Chelicerata Heymons, 1901
   Pseudoscorpiones De Geer, 1778
     Heterosyphronida Dunlop, Penney & Jekel, 2020, orth. inval. see Suborder Heterosphyronida Chamberlin, 1929
       Superfamily Chthonoidea Dunlop, Penney & Jekel, 2010, orth. inval. see Superfamily Chthonioidea Daday, 1888
         Family Chthoniidae Daday, 1888
           1 Genus †Chelignathus Menge, 1854
           2 Genus Chthonius Koch, 1843
           3 Genus Lechytia Balzan, 1892
           4 Genus Paraliochthonius Beier, 1956
           5 Genus Pseudochthonius Balzan, 1892
           6 Genus Tyrannchthonius Dunlop, Penney & Jekel, 2011, orth. inval. see Genus Tyrannochthonius Chamberlin, 1929
           7 Genus †Weygoldtiella Harvey, Cosgrove, Harms, Selden, Shih & Wang, 2018