Vertebrata Cuvier, 1812 - vertebrates Class Agnatha Cope, 1889 [paraphyletic] Subclass †Pteraspidomorphi Goodrich, 1909 see Class Pteraspidomorphi Goodrich, 1909 Order †Heterostraci Lankester, 1868 - heterostracans see Subclass Heterostraci Lankester, 1868 Family †Cyathaspididae Flower & Wayland-Smith, 1952 Genus †Asketaspis Dineley & Loeffler, 1976