Subclass †Heterostraci Lankester, 1868
   Family †Cyathaspididae Kiaer, 1932, nom. praeval.
     Subfamily †Tolypelepidinae Strand, 1934 (1932), nom. praeval. [paraphyletic]
       Genus †Asketaspis Dineley & Loeffler, 1976
         1 †Asketaspis interstincta