vertebrates Lamarck, 1801 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
   †Pteraspidimorphi [paraphyletic]
     †Heterostraci Lankester, 1868, sedis mutabilis - heterostracans
       Family †Cyathaspididae Kiaer, 1932, nom. praeval. [paraphyletic]
         Order †Pteraspidiformes Berg, 1940
           [Suborder] †Psammosteida Kiaer, 1932 see Suborder Psammosteoidei Kiaer, 1932
             1 Genus †Psammosteus Agassiz, 1844, sedis mutabilis
             2 Genus †Psammolepis Agassiz, 1844, sedis mutabilis
             3.1 Genus †Drepanaspis Schlüter, 1887
             3.2.1 [Genus] †Perschia Randle, 2017, nom. ined., orth. inval. see Genus Perscheia Elliott, Mark-Kurik & Daeschler, 2004
             3.2.2 Genus †Obruchevia Whitley, 1940