Class †Placodermi McCoy, 1848 Order †Arthrodira Woodward, 1891 see [unranked] Arthrodira Woodward, 1891 †Aspinothoracida see [unranked] Aspinothoracidi Stensiö, 1959 Family †mylostomatids? Woodward, 1891 Family †Titanichthyidae Dean, 1901 Genus †Titanichthys Newberry, 1885 †Titanichthys agassiziᵀ Newberry, 1885