Kingdom Animalia (animals) Eumetazoa (metazoans) Bilateria (bilaterally symmetrical animals) Deuterostomia (deuterostomes) Phylum Chordata (chordates) Craniata (craniates) Subphylum Vertebrata (vertebrates) Class Cephalaspidomorphi (lampreys) Order Petromyzontiformes (lampreys) Family Petromyzontidae (lampreys)