Alternative spelling: Dikelocephalacea
Parent taxon: Asaphida according to Bell 2012
See also Hughes 1994
Sister taxa: Aethodionide, Anomocarellidae, Anomocaridae, Anomocaroidea, Asaphina, Asaphoidea, Cyclopygoidea, Eurekiidae, Hungaiidae, Ordosiidae, Parabumasttides, Pseudocyclopyge, Pterocephalidae, Remopleuridae, Rhyssometopidae, Trinucleoidea
Subtaxa: Dikelocephalidae Dikelocephaliidae Ptychaspididae
Distribution:
• Ordovician of Antarctica (1 collection), Australia (1), Canada (3: Newfoundland and Labrador, Yukon), China (1), Mexico (3), the Russian Federation (3), the United Kingdom (1)
• Skullrockian of Canada (3: Alberta, British Columbia), United States (3: Texas)
• Taoyuanian of China (9), Türkiye (1)
• Cambrian of Australia (27), Canada (53: Alberta, Newfoundland, Newfoundland and Labrador, Quebec, Yukon), China (32), Iran (4), Kazakhstan (15), South Korea (6), Türkiye (1), United States (180: Alaska, Colorado, Idaho, Minnesota, Missouri, Montana, Nevada, New Mexico, New York, Oklahoma, Pennsylvania, South Dakota, Texas, Utah, Vermont, Virginia, Wisconsin, Wyoming)
Total: 347 collections including 691 occurrences