Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
   Subclass Neornithes Gadow, 1893 see Clade Neornithes Gadow, 1893
     Infraclass Neoaves Sibley et al., 1988 see Subcohort Neoaves Sibley et al., 1988
       Parvclass Passerae see Superorder Passerimorphae Sibley et al., 1988
         Superorder Passerimorphae Sibley et al., 1988
           Order Passeriformes Linnaeus, 1758
             Suborder Passeri see Suborder Passeres (C. Linnaeus, 1758) C. Linnaeus, 1766
               Parvorder Passerida (C. Linnaeus, 1758) Sibley et al., 1988
                 Superfamily Sylvioidea
                   Family Sylviidae Leach, 1820 - Old World warblers
                     Subfamily Acrocephalinae Salvin, 1882
                       Genus Achaetops Roberts, 1922 see Genus Chaetops Swainson, 1831[1832]
                         Achaetops pycnopygius (Strickland & Sclater, 1852) see Chaetops pycnopygius (P.L. Sclater, 1852)