Vertebrata Cuvier, 1812 - vertebrates Gnathostomata Class †Placodermi McCoy, 1848 Order †Acanthothoraci Stensiö, 1944 see Order Acanthothoraciformes 1 Family †Palaeacanthaspidae Stensiö, 1944 2 Family †Weejasperaspididae White, 1978