Full reference: C. D. Walcott. 1886. Second contribution to the studies on the Cambrian faunas of North America. United States Geological Survey Bulletin 30:1-365
Parent taxon: Agmata according to E. L. Yochelson and G. N. Kisselev 2003
See also Peel and Berg-Madsen 1988, Skovsted 2006 and Yochelson 1977
Sister taxa: Volborthellida, Volborthellidae
Subtaxa: Ellisell Salterella Volborthella
Distribution:
• Ordovician of United States (1: Tennessee collection)
• Cambrian of Argentina (1), Canada (10: Labrador, Neufundland and Labrador, Newfoundland and Labrador, Quebec, Yukon Territory), Czechia (3), Denmark (1), Greenland (9), Mexico (2), Norway (6), Sweden (3), the United Kingdom (8), United States (23: California, Nevada, Pennsylvania, Virginia)
• Caerfai of Canada (1: Northwest Territories)
• Waucoban of United States (1: California)
Total: 69 collections including 72 occurrences