Trilobita - Phacopida - Cheiruridae
Full reference: H. B. Whittington. 1963. Middle Ordovician trilobites from Lower Head, western Newfoundland. Bulletin of the Museum of Comparative Zoology 129(1):1-118
Parent taxon: Cheiruridae according to P. A. Jell and J. M. Adrain 2003
Sister taxa: Acanthoparyphinae, Actinopeltis, Anasobella, Areia, Areiaspis, Borealaspis, Ceraurinella, Ceraurinus, Cerauroides, Cerauromeros, Ceraurus, Cheirurinae, Cheirurus, Chiozoon, Contracheirurus, Crotalocephalina, Crotalocephalus, Cyrtometopella, Cyrtometopus, Deiphon, Didrepanon, Eccoptochile, Gabriceraurus, Hadromeros, Heliomera, Heliomeroides, Hemisphaerocoryphe, Holia, Hyrokybe, Junggarella, Kawina, Ktenoura, Lehua, Nieszkowskia, Onycopyge, Osekaspis, Pandaspinapyga, Paraceraurus, Parayoungia, Parisoceraurus, Pateraspis, Placoparina, Proromma, Protocerauroides, Pseudocheirurus, Pseudosphaerexochus, Radiurus, Remipyga, Skelipyx, Sphaerexochus, Sphaerocoryphe, Sphaexerochinae, Stubblefieldia, Sycophantia, Valongia, Whittakerites, Xystocrania, Youngia
Subtaxa: Cydonocephalus griphus, Cydonocephalus mercurus, Cydonocephalus prolificus, Cydonocephalus prominulus, Cydonocephalus scrobiculus, Cydonocephalus torulus
Type: Cydonocephalus griphus
Ecology: fast-moving low-level epifaunal carnivore