[Phylum] Chordata Bateson, 1885 - chordates Subphylum Craniata auct. Infraphylum Vertebrata Lamarck, 1801 - vertebrates Superclass †Osteostracomorphi Class †Osteostraci Lankester, 1868 Order †Cephalaspidiformes Halstead Tarlo, 1967 Suborder †Scolenaspidoidei Afanassieva, 1991 Family †Zenaspididae Stensiö, 1958 1 Genus †Zenaspis Lankester, 1870