The superorder Palaeognathae is restricted to the order Struthioniformes comprising the following families: 

  • Tinamidae (tinamous)
  • Casuariidae (Emu and cassowaries)
  • Apterygidae (kiwi)
  • Rheidae (rheas)
  • Struthionidae (ostriches)

Genus-level timetree of extant Palaeognathae based on Prum et al. (2015), and Kuhl et al. (2021), with the distribution of each family being indicated by the colour-code used throughout this website (see Distribution code). Divergence times follow Wang et al. (2019), and Kuhl et al. (2021), which differ significantly from Prum et al. (2015). The intrinsic phylogeny of Tinamidae represents the results of Almeida et al. (2021). 

Tinamidae (tinamous) are remarkable for being the only volant birds in a group of otherwise cursorial birds. However, the flying ability is very poor. Unfortunately, the phylogenetic position of tinamous within the order couldn’t be resolved with certainty, despite considerable efforts. 

Struthionidae (ostriches) are traditionally regarded as a single species, Struthio camelus. However, mitochondrial DNA seems to justify the distinction of two species, Struthio camelus (Common Ostrich) and Struthio molybdanes (Somali Ostrich). Ostriches are thought to have separated from each other by the formation of the East African Rift Valley some 4 Ma. Reaching a top speed of about 70 km/h (45 mph), ostriches are the fastest running birds in the world. 

Extant ostriches are restricted to Africa, while the remaining palaeognaths (Notopalaeognathae) occur in South America, Australia, and New Zealand. 

All palaeognaths, with the exception of Struthionidae, exhibit paternal care, with incubation of the eggs relying entirely on the male (Birchard et al., 2013). In ostriches the hen incubates during the day and the cock during the night. Paternal care is a fairly unusual reproductive trait that is considered to occur in species where remating opportunities are rare for both sexes and particularly scarce for males (Owens, 2002). 

Palaeognaths comprise a number of interesting fossil taxa: 

  • Elephant birds, Aepyornithidae, are a recently extinct avian family in Madagascar that comprised the genera Mullerornis and Aepyornis. (Yonezawa et al., 2017). Interestingly, ancient DNA has been successfully extracted from sub-fossil elephant-bird remains (Grealy et al., 2017; Yonezawa et al., 2017). 
  • Moas, Dinornithidae, are an extinct taxon in New Zealand. They probably became extinct just some 150 years after Polynesian settlement. 
  • Lithornithidae represent an extinct taxon from North America and Europe. 


Almeida FC, Porzecanski AL, Cracraft JL, and Bertelli S (2021), The evolution of tinamous (Palaeognathae: Tinamidae), in light of molecular and combined analyses, Zool. J. Linn. Soc., e:zlab080. (abstract)

Baker AJ, Haddrath O, McPherson JD, and Cloutier A (2014), Genomic support for a Moa-Tinamou clade and adaptive morphological convergence in flightless ratites, Mol. Biol. Evol. 31, 1686-1696. (pdf)


Bertelli S, and Porzecanski AL (2003), Tinamou (Tinamidae) systematics: a preliminary combined analysis of morphology and molecules, Ornitol. Neotrop. 15 (suppl.), 293-299. (pdf)


Bertelli S, Chiappe LM, and Mayr G (2014), Phylogenetic interrelationships of living and extinct Tinamidae, volant palaeognathous birds from the New World, Zool. J. Linn. Soc. 172, 145-184. (abstract)


Birchard GF, Ruta M, and Deeming DC (2013), Evolution of parental incubation behaviour in dinosaurs cannot be inferred from clutch mass in birds, Biol. Lett. 9 (4). (abstract)


Braun EL, and Kimball RT (2020) Data types and the phylogeny of Neoaves. Preprints 2020, 2020110423. (pdf)


Cloutier A, Sackton TB, Grayson P, Clamp M, Baker AJ, and Edwards SV (2019), Whole-genome analyses resolve the phylogeny of flightless birds (Palaeognathae) in the presence of an empirical anomaly zone, Syst. Biol. 68, 937-955. (abstract) 

