Phylum Arthropoda
Subphylum Chelicerata
Class Trilobita
Order Ptychopariida 

    Suborder Ptychopariina
          Superfamily Ellipsocephaloidea
                Family Agraulidae
                Family Bigotinidae
                Family Chengkouiidae
                Family Ellipsocephalidae
                Family Estaingiidae
                Family Palaeolenidae
                Family Yunnanocephalidae 
          Superfamily Ptychparioidea
                Family Alokistocaridae
                Family Antagmidae
                Family Asaphiscidae
                Family Atopidae
                Family Bolaspididae
                Family Cedariidae
                Family Changshaniidae
                Family Conocoryphidae
                Family Crepicephalidae
                Family Diceratocephalidae
                Family Elviniidae
                Family Eulomidae
                Family Ignotogregatidae
                Family Inouyiidae
                Family Isocolidae
                Family Kingstoniidae
                Family Lisaniidae
                Family Llanoaspididae
                Family Lonchocephalidae
                Family Lorenzellidae
                Family Mapaniidae
                Family Marjumiidae
                Family Menomoniidae
                Family Nepeidae
                Family Norwoodiidae
                Family Papyriaspididae
                Family Phylacteridae
                Family Proasaphiscidae
                Family Ptychopariidae
                Family Shumardiidae
                Family Solenopleuridae
                Family Tricrepicephalidae
                Family Utiidae
                Family Wuaniidae 
    Suborder Olenina
          Superfamily [[]]
                Family Olenidae
                Family Prosopiscidae
                Family Diaphanometopidae 
    Suborder: Incertae sedis
          Superfamily Incertae sedis
                Family Avoninidae
                Family Catillicephalidae
                Family Ityophoridae
                Family Plethopeltidae