[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Phylum Cnidaria Hatschek, 1888 - cnidarians
     Anthozoa Ehrenberg, 1831
       Hexacorallia Haeckel, 1866 - sea anemones and true corals see Subclass Zoantharia de Blainville, 1830
         Order Ceriantharia
           Family Arachnacthidae see Family Arachnactidae McMurrich, 1910
             1 Genus Arachnanthus Carlgren, 1912
             2 Genus Isarachnanthus Carlgren, 1924
             3 Genus Arachnactis Sars, 1846