Trilobita - Phacopida - Cheiruridae
Full reference: R. Ludvigsen. 1976. New cheirurinid trilobites from the lower Whittaker Formation (Ordovician), southern Mackenzie Mountains. Canadian Journal of Earth Sciences 13(7):947-959
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, Cydonocephalus, 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, Xystocrania, Youngia
Subtaxa: Whittakerites planatus
Ecology: fast-moving low-level epifaunal carnivore