Lampreys are an ancient extant lineage of jawless fish of the order Petromyzontiformes, placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth. Wikipedia Class: Hyperoartia Phylum: Chordata Order: Petromyzontiformes; Berg, 1940 Scientific name: Petromyzontiformes Kingdom: Animalia Mass: European river lamprey: 82 g, Pacific lamprey: 280 g Encyclopedia of Life