[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 Spatangoida L. Agassiz, 1840
         1 Family Hemiasteridae H.L. Clark, 1917
         2 Family Spatangidae Gray, 1825
         3 Family Schizasteridae Lambert, 1905
         4 Family Brissidae Gray, 1855
         5 Family Loveniidae Lambert, 1905
         6 Family Aeropsidae Lambert, 1896
         7 Family Asterostomatidae Pictet, 1857