Chelicerata Heymons, 1901
   Scorpiones Koch, 1837 - scorpions
     †Holosternina Kjellesvig-Waering, 1986
       1 Superfamily †Acanthoscorpionoidea Kjellesvig-Waering, 1986
       2 Superfamily †Allopalaeophonoidea Kjellesvig-Waering, 1986 [monotypic]
       3 Superfamily †Eoctonoidea Kjellesvig-Waering, 1986
       4 Superfamily †Gigantoscorpionoidea Kjellesvig-Waering, 1986 [monotypic]
       5 Superfamily †Mesophonoidea Wills, 1910
       6 Superfamily †Palaeoscorpoidea Dunlop, Penney & Jekel, 2010, orth. inval. [monotypic] see Superfamily Palaeoscorpioidea Lehmann, 1944
       7 Superfamily †Spongiophonoidea Kjellesvig-Waering, 1986