[Phylum] Chordata Bateson, 1885 - chordates Subphylum Craniata auct. Infraphylum Vertebrata Lamarck, 1801 - vertebrates Superclass Gnathostomata Gegenbaur, 1874 - jawed vertebrates Class †Placodermi McCoy, 1848 Order †Acanthothoraci Stensiö, 1944 Family †Palaeacanthaspidae Stensiö, 1944 Genus †Palaeacanthaspis Brotzen, 1934