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
           Genus †Helaspis Elliott, Dineley & Johnson, 2000, nom. illeg., sedis mutabilis