Fishes Class Cephalaspidomorphi Kiaer & Stensiö, 1920 see Class Osteostraci Lankester, 1868 Order Petromyzontiformes Berg, 1940 - lampreys Family Petromyzontidae Bonaparte, 1831 - lampreys Subfamily Petromyzontinae Genus Lampreda Rafinesque, 1815, nom. nud.