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

  • Tinamidae (tinamous)
  • Casuariidae (Emu & 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 follows Almeida et al. (2021). It should be noted, however, that while protein-coding nuclear gene sequences indeed pointed to tinamous and casuariids as sister clades,  phylogenetic reconstructions based on non-coding nuclear DNA and mitogenomes, respectively, recovered Tinamidae and Rheidae as sister clades (Wang et al., 2019). Takezaki (2023) favoured a sister-group relationship between tinamous on the one hand and kiwi, cassowaries and Emu on the other hand. Simmons et al. (2021) consider palaeognath phylogeny still unsettled. 

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

Struthionidae (ostriches) are traditionally regarded as a single species, Struthio camelys. However, mitochondrial DNA seems to justify the distinction of two species, Struthio camelus (Common Ostrich) and Struthio molybdanes (Somali Ostrich). The two species 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 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, except the 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 clock during the night. Paternal care is a fairly unusual reproductive trait that is considered to be restricted to species where relating opportunities are rare for both species and particularly scarce for males (Owens, 2002). 

Palaeognaths comprise a number of interesting fossil taxa: 

  • Elephant birds (Aepyornithidae) are a recently extinct family from Madagascar that comprised the genera Mullerornis and Aepyornis (Yonezawa et al., 2017). Interestingly, ancient DNA has been extracted from subfossil elephant-bird remains (Grealy et al., 2017; Yonezawa et al., 2017). 
  • Moas (Dinornithidae) are an extinct taxon from New Zealand. They probably became extinct 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)


Burleigh JG, Kimball RT, and Braun EL (2015), Building the avian tree of life using a large-scale, sparse supermatrix, Mol. Phylogenet. Evol. 84, 53-63. (abstract)

Choi S, Hauber ME, Legendre LJ, Kim NH, Lee YN, and Varricchio DJ (2023), Microstructural and crystallographic evolution of palaeognath (Aves) eggshells, Evol. Biol. (free 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)


Kimball RT, Oliveros CH, Wang N, White ND, Barker FK, Field DJ, Ksepka DT, Chesser RT, Moyle RG, Braun MJ, Brumfield RT, Faircloth BC, Smith BT, and Braun EL (2019), A phylogenomic supertree of birds, Diversity 11, e:109. (free 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)


Phillips MJ, Gibb GC, Crimp EA, and Penny D (2010), Tinamous and moa flock together: mitochondrial genome sequence analysis reveals independent losses of flight among ratites, Syst. Biol. 59, 90-107. (free 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)


Reddy S, Kimball RT, Pandey A, Hosner PA, Braun MJ, Hackett SJ, Han KL, Harshman J, Huddleston CJ, Kingston S, Marks BD, Miglia KJ, Moore WS, Sheldon FH, Witt CC, Yuri T, and Braun EL (2017), Why do phylogenomic data sets yield conflicting trees? Data type influences the avian Tree of Life more than taxon sampling, Syst. Biol. 66, 857-879. (free pdf)


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)


Simmons MP, Springer MS, and Gatesy J (2021), Gene-tree misrooting drives conflicts in phylogenomic coalescent analyses of palaeognath birds, Mol. Phylogenet. Evol. 167, e:107344. (abstract)


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, e:643296. (pdf)

Takezaki N (2023), Effect of different types of sequence data on palaeognath phylogeny, Genome Biol. Evol. e:evad092. (free pdf)

Urantówka AD, Kroczak A, and Mackiewicz P (2020) New view on the organization and evolution of Palaeognathae mitogenomes poses the question on the ancestral rearrangement in Aves, BMC Genomics 21, e:874. (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)


Widrig K, and Field DJ (2022), The evolution and fossil record of palaeognathous birds (Neornithes: Palaeognathae), Diversity 14, e:105. (pdf) 


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)