secundum Sibley & Ahlquist, 1990

Parvclassis: Ratitae
Ordo: Struthioniformes
Familiae: Apterygidae – Casuariidae – Rheidae – Struthionidae

secundum Livezey & Zusi, 2007

Subcohors: Ratitae
Ordo: Struthioniformes
Familiae: Rheidae – Struthionidae

secundum Cracraft, 2013

Superordo: Struthionimorphae
Ordo: Struthioniformes
Familia: Struthionidae

Primary references

• Latham, J. 1790. Index ornithologicus, sive systema ornithologiæ; complectens avium divisionem in classes, ordines, genera, species, ipsarumque varietates: adjectis synonymis, locis, descriptionibus, &c. Volumen II: 467–920. Londini. (Leigh & Sotheby). BHL Reference page. 

Additional references

• Sibley, C.G. & Ahlquist, J.E. 1990. Phylogeny and Classification of Birds: A Study in Molecular Evolution. Yale University Press. ISBN 0-300-04085-7 Reference page. 

• Livezey, B.C. & Zusi, R.L. 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. DOI: 10.1111/j.1096-3642.2006.00293.x PMC: 2517308. PMID: 18784798. Reference page. 

• Cracraft, J. 2013. Avian Higher-level Relationships and Classification: Nonpasseriforms. xxi–xliii. In: Dickinson, E.C. & Remsen, J.V. (eds.) 2013. The Howard & Moore Complete Checklist of the Birds of the World. 4th Edition. Volume 1: Non-passerines. Eastbourne: Aves Press. ISBN 978-0-9568611-0-8 Reference page. 

• Yuri, T., Kimball, R.T., Harshman, J., Bowie, R.C.K., Braun, M.J., Chojnowski, J.L., Han, K.-L., Hackett, S.J., Huddleston, C.J., Moore, W.S., Reddy, S., Sheldon, F.H., Steadman, D.W., Witt, C.C. & Braun, E.L. 2013. Parsimony and Model-Based Analyses of Indels in Avian Nuclear Genes Reveal Congruent and Incongruent Phylogenetic Signals. Biology 2(1): 419–444. DOI: 10.3390/biology2010419 ResearchGate Reference page. 

• Mayr, G. 2019. Hindlimb morphology of Palaeotis suggests palaeognathous affinities of the Geranoididae and other "crane-like" birds from the Eocene of the Northern Hemisphere. Acta Palaeontologica Polonica 64(4): 669–678. DOI: 10.4202/app.00650.2019 ResearchGate Reference page. 

• Widrig, K. & Field, D.J. 2022. The Evolution and Fossil Record of Palaeognathous Birds (Neornithes: Palaeognathae). Diversity 14(105). 1–69. DOI: 10.3390/d14020105 Reference page. 

Links

• Ratites: Ostriches to tinamous – IOC World Bird List v12.1