Phylum Chordata Bateson, 1885 - chordates Subphylum Vertebrata Cuvier, 1812 - vertebrates Class Cephalaspidomorpha see Class Cephalaspidomorphi Moy-Thomas & Mile, 1971 Order Petromyzontiformes Berg, 1940 - lampreys Family Petromyzontidae Bonaparte, 1832 - lampreys Genus Lampetra Bonnaterre, 1788 Genus Lethenteron Creaser & Hubbs, 1922 Genus Petromyzon Linnaeus, 1758