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Fossil record

Flight-capable lithornithids from the Paleocene and Eocene epochs appear to have been structurally the most similar precursors to the tinamous, and may have been ancestral to them as well as to the ratites, though their precise relationships are unclear. The earliest unequivocally Tinamiforme fossil material dates from the Miocene, but flightless ratite-like taxa from the Paleocene may belong to this group.

Several tinamou fossils have been found in the 16–17 Mya Early-Middle Miocene Santa Cruz Formation and the contemporary, or slightly older, Pinturas Formation, in Santa Cruz Province of Argentinian Patagonia, including a tinaminid, Crypturellus reai. Associated fossils indicate that the local palaeoenvironment at the beginning of this period was characterised by a humid, subtropical climate, with forest vegetation, becoming drier and more open with time. Some of the tinamou fossil material appears to be intermediate between the two subfamilies, suggesting that the period coincides with the origins of the radiation of the Nothurinae into the expanding open-country habitats.

Nothurine fossils referrable to Eudromia and Nothura have been found in the Late Miocene Cerro Azul Formation from the Pampean region of central-southern Argentina. Tinamous described from Pliocene material include Eudromia olsoni Tambussi & Tonni, 1985, Nothura parvulus Rovereto, 1914, and Nothura padulosa Mercerat, 1897. The Pliocene fossil genera Cayetornis Brodkorb and Tinamisornis Rovereto have been synonymized with Nothura and Eudromia respectively. Fossils having affinities with several extant genera have been found in Pleistocene deposits.