Full reference: E. L. Yochelson. 1977. Agmata, a proposed extinct phylum of Early Cambrian age. Journal of Paleontology 51:437-454
Parent taxon: Metazoa according to E. L. Yochelson 1977
Sister taxa: Bilateria, Diploblastica, Homoblastica, Hyolithelminthida, Vertebrosa, Westgardia, Hadrynichorde, Gaojiashania, Trichoplax, Bronicella, Lazaichnus, Tentaculitoidea, Dorfopterus, Limacites, Persimedusites, Goettingenia, Bilaterialomorpha, Chondroplon, Tetraradialomorpha, Yunnanomedusa, Cnidaria, Yelovichnus, Porifera, Lomosovis, Silicea, Problematica, Triradialomorpha, Gephyrea, Yangtziramulus, Epitheliozoa, Ventogyrus, Proarticulata, Eodiorygma, Oligoopilionus, Khasaktidae, Pentaradialomorpha, Deuteronectanebos, Odontogriphidae, Eumetazoa, Spygoria, Mesozoa, Muricassis, Kinzeriidae, Euradiculata, Kimberellomorpha, Lidaconus, Xidazoon, Subtilicyathus, Siphonoconcha, Hadryniscala, Atalotaenia, Megathrix, Helanoichnus, Arboreomorpha, Erniettomorpha, Bomakellia, Somatohelix, Sentularia, Silicispongea, Macrocypris kayi, Petalonamae, Parazoa, Evmiaksia, Broccoliforma, Chenmengella, Scenellopsis, Kuckaraukia, Dictyorhabdus, Protolyellia, Palaeacmaea, Convolutubus
Subtaxa: Salterellidae Volborthellida Volborthellidae
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 Greenland (1), United States (1: California)
Total: 70 collections including 73 occurrences