[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Vertebrata (Lamarck, 1801)
         Branch Cephalochorda [monotypic]
           Class Leptocardia Müller
             Genus Amphioxus Yarrell, 1836 see Genus Branchiostoma Costa, 1834