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, Bomakellia, Palaeacmaea, Tentaculitoidea, Yangtziramulus, Scenellopsis, Silicispongea, Eodiorygma, Proarticulata, Rhizostomites, Triradialomorpha, Silicea, Lomosovis, Megathrix, Khasaktidae, Eumetazoa, Helanoichnus, Lidaconus, Parazoa, Erniettomorpha, Bronicella, Convolutubus, Euradiculata, Bilaterialomorpha, Broccoliforma, Yelovichnus, Arboreomorpha, Kimberellomorpha, Deuteronectanebos, Gaojiashania, Mesozoa, Limacites, Chondroplon, Pentaradialomorpha, Lazaichnus, Atalotaenia, Sentularia, Epitheliozoa, Spygoria, Kinzeriidae, Dictyorhabdus, Trichoplax, Macrocypris kayi, Problematica, Persimedusites, Kuckaraukia, Siphonoconcha, Tetraradialomorpha, Porifera, Protolyellia, Petalonamae, Evmiaksia, Gephyrea, Goettingenia, Ventogyrus, Yunnanomedusa, Xidazoon, Nectocarididae, Oligoopilionus, Odontogriphidae, Subtilicyathus, Hadrynichorde, Chenmengella, Hadryniscala, Cnidaria, Somatohelix, Muricassis
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), the Czech Republic (3), Denmark (1), Greenland (9), Mexico (2), Norway (6), Sweden (3), the United Kingdom (8), United States (23: California, Nevada, Pennsylvania, Virginia)
• Waucoban of United States (1: California)
• Caerfai of Canada (1: Northwest Territories)
Total: 69 collections including 72 occurrences