Chordata Bateson, 1885 - chordates Class †Arthrodira Woodward, 1891 - arthrodires see Order Arthrodiriformes Grande & Eastman, 1986 Order †Arthrothoraci see Order Arthrodiriformes Grande & Eastman, 1986 Family †Mylostomidae Dean, 1901, nom. illeg. see Family Mylostomatidae Woodward, 1891