Ptychoparella_cordilleraeEoptychoparia_piochensisPianaspis_sorsPapyriaspis_lanceolaAmecephalus_idahoenseAmecephalus_piochensisAmecephalus_cleoraAmecephalus_laticaudumAltiocculus_americanusAltiocculus_harrisiAltiocculus_drumensisAltiocculus_concavusProehmaniella_basilicaEhmaniella_waptaensisEhmaniella_fronsplanataElrathiella_euthyopsisAlokistocare_paranotatumAlokistocare_swasiiAlokistocare_subcoronatumOsteologyMaximum ParsimonyBased on reanalysis of the original matrix.Sundberg_1999abSundberg_1999aa