Here are a few representative Ptychopariina:
Compare the pictorial format above with the descriptive narrative below:
Introduction: An extremely large, heterogenous order, classification problematic, with specialized offshoots that are hard to frame within a general diagnosis.
Cephalon: typically with opisthoparian facial sutures, with gently forward-tapering simple glabella bearing a broad, rounded front (e.g., Olenina, Ptychopariina), but some with pronounced cephalic fringes (e.g., Harpina), usually with 3 pairs of rather narrow parallel glabellar furrows; natant hypostome.
Thorax: typically large with 8+ thoracic segments.
Pygidium: quite variable, but typically with a small pygidium bearing a border (Cambrian) or a larger pygidium with or without border (post-Cambrian).
Occurrence: Lower Cambrian to Upper Ordovician.
Suborders: Ptychopariina, Olenina.
PTYCHOPARIIDA includes two Suborders: