Parent taxon: Asaphida according to R. A. Fortey and D. L. Bruton 2013
See also Adrain 2011
Sister taxa: Aethodionide, Anomocarellidae, Anomocaridae, Anomocaroidea, Asaphina, Asaphoidea, Dikelocephaloidea, Eurekiidae, Hungaiidae, Ordosiidae, Parabumasttides, Pseudocyclopyge, Remopleuridae, Rhyssometopidae, Trinucleoidea
Subtaxa: Cyclopygidae Nileidae Symphysurinidae Taihungshaniidae
Type: Cyclopygidae
Ecology: fast-moving low-level epifaunal carnivore
Distribution:
• Dobrotivian of the Czech Republic (3 collections), France (1), Morocco (1), Portugal (1), Spain (3)
• Uhaku of Sweden (5)
• Letna of the Czech Republic (1)
• Liben of the Czech Republic (1)
• Chazyan of Canada (4: Newfoundland and Labrador)
• Whiterockian of Canada (24: Newfoundland, Newfoundland and Labrador), Norway (4), United States (29: Nevada, Oklahoma, Utah)
• Fennian of France (1), United States (1: Nevada)
• Volkhov of Estonia (1), the Russian Federation (14), Sweden (19)
• Langevoja of Sweden (7)
• Hunderum of Sweden (6)
• Dawan of China (4)
• Klabava of the Czech Republic (2), France (1)
• Arenigian of Canada (2: Northwest Territories), China (21)
• Arenig of Argentina (3), Bolivia (1), China (65), France (5), Iran (1), Morocco (1), Norway (4), the Russian Federation (1), Spain (1), Sweden (5), the United Kingdom (5)
• Ordovician of Argentina (7), Australia (2), Canada (43: Alberta, British Columbia, Newfoundland, Newfoundland and Labrador, Northwest Territories, Quebec, Yukon), China (115), the Czech Republic (14), France (4), Greenland (4), Iran (6), Ireland (10), Italy (3), Kazakhstan (5), Morocco (2), Norway (16), Oman (1), the Russian Federation (6), Spain (1), Sweden (35), the United Kingdom (46), United States (59: Alaska, British Columbia, California, Idaho, Maine, Montana, Nevada, New Mexico, New York, Oklahoma, Utah, Virginia)
• Tremadoc of Argentina (6), Canada (19: Alberta, Newfoundland and Labrador, Yukon), China (38), Colombia (1), the Czech Republic (2), France (7), Iran (6), Morocco (1), Norway (2), the Russian Federation (3), Sweden (3), the United Kingdom (1), United States (5: Montana, Texas, Utah, Vermont)
• Cressagian of the United Kingdom (3)
• Skullrockian of Canada (22: British Columbia, Newfoundland), Greenland (1), United States (25: New York, Texas, Utah)
• Ibexian of Norway (2), United States (3: California, Nevada)
• Cambrian to Ordovician of Canada (1: Quebec), the Russian Federation (1)
• Cambrian of Canada (4: Newfoundland and Labrador), China (10), the Russian Federation (3), United States (10: Texas, Utah)
Total: 806 collections including 1177 occurrences