[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Phylum Echinodermata Bruguière, 1789 - echinoderms
     Class Echinoidea (Leske, 1778) - sea urchins and sand dollars
       Order Arbacioida Gregory, 1900
         Family Arbaciidae Gray, 1855
           1 Genus Arbacia Gray, 1835
           2 Genus Arbaciella Mortensen, 1910
           3 Genus Coelopleurus Agassiz, 1838
           4 Genus Habrocidaris Agassiz & Clark, 1907
           5 Genus Podocidaris Agassiz, 1869