Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Arthropoda Siebold, 1848 - arthropods
     Subphylum Cheliceriformes
       Class Chelicerata Heymons, 1901
         Subclass Merostomata Dana, 1852 - horseshoe crabs see Class Xiphosura Latreille, 1802
           Order Xiphosura Latreille, 1802 see Class Xiphosura Latreille, 1802
             Family Limulidae Leach, 1819
               Genus Carcinoscorpius Pocock, 1902
               Genus Limulus Müller, 1785
               Genus Tachypleus Leach, 1819