[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Appendiculata {Lankester}
         Branch Gnathopoda Straus-Durkheim, 1829
           Grade Condylopoda
             Class Arachnida Lamarck, 1801
               Branch Tracheopulmonata
                 Order Scorpionidea
                   Genus Scorpio Linnaeus, 1758