Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Clade neomura Cavalier-Smith, 1987
             Domain Eukaryota Chatton, 1925 - eukaryotes
               "protists" incertae sedis
                 Group †Acritarcha Evitt, 1963, incertae sedis [polyphyletic] - acritarchs
                   Genus †Ammonidium Lister, 1970
                     †Ammonidium ludloviense Lister, 1970 ex Dorning, 1981 emend.
                     †Ammonidium microcladumᵀ (Downie, 1963)
                     †Ammonidium waldronense (Tappan & Loeblich, 1971) Dorning, 1981a