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, Proarticulata, Goettingenia, Dictyorhabdus, Deuteronectanebos, Limacites, Epitheliozoa, Macrocypris kayi, Broccoliforma, Palaeacmaea, Mesozoa, Protolyellia, Yunnanomedusa, Yelovichnus, Bomakellia, Sentularia, Chondroplon, Chenmengella, Persimedusites, Triradialomorpha, Bilaterialomorpha, Petalonamae, Helanoichnus, Eodiorygma, Oligoopilionus, Bronicella, Hadryniscala, Pentaradialomorpha, Gaojiashania, Ventogyrus, Porifera, Muricassis, Tetraradialomorpha, Dorfopterus, Atalotaenia, Megathrix, Lazaichnus, Kuckaraukia, Euradiculata, Kimberellomorpha, Khasaktidae, Scenellopsis, Lidaconus, Trichoplax, Somatohelix, Xidazoon, Siphonoconcha, Convolutubus, Yangtziramulus, Spygoria, Silicea, Parazoa, Evmiaksia, Hadrynichorde, Silicispongea, Cnidaria, Kinzeriidae, Eumetazoa, Subtilicyathus, Problematica, Gephyrea, Erniettomorpha, Lomosovis, Odontogriphidae, Arboreomorpha, Tentaculitoidea
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)
• Waucoban of Greenland (1), United States (1: California)
• Caerfai of Canada (1: Northwest Territories)
Total: 70 collections including 73 occurrences