[Phylum] Chordata Bateson, 1885 - chordates Subphylum Craniata auct. Infraphylum Vertebrata Lamarck, 1801 - vertebrates Superclass †Osteostracomorphi Class †Osteostraci Lankester, 1868 Order †Thyestiformes Family †Procephalaspididae Stensiö, 1958 Genus †Procephalaspis Denison, 1951