|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||Age range and collections|
Trilobita - Phacopida - Acastidae
If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
|G. D. Edgecombe 1993||Auxilliary impression system including scars on median region of frontal glabellar lobe; genal angle with slender spine; pygidium large, faintly pointed posteromedially, with eight defined pleural furrows, 12 axial rings, posterior ring furrows curved backward medially; border strongly defined [plesiomorphies: LI long (exsag.); Sl inclined abaxially, with proximal bifurcation]|