Palaeognathae

Palaeognathae (; ) is an infraclass of birds, called paleognaths or palaeognaths, within the class Aves of the clade Archosauria. It is one of the two infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contains five extant orders consisting of four flightless lineages (plus two that are extinct), termed ratites, and one flying lineage, the Neotropic tinamous. There are 47 species of tinamous, five of kiwis (Apteryx), three of cassowaries (Casuarius), one of emus (Dromaius) (another became extinct in historic times), two of rheas (Rhea) and two of os

Notopalaeognathae is a clade that contains the order Rheiformes (rheas), the clade Novaeratitae (which includes the cassowaries and emus, the kiwis, and the extinct elephant birds), and the clade Dinocrypturi (comprising the tinamous and the extinct moas). Notopalaeognathae was named by Yuri et al. (2013) and defined in the PhyloCode by Sangster et al. (2022) as "the least inclusive crown clade containing Rhea americana, Tinamus major, and Apteryx australis". The exact relationships of this group, including its recently extinct members, have only recently been uncovered. The two lineages endem

Nothurinae or aridland tinamous is one of two subfamilies of the Tinamidae family, the other being Tinaminae. It contains eighteen species in six genera. The six genera are: Rhynchotus (2 species) Nothoprocta (6 species) Nothura (5 species) Taoniscus (monotypic) – dwarf tinamou Eudromia (2 species) Tinamotis (2 species)

Tinaminae, the forest tinamous, is one of two subfamilies of the family Tinamidae, the other being Nothurinae.

Proapteryx micromeros is an extinct kiwi known from the 16–19 million-year-old early Miocene sediments of the St Bathans Fauna of Otago, New Zealand.

Eremopezus is a prehistoric bird genus of uncertain affinities. It is known only from the fossil remains of a single species, the huge and presumably flightless Eremopezus eocaenus. This was found in Upper Eocene Jebel Qatrani Formation deposits around the Qasr el Sagha escarpment, north of the Birket Qarun lake near Faiyum in Egypt. The rocks its fossils occur in were deposited in the Priabonian, with the oldest dating back to about 36 million years ago (Ma) and the youngest not less than about 33 Ma.

Remiornis heberti is an extinct species of paleognath bird from the Paleocene of France. It is a species comparable in size to modern rheas, and possibly related to another European Paleogene ratite, Palaeotis. In spite of being one of the oldest ratites in the world, it is often ignored for Gondwana vicariance narratives.