[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Echinoderma
         Branch Ambulacrata
           Class Echinoidea (Leske, 1778) - sea urchins and sand dollars
             Grade Autechini
               Branch Petalosticha
                 Order Spatangidæ Gray, 1825
                   1 Genus Ananchytes Lamarck, 1816 see Genus Ananchites Lamarck, 1801
                   2 Genus Pourtalesia Agassiz, 1869