Pteraspidomorpha - Cyathaspida
Full reference: J. Kiaer. 1932. The Downtonian and Devonian vertebrates of Spitsbergen. IV, Suborder Cyathaspida. Skrifter Om Svalbard Og Ishavet 52:1-26
Parent taxon: Heterostraci according to J. Kiaer 1932
See also Loeffler and Dineley 1976
Sister taxa: Amphiaspidiformes, Aporemaspis, Ariaspididae, Aserotaspis, Cardipeltida, Cardipeltidae, Cardipeltiformes, Ceraspidae, Corvaspidida, Corvaspidiformes, Cyathaspidiformes, Drepanaspidae, Guerichosteidae, Lepidaspidida, Lepidaspidiformes, Munchoaspis, Olbiaspidida, Palaeaspidi, Psammolepis, Psammosteiformes, Pteraspidi, Pteraspidiformes, Rimasventeraspis, Strosipherus, Tesseraspidida, Tesseraspidiformes, Tolypelepidida, Tolypelepidiformes, Toombsaspis, Traquairaspidida, Traquairaspidiformes, Gunaspis, Karelosteus, Corveolepis, Homaspidella, Dyreaspis, Archodus, Irregulariaspis, Steinaspis, Clydonaspis, Strophisterus, Ennosviaspis, Kiangsuaspis, Poriferaspis, Obliaspis, Grumantaspis, Yoglinia, Schizosteus, Seretaspis, Allocryptaspis, Pycnaspis, Pilolepsis, Anatolepsis, Listraspis
Subtaxa: Cyathaspidei Poraspidei
Ecology: