†order Cyathaspidiformes Kaier 1930
Pteraspidomorpha - Cyathaspidiformes
Parent taxon: Heterostraci according to R. Van Der Laan 2019
See also Elliott 2016, Long 2011 and Nelson et al. 2016
Sister taxa: Amphiaspidiformes, Aporemaspis, Ariaspididae, Cardipeltida, Cardipeltidae, Cardipeltiformes, Ceraspidae, Corvaspidida, Corvaspidiformes, Cyathaspida, Cyathaspididae, Drepanaspidae, Lepidaspidida, Lepidaspidiformes, Olbiaspidida, Palaeaspidi, Protaspidae, Psammolepis, Psammosteiformes, Pteraspidi, Pteraspidiformes, Strosipherus, Tesseraspidida, Tesseraspidiformes, Thelodontidae, Tolypelepidida, Tolypelepidiformes, Traquairaspidida, Traquairaspidiformes