Freitag S, and Robinson TJ (1993), Phylogeographic patterns in mitochondrial DNA of the Ostrich (Struthio camelus), Auk 110, 614-622. (pdf)


Grealy A, Phillips M, Miller G, Gilbert MTP, Rouillard JM, Lambert D, Bunce M, and Haile J (2017), Eggshell palaeogenomics: palaeognath evolutionary history revealed through ancient nuclear and mitochondrial DNA from Madagascan elephant bird (Aepyornis sp.) eggshell, Mol. Phylogen. Evol. 109, 151-169. (abstract)


Haddrath O, and Baker AJ (2012), Multiple nuclear genes and retroposons support vicariance and dispersal of the palaeognaths, and Early Cretaceous origin of modern birds. Proc. Royal Soc. B 279, 4617-4625. (pdf)


Heine C, Zoethout J, and Müller RD (2013), Kinematics of the South Atlantic rift, Solid Earth 4, 215-253. (pdf)


Kuhl H, Frankl-Vilches C, Bakker A, Mayr G, Nikolaus G, Boerno ST, Klages S, Timmermann B, and Gahr M (2021), An unbiased molecular approach using 3'UTRs resolves the avian family-level tree of life, Mol. Biol. Evol. 38, 108-127. (pdf)


Mitchell KJ et al. (2014), Ancient DNA reveals elephant birds and kiwi are sister taxa and clarifies ratite bird evolution, Science 344, 898(abstract)


Owens IPF (2002), Male-only care and classical polyandry in birds: phylogeny, ecology and sex differences in remating opportunities, Phil. Trans. R. Soc. Lond. B (2002) 357, 283-293(pdf)


Pratt TK, and Beehler BN (2014), "Birds of New Guinea", 2nd edition,  Princeton University Press(link)


Prum RO, Berv JS, Dornburg A, Fields DJ, Townsend JP, Lemmon EM, and Lemmon AR (2015), A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. Nature 526, 569-573. (abstract)


Ramstad KM, and Dunning LT (2020), Population genomics advances and opportunities in conservation of kiwi (Apteryx spp.)In: Population Genomics(Rajora OP, ed.), pages 1-29, Springer, Cham. (abstract)


Sackton TB, Grayson P, Cloutier A, Hu Z, Liu JS, Wheeler NE, Gardner PP, Clarke JA, Baker AJ, Clamp M, and Edwards SV (2019), Convergent regulatory evolution and loss of flight in paleognathous birds. Science 364, 47-78. (link)


Smith JV, Braun EL, and Kimball RT (2013), Ratite nonmonophyly: independent evidence from 40 novel loci. Syst. Biol. 62, 35-49. (pdf)


Springer MS, and Gatesy J (2019), Retroposon insertions within a multispecies coalescent framework suggest that ratite phylogeny is not in the 'anomaly zone'. bioRxiv, . (pdf)


Wang Z, Zhang J, Xu X, Witt C, Deng Y, Chen D, Meng G, Feng S, Szekely T, Zhang G, and Zhou Q (2019), Phylogeny, transposable element and sex chromosome evolution of the basal lineage of birds. BioRxiv. (pdf)

Wang Z, Zhang J, Xu X, Witt C, Deng Y, Chenc G, Meng G, Feng S, Xu L, Szekely T, Zhang G, and Zhou Q (2021), Phylogeny and sex chromosome evolution of Palaeognathae, J Genet. Genomics . (abstract)

Yonezawa T, Segawa T, Mori H, Campos PF, Hongoh Y, Endo H, Akiyoshi A, Kohno N, Nishida S, Wu J, Jin H, Adachi J, Kishino H, Kurokawa K, Nogi Y, Tanabe H, Mukoyama H, Yoshida K, Rasoamiaramanana A, Yamagishi S, Hayashi Y, Yoshida A, Koike H, Akishinonomiya F, Willerslev E, and Hasegawa M (2017), Phylogenomics and morphology of extinct paleognaths reveal the origin and evolution of the ratites. Curr. Biol. 2768-77. (pdf)