Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Biota
           "neomura"
             Domain Eukaryota Chatton, 1925 - eukaryotes
               "protists" incertae sedis
                 Group †Calcitarcha G.J.M. Versteegh, T. Servais, Streng, Munnecke & Vachard (2009), incertae sedis [polyphyletic] - calcispheres
                   Genus †Asterosphaerella Villain (1975)