[Phylum] Chordata Bateson, 1885 - chordates
   Subphylum Craniata auct.
     Infraphylum Vertebrata Lamarck, 1801 - vertebrates
       Superclass †Pteraspidomorphi Goodrich, 1909 [monotypic]
         Class †Pteraspidomorpha
           Subclass †Heterostraci Lankester, 1868
             Order †Pteraspidiformes Berg, 1940
               Suborder †Psammosteoidei Kiaer, 1932
                 Family †Obrucheviidae Tarlo, 1965, "nom. praeval."
                   Genus †Aspidosteus Obruchev, 1941, nom. illeg. see Genus Obruchevia Whitley, 1940