Subclass †Heterostraci Lankester, 1868
   Family †Cyathaspididae Kiaer, 1932, nom. praeval.
     Subfamily †Tolypelepidinae Strand, 1934 (1932), nom. praeval. [paraphyletic]
       1 Genus †Asketaspis Dineley & Loeffler, 1976
       2.1 Genus †Tolypelepis Pander, 1856, sedis mutabilis
       2.2-n Genus †Ptomaspis Denison, 1963, sedis mutabilis [sister group to excluded taxa]