Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Craniata Linnaeus, 1758 see Subphylum Vertebrata Cuvier, 1812
     Pisces
       Class Actinopterygii Woodward, 1891 - ray-finned fishes
         Order Notacanthiformes Goodrich, 1909 - spiny eels
           1 Family Halosauridae Günther, 1868 - halosaurs
           2 Family Notacanthidae Rafinesque, 1815 - spiny eels