Chordata Bateson, 1885 - chordates Class †Arthrodira Woodward, 1891 - arthrodires see Order Arthrodiriformes Grande & Eastman, 1986 Order †Stegophthalami see Class Placodermi McCoy, 1848 Family †Asterosteidae Woodward, 1891 [monotypic] Genus †Asterosteus Newberry, 1875