extant flag source)
Anachis obesa (C.B. Adams, 1845) (extant flag source)
Anadara baughmani Hertlein, 1951 (extant flag source)
Anadara brasiliana (Lamarck, 1819) (extant flag source)
Anadara lienosa (Say, 1832) (extant flag source)
Anadara notabilis (Röding, 1798) (extant flag source)
Anadara ovalis (Bruguière, 1789) (extant flag source)
Anadara secticostata (Reeve, 1844) (extant flag source)
Anadara springeri Rehder & Abbott, 1951 accepted as Anadara baughmani Hertlein, 1951 (extant flag source)
Anadara transversa (Say, 1822) (extant flag source)
Anas acuta Linnaeus, 1758 (extant flag source)
Anas americana Gmelin, 1789 (extant flag source)
Anas clypeata Linnaeus, 1758 (extant flag source)
Anas discors Linnaeus, 1766 (extant flag source)
Anas platyrhynchos Linnaeus, 1758 (extant flag source)
Anatina anatina (Spengler, 1802) (extant flag source)
Andromeda polifolia Linnaeus (extant flag source)
Anodontia alba Link, 1807 (extant flag source)
Anolis carolinensis Voigt, 1832 (extant flag source)
Anomalocardia brasiliana (Gmelin, 1791) (extant flag source)
Anomalocardia cuneimeris (Conrad, 1846) accepted as Anomalocardia auberiana (d'Orbigny, 1853) (extant flag source)
Anomia aculeata Müller, 1776 accepted as Anomia squamula Linnaeus, 1758 (extant flag source)
Anomia ephippium Linnaeus, 1758 (extant flag source)
Anomia peruviana d'Orbigny, 1846 (extant flag source)
Anomia simplex d'Orbigny, 1853 (extant flag source)
Antillophos candeanus (d'Orbigny, 1842) (extant flag source)
Antillophos candei (d'Orbigny, 1848) accepted as Antillophos candeanus (d'Orbigny, 1842) (extant flag source)
Antilocapra americana (Ord, 1815) (extant flag source)
Antilope americana Ord, 1815 accepted as Antilocapra americana (Ord, 1815) (extant flag source)
Antrozous pallidus (LeConte, 1856) (extant flag source)
Aplodinotus grunniens Rafinesque, 1819 (extant flag source)
Aplodontia rufa (Rafinesque, 1817) (extant flag source)
Apolymetis intastriata (Say, 1827) accepted as Psammotreta intastriata (Say, 1826) (extant flag source)
Aporrhais occidentalis (Beck, 1836) (extant flag source)
Aquila chrysaetos (Linnaeus, 1758) (extant flag source)
Arca campechiensis Gmelin, 1791 accepted as Anadara ovalis (Bruguière, 1789) (extant flag source)
Arca imbricata Bruguière, 1789 (extant flag source)
Arca occidentalis Philippi, 1847 accepted as Arca zebra (Swainson, 1833) (extant flag source)
Arca reticulata Gmelin, 1791 (extant flag source)
Arca umbonata Lamarck, 1819 accepted as Arca imbricata Bruguière, 1789 (extant flag source)
Arca zebra (Swainson, 1833) (extant flag source)
Archaeolacerta bedriagae Lanza et al., 1984 accepted as Lacerta bedriagae Camerano, 1885 (extant flag source)
Architectonica granulata (Lamarck, 1816) accepted as Architectonica nobilis Röding, 1798 (extant flag source)
Architectonica nobilis Röding, 1798 (extant flag source)
Architectonica perspectiva (Linnaeus, 1758) (extant flag source)
Archosargus probatocephalus (Walbaum, 1792) (extant flag source)
Arcinella arcinella (Linnaeus, 1767) (extant flag source)
Arcinella cornuta Conrad, 1866 (extant flag source)
Arcopsis adamsi (Dall, 1886) (extant flag source)
Arctica islandica (Linnaeus, 1767) (extant flag source)
Arctocephalus australis (Zimmermann, 1783) (extant flag source)
Arctocephalus forsteri (Lesson, 1828) (extant flag source)