Subclass †Heterostraci Lankester, 1868
   Family †Cyathaspididae Kiaer, 1932, nom. praeval.
     Subfamily †Cyathaspidinae [paraphyletic]
       Genus †Archegonaspis Jaekel, 1927 [sister group to excluded taxa]
         1 †Archegonaspis integra
         2 †Archegonaspis lindstromi