Class †Placodermi McCoy, 1848 Order †Arthrodira Woodward, 1891 see Order Arthrodiriformes Grande & Eastman, 1986 Suborder †Brachythoraci Gross, 1932 Family †Homostiidae Jaekel 1 ?Genus †Atlantidosteus H. Lelièvre, 1984 2 Genus †Homostius Asmuss, 1856