Artiopoda - Agnostida - Metagnostidae
Synonyms: Arthrorhachidae Raymond 1913, Geragnostidae Howell 1935, Geragnostinae Howell 1935, Trinodidae Howell 1935
Parent taxon: Condylopygoidea according to E. B. Naimark and T. V. Pegel 2017
See also Harrington and Leanza 1957, Hoel 1999, Jell and Adrain 2002, Owens and Fortey 2009, Robison and Pantoja-Alor 1968 and Whittington et al. 1997
Sister taxa: Agnostidae, Ammagnostidae, Clavagnostidae, Condylopygidae, Diplagnostidae, Doryagnostidae, Glaberagnostus, Glyptagnostus, Leiagnostus, Megagnostus, Phalacromidae, Phalagnostus, Phaldagnostus, Pseudagnostidae, Ptychagnostidae, Spinagnostidae, Valenagnostus
Subtaxa: Anglagnostus Arthrorhachis Chatkalagnostus Corrugatagnostus Dividuagnostus Galbagnostus Geragnostella Geragnostus Granuloagnostus Homagnostoides Trinodus
Ecology: slow-moving epifaunal detritivore
Distribution:
• Uhaku of Sweden (1 collection)
• Dobrotivian of the Czech Republic (2), Portugal (1)
• Liben of the Czech Republic (1)
• Chazyan of Canada (5: Newfoundland and Labrador)
• Whiterockian of Canada (10: Newfoundland and Labrador), United States (2: Nevada)
• Billingen of Estonia (2), Norway (1), the Russian Federation (2), Sweden (2)
• Arenig of Bolivia (1), Canada (2: Newfoundland and Labrador), China (11), France (2), Sweden (4), the United Kingdom (5)
• Arenigian of Argentina (1), China (21), France (2)
• Klabava of the Czech Republic (2), France (1)
• Dawan of China (2)
• Ordovician of Argentina (51), Australia (9), Belgium (2), Canada (7: Alberta, Newfoundland, Newfoundland and Labrador, Northwest Territories, Northwest Terrorities, Yukon), China (82), Colombia (1), the Czech Republic (12), Denmark (3), France (9), Iran (2), Ireland (8), Italy (2), Kazakhstan (1), Mexico (1), Morocco (2), Norway (19), Poland (1), the Russian Federation (6), Spain (6), Sweden (58), the United Kingdom (30), United States (42: California, Maine, Montana, Nevada, New Mexico, Oklahoma, Texas, Utah, Vermont, Virginia)
• Ibexian of Norway (1), United States (1: California)
• Skullrockian of Argentina (1)
• Cambrian to Ordovician of Argentina (5)
• Cambrian of Australia (1), Canada (1: Newfoundland and Labrador), China (5), United States (10: Alaska, Montana, Nevada, New Mexico, Texas, Utah)
Total: 462 collections including 556 occurrences