• "Lower Heterobranchia"
• [unassigned] Caenogastropoda (temporary name)
• [unassigned] Cladobranchia (temporary name)
• [unassigned] Euheterodonta (temporary name)
• [unassigned] Helicina (temporary name)
• [unassigned] Heterobranchia (temporary name)
• [unassigned] Neogastropoda (temporary name)
• [unassigned] Stylommatophora (temporary name)
• [unassigned] Pectinidae (temporary name)
• “Montereina” sensu Dayrat, 2010 (unaccepted > unavailable name)
• “Montereina” concinna (Alder & Hancock, 1864) represented as Discodoris concinna (Alder & Hancock, 1864)
• Ablennes Jordan & Fordice, 1887
• Ablennes hians (Valenciennes, 1846)
• Abudefduf Forsskål, 1775
• Abudefduf hoefleri (Steindachner, 1881)
• Abudefduf saxatilis (Linnaeus, 1758)
• Abudefduf sexfasciatus (Lacepède, 1801)
• Abudefduf vaigiensis (Quoy & Gaimard, 1825)
• Abyla Quoy & Gaimard, 1827
• Abyla trigona Quoy & Gaimard, 1827
• Abylidae L. Agassiz, 1862
• Abylinae L. Agassiz, 1862
• Acabaria Gray, 1859 accepted as Melithaea Milne Edwards, 1857
• Acabaria erythraea (Ehrenberg, 1834) accepted as Melithaea erythraea (Ehrenberg, 1834)
• Acalyptrata
• Acantharctus Holthuis, 2002
• Acantharctus posteli (Forest, 1963)
• Acanthaster Gervais, 1841
• Acanthaster planci (Linnaeus, 1758)
• Acanthasteridae
• Acanthochitona Gray, 1821
• Acanthochitona achates (A. Gould, 1859)
• Acanthochitona rubrolineata (Lischke, 1873)
• Acanthochitonidae Pilsbry, 1893
• Acanthochitonina
• Acanthochitoninae Pilsbry, 1893
• Acanthochromis Gill, 1863
• Acanthochromis polyacanthus (Bleeker, 1855)
• Acanthocolpidae Lühe, 1906
• Acanthodesia Canu & Bassler, 1919 accepted as Biflustra d'Orbigny, 1852
• Acanthodesia savartii (Audouin, 1826) accepted as Biflustra savartii (Audouin, 1826)
• Acanthogobius Gill, 1859
• Acanthogobius flavimanus (Temminck & Schlegel, 1845)
• Acantholobulus Felder & Martin, 2003
• Acantholobulus pacificus (Edmondson, 1931)
• Acanthopagrus Peters, 1855
• Acanthopagrus bifasciatus (Forsskål, 1775)
• Acanthophora J.V.Lamouroux, 1813
• Acanthophora muscoides (Linnaeus) Bory de Saint-Vincent, 1828
• Acanthophora nayadiformis (Delile) Papenfuss, 1968
• Acanthophora spicifera (M.Vahl) Børgesen, 1910
• Acanthopleura Guilding, 1830
• Acanthopleura gemmata (Blainville, 1825)
• Acanthopleurinae Dall, 1889
• Acanthostega
• Acanthostegomorpha
• Acanthostracion Bleeker, 1865
• Acanthostracion polygonium Poey, 1876
• Acanthostracion polygonius Poey, 1876 accepted as Acanthostracion polygonium Poey, 1876
• Acanthuridae Bonaparte, 1835
• Acanthuriformes
• Acanthurinae
• Acanthuroidei accepted as Acanthuriformes
• Acanthurus Forsskål, 1775
• Acanthurus achilles Shaw, 1803
• Acanthurus chirurgus (Bloch, 1787)
• Acanthurus coeruleus Bloch & Schneider, 1801
• Acanthurus gahhm (Forsskål, 1775)
• Acanthurus guttatus Forster, 1801
• Acanthurus monroviae Steindachner, 1876
• Acanthurus pyroferus Kittlitz, 1834
• Acanthurus sohal (Forsskål, 1775)
• Acar Gray, 1857
• Acar plicata (Dillwyn, 1817)
• Acari
• Acaridae
• Acariformes
• Acartia Dana, 1846
• Acartia (Acanthacartia) Steuer, 1915
• Acartia (Acanthacartia) tonsa Dana, 1849
• Acartia (Acartiura) Steuer, 1915
• Acartia (Acartiura) omorii Bradford, 1976
• Acartia (Odontacartia) Steuer, 1915
• Acartia (Odontacartia) centrura Giesbrecht, 1889
• Acartia centrura Giesbrecht, 1889 represented as Acartia (Odontacartia) centrura Giesbrecht, 1889
• Acartia grani Sars G.O., 1904 accepted as Paracartia grani Sars G.O., 1904 represented as Paracartia grani grani Sars G.O., 1904
• Acartia hasanii Unal, Shmeleva & Kideys, 2002 (unaccepted > nomen nudum)
• Acartia ioannae Unal, Shmeleva & Kideys, 2002 (uncertain > nomen dubium)
• Acartia jannetei Shmeleva & Selifonova, 2005 (unaccepted > nomen nudum)
• Acartia tonsa Dana, 1849 represented as Acartia (Acanthacartia) tonsa Dana, 1849
• Acartiella Sewell, 1914
• Acartiella sinensis Shen & Lee, 1963
• Acartiidae Sars G.O., 1903
• Acarus Linnaeus, 1758
• Acarus siro Linnaeus, 1758
• Acentrogobius Bleeker, 1874
• Acentrogobius pflaumii (Bleeker, 1853)
• Acerotisa Strand, 1928
• Acervulina Schultze, 1854
• Acervulina inhaerens Schultze, 1854