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
               Clade discaria Cavalier-Smith, 2021
                 Clade dorsates Cavalier-Smith, 2021
                   Clade podiates Cavalier-Smith, 2012
                     [crown] Clade Amorphea Adl et al. 2012 [Simpson, Medina & Adl 2020]
                       [crown] Clade Obazoa Brown, Sharpe, Silberman, Heiss, Lang, Simpson & Roger 2013
                         [crown] Clade Opisthokonta Cavalier-Smith 1987 [Simpson & Medina 2020] - animal-fungal clade
                           Superkingdom Holozoa Lang, O'Kelly, Nerad, Gray & Burger, 2002
                             Clade filozoa Shalchian-Tabrizi, Minge, Espelund, Orr, Ruden, Jakobsen & Cavalier-Smith, 2008
                               Kingdom Animalia Linnaeus, 1758 - animals
                                 Clade Planulozoa Wallberg, Thollesson, Farris & Jondelius 2004
                                   Subkingdom Bilateria Hatschek, 1888 - bilaterians
                                     Clade Nephrozoa Jondelius, Ruiz-Trillo, Baguñà & Riutort 2002
                                       Infrakingdom Deuterostomia Grobben, 1908
                                         Phylum Chordata Bateson, 1885 - chordates
                                           Subphylum Vertebrata Cuvier, 1812 - vertebrates
                                             [stem] Superclass †Pteraspidomorphi Goodrich, 1909 [monotypic]
                                               Class †Pteraspidomorphi Goodrich, 1909
                                                 Subclass †Heterostraci Lankester, 1868
                                                   Order †Pteraspidiformes Berg, 1940
                                                     Genus †Pteropsis Conrad, 1860
                                                     1 Family †Anchipteraspididae Elliott, 1984
                                                     2 Family †Protaspididae Randle & Sansom, 2017
                                                     3 Family †Protopteraspididae Novitskaya, 1983
                                                     4 Family †Psammosteidae Traquair, 1896
                                                     5 Family †Pteraspididaeᵀ Claypole, 1885