Chelicerata Heymons, 1901
   Scorpiones Koch, 1837 - scorpions
     †Meristosternina Kjellesvig-Waering, 1986
       1 Superfamily †Cyclophthalmoidea Thorell & Lindström, 1885
       2 Superfamily †Palaeobuthoidea Kjellesvig-Waering, 1986 [monotypic]