Aepyornis maximus (Geoffroy Saint-Hilaire) is the recently extinct elephant bird restricted to Madagascar. It is the heaviest of all birds and 3m tall. Long considered a ratite related to Apteryx, here this taxon is recovered asa giant tinamou.

Recent papers on a very large Madagascar egg (Balanoff 2003, Balanoff and Rowe 2007) with embryo includes some palatal elements.

Aepyornis embryo from Madagascar (Balanoff 2003, Balanoff and Rowe 2007) was originally considered an embryo Aepyornis based on egg size and location. Here, the skull of the embryo also has the inflated squamosals found in Struthio, the ostrich.

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 between Enantiornithes and Hesperonis. Here, with more included taxa, Patagopteryx nests with Struthio, the ostrich, 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.

Paelotis weigelti (Lambrecht 1928; middle Eocene; GM 4362) was originally described as an extinct bustard, like Ardeotis. Later it was referred to the ostrich clade.

Struthio camelus (Linneaus 1758) The extant ostrich is the largest and fastest living bird. Weight: up to 320 lbs (115 kg). Height: 9 feet (2.8m). Speed:43 mph (70 km/h). It is most closely related to other flightless extant birds. Here it nests as a sister to Gallus. This is the only living bird with two toes. Skull courtesy of Digimorph.org and used with permission.

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.

Andrews CW 1896. On the skull, sternum, and shoulder-girdle of Aepyornis. Ibis, Seventh Series, 2:376-389.

Balanoff AM 2003. Osteological description of an embryonic elephant bird (Ratitae: Aepyornis) using high-resolution X-ray computed tomography, with a discussion of growth in Aepyornis. M.S. thesis, The University of Texas, Austin, Texas, 175 pp.

Balanoff AM and Rowe T 2007. Osteological description of an embryonic skeleton of the extinct elephant bird, Aepyornis (Palaeognathae: Ratitae). Journal of Vertebrate Paleontology 27(sp9):1–53.

Chiappe LM 1996a. Late Cretaceous birds of southern South America: anatomy and systematics of Enantiornithes and Patagopteryx deferrariisi; pp. 203–244 in G. Arratia (ed.), Contributions of Southern South America to Vertebrate Paleontology, Münchner Geowissenschaftliche Abhandlungen Volume 30.

Chiappe LM 1996b. 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.

Cracraft J 1981. Toward a phylogenetic classification of the recent birds of the world (Class Aves).Auk98: 681–714.

Geoffroy Saint-Hilaire I 1851. [Note sur les onze espèces nouvelles do Trochilidés de M. Bourcier.] Compt. Rend. de l'Acad. Sci 32:188.

Lambrecht K 1928. Palaeotis weigelti n. g. sp., eine fossil trappe aus der mitteleozanen Braunkohle des Geiseltales. Jahrbuch hallesch. Verband., Halle, n.s., 7:11.

Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

Mayr G 2004. Morphological evidence for sister group relationship between flamingos (Aves: Phoenicopteridae) and grebes (Podicipedidae). Zoological Journal of the Linnean Society. 140 (2): 157–169. doi:10.1111/j.1096-3642.2003.00094.x. ISSN 0024-4082.

Mayr G 2006. The contribution of fossils to the reconstruction of the higher level phylogeny of birds. Species, Phylogeny and Evolution 1 (2006):59–64.

Mayr G 2015. Cranial and vertebral morphology of the straight-billed Miocene phoenicopteriform bird Palaelodus and its evolutionary significance. Zoologischer Anzeiger – A Journal of Comparative Zoology. 254:18–26.

Milne-Edwards A 1863. Mémoire sur la distribution géologique des oiseaux fossiles et description de quelques espèces nouvelles. Annales des Sciences Naturelles (in French). 4 (20): 132–176.

Milne-Edwards, A 1867-1871. Recherches anatomiques et paleontologiques pour servir a l’histoire des oiseaux fos- siles de la France (Paris, G. Masson).

Olson SL, Feduccia A 1980a. Relationships and evolution of flamingos (Aves: Phoenicopteridae). Smithsonian Contributions to Zoology 316: 1–73.

Temminck 1815. Histoire naturelle generale des pigeons et des gallinaces.
Accompagne de planches anatomiques. 3: 552–747

wiki/Ostrich
wiki/Aepyornis
wiki/Palaelodus
wiki/Palaeotis