Mikko's Phylogeny Archive Main Groups of Protostomes   Ptychopariida

After Gon III, 2002

<==o †PTYCHOPARIIDA Swinnerton, 1915
   |?- †Ithyophoridae [Ityophoridae, lapsus calami]
   |-- †Ptychopariina Richter, 1932
   `--o Olenina [Olenoidea, Olenacea]
      `-- †Olenidae

Reference(s):

Gon III, S. M., 2002: Systematic listing of Trilobite families.
–iNet: http://www.aloha.net/~smgon/trisystem.htm