Patagopteryx deferrariisi (Late Cretaceous, 80mya; Alvarenga and Bonaparte 1992, Chiappe 1996, Chiappe 2002, MACN-N-03, 10, 11, 14 and others) was a hen-sized bird originally considered a ratite, but later (Chiappe 1996) nested it between Enantiornithes and Hesperonis. Back then Patagopteryx was one of only a few Cretaceous birds known. Here, with more included taxa, Patagopteryx nests with Struthio, the ostrich, back among the ratites.
Four toes are present.
As in Casaurius pedal ungual 2 is elongate. The pubis tip bends ventrally, like a boot. The anterior skull is unknown but otherwise is similar to Struthio.
Aepyornis, the elephant bird, moves over the the tinamous with this taxon addition.
Alvarenga and Bonaparte 1992. A new flightless land bird from the Cretaceous of Patagonia; pp. 51–64 in K. E. Campbell (ed.), Papers in Avian Paleontology, Honoring Pierce Brodkorb. Natural History Museum of Los Angeles County, Science Series 36.
Chiappe LM 1996. Early avian evolution in the southern hemisphere: Fossil record of birds in the Mesozoic of Gondwana. Memoirs of the Queensland Museum 39:533–556.
Chiappe LM 2002. Osteology of the flightless Patagopteryx deferrariisi from the late Cretaceous of Patagonia (Argentina) pp.281–316 in Mesozoic Birds, Above the Heads of Dinosaurs, Chapter: 13, Editors: Chiappe LM and Witmer LM, University of California Press.