Parent taxon: Blastozoa according to S. L. Sheffield and C. D. Sumrall 2019
See also Beaver et al. 1967, Bockelie 1984 and Paul and Bockelie 1983
Sister taxa: Asteroblastida, Blastoidea, Crinoidea, Diploporita, Eocrinoidea, Glyptosphaeritida, Lepidocystoidea, Parablastoidea, Paracrinoidea, Rhombifera, Rhombifera, Soluta
Subtaxa: Aristocystitidae Holocystitidae Sphaeronitidae
Type: Sphaeronitidae
Ecology: stationary epifaunal suspension feeder
Distribution:
• Devonian of Czechia (8 collections)
• Niagaran of United States (1: Ohio)
• Silurian to Devonian of United States (1: Oklahoma)
• Silurian of Australia (2), China (1), United States (24: Arkansas, Illinois, Indiana, New York, Tennessee, Wisconsin)
• Dobrotivian of Czechia (2), France (1), Morocco (1), Spain (10)
• Liben of Czechia (1)
• Arenig of China (1)
• Ordovician of Algeria (1), Belarus (1), Belgium (5), Canada (2: Quebec), China (9), Czechia (22), Estonia (3), Iran (2), Morocco (8), Norway (26), Portugal (1), Spain (8), Sweden (45), Thailand (1), the United Kingdom (8)
Total: 195 collections including 269 occurrences