Chelicerata Heymons, 1901
   Scorpiones Koch, 1837 - scorpions
     [plesion] Family †Proscorpiidae Scudder, 1885
       1 Genus †Archaeoctonus Pocock, 1911
       2 Genus †Hydroscorpius Kjellesvig-Waering, 1986
       3 Genus †Labriscorpio Leary, 1980
       4 Genus †Proscorpius Whitfield, 1885
       5 Genus †Pseudoarchaeoctonus Kjellesvig-Waering, 1986
       6 Genus †Waeringoscorpio Størmer, 1970