Superfamily Dalmanitoidea
Cephalon: typically bearing genal spines, generally with well-developed preglabellar field, median region of glabella bearing muscle scars; eyes tend to mesial or posterior, true vincular furrows lacking.
Thorax: variable, but often with spinose tips.
Pygidium: typically subisopygous, often spinose (terminal or marginal spines); axial rings of consistent depth along length of pygidial axis, axial furrows with simple and consistent convergence angle.
Families: Dalmanitidae, Diaphanometopidae, Prosopiscidae
Genera: Dalmanites, Diaphanometopus, Huntoniatonia, Odontocephalus, Odontochile, Prosopiscus

Superfamily Acastoidea
Cephalon: axial furrows slightly to moderately divergent, anterior glabellar lobes and furrows usually not fused (although furrows may be indistinct), eyes typically distant from posterior border furrows, but not strongly anterior; frontal glabellar lobe auxilliary impression system triangular in outline, maximum width of glabella adjacent to preglabellar furrow, median region of glabella devoid of muscle scars; cephalic margin "shouldered," laterally convex course of genal margin topographically distinct from curvature of axial margin
Thorax: pleural endings blunt, rounded, or angular, sometimes spinose.
Pygidium: micropygous to subisopygous, sometimes spinose (expressed as marginal spines), pygidial axis with deep, apodemal anterior ring furrows, with abrupt transition to shallow posterior ring furrows; coincident decrease in angle of axial furrow convergence.
Other: often similar in general body form to Phacopoidea via convergent evolution, but glabellar and other differences as noted above.
Families: Acastidae, Calmoniidae.
Genera: Acaste, Acastoides, Asteropyge, Comura, Calmonia, Greenops, Metacanthina, Metacryphaeus, Pennaia, Phacopina, Psychopyge, Treveropyge