Full reference: B. C. Livezey and R. L. Zusi. 2007. Higher-order phylogeny of modern birds (Theropoda, Aves: Neornithes) based on comparative anatomy. II. Analysis and discussion. Zoological Journal of the Linnean Society 149(1):1-95
Parent taxon: Pygopodotubinares according to B. C. Livezey and R. L. Zusi 2007
Sister taxa: none
Subtaxa: Podicipediformes
Ecology: ground dwelling carnivore
Distribution:
• Quaternary of Argentina (1 collection), Azerbaijan (1), Bolivia (1), Chile (1), East Timor (1), Finland (3), Italy (1), Japan (3), Jordan (1), Mexico (5), New Zealand (3), Peru (1), Puerto Rico (1), the Russian Federation (3), Spain (1), United States (72: Alabama, California, Colorado, Florida, Georgia, New Mexico, Oregon, Texas, Utah, Virginia, Wyoming)
• Blancan of United States (13: California, Florida)
• Pliocene to Pleistocene of Italy (1)
• Pliocene of Italy (1), United States (5: California, Florida, Idaho, North Carolina)
• Hemphillian of United States (1: Kansas)
• Miocene of Ethiopia (1), Spain (1), United States (4: California, Florida)
• Oligocene of Australia (1)
Total: 127 collections including 186 occurrences