Parent taxon: Hydrozoa according to J.E.N. Veron 2000
See also Rehfeld and Ernst 1998 and Sepkoski 2002
Sister taxa: Actinulida, Delheidia, Fistulella, Graptogeitonia, Hydrocorallinae, Hydroida, Hydroidolina, Kerunia, Lemniscaterina, Likinia, Limnomedusae, Milleporidae, Narcomedusae, Nigriporellidae, Plumalina, Rhizostromella, Roseoporella, Siphonophorida, Sphaeractinida, Spongiomorphida, Stoliczkiella, Stylasterina, Trachylinida, Tubulariae, Tubuloparietes
Subtaxa: Axoporidae Heterastrididae Millepora Palaeomillepora Subaxopora
Ecology: stationary epifaunal carnivore-suspension feeder
Distribution:
• Quaternary of Antigua and Barbuda (1 collection), Australia (6), the Bahamas (2), Barbados (2), Belize (2), Brazil (1), Cape Verde (4), Cayman Islands (1), Cook Islands (1), the Dominican Republic (2), Egypt (9), French Polynesia (2), Guam (1), Haiti (1), Japan (2), Kiribati (1), Mauritius (2), the Netherlands Antilles (1), New Caledonia (2), Panama (2), Saudi Arabia (7), the Seychelles (5), Tuvalu (1), United States (4: Florida), Vanuatu (1), Virgin Islands (1), Virgin Islands (3)
• Pliocene to Pleistocene of Costa Rica (3)
• Pliocene of Costa Rica (1), the Marshall Islands (1), United States (1: Florida)
• Miocene of Colombia (3), France (1), Israel (1), the Marshall Islands (2), Morocco (1), New Zealand (1)
• Oligocene of Italy (6), Jamaica (2)
• Eocene of France (1), Germany (1), Italy (2), Jamaica (3), Panama (1), Spain (1), the United Kingdom (1)
• Cretaceous of Spain (2), Ukraine (1)
• Jurassic of Croatia (1), United States (1: Idaho)
• Triassic of Austria (2), Canada (2: British Columbia), Cyprus (1), Hungary (1), Indonesia (4), Iran (5), Mexico (3), New Caledonia (1), Oman (2), the Russian Federation (4), Tajikistan (1), the United Arab Emirates (1), United States (29: Alaska)
• Permian of China (2)
• Devonian of Germany (1)
Total: 164 collections including 170 occurrences