Chelicerata Heymons, 1901
Count: 2c;12o; †6o;2f;23g
   Xiphosura s. lat. Latreille, 1802 - horseshoe crabs see Class Xiphosura Latreille, 1802
  Count: 1c; †2f;13g
     Prosomapoda Lamsdell, 2013
    Count: 1c; †2f;13g
       Genus †Venustulus Moore, 2005
      Count: -