Palaeognathae

The Palaeognathae, or paleognaths (from Ancient Greek "palaió-" "old" + "gnáthos" "jaw") is one of two living clades of birds: the other is the Neognathae. Together, the two clades make up the clade Neornithes. 
Palaeognathae includes five living branches of flightless birds (plus two extinct clades), called ratites, and one flying lineage, the Neotropic tinamous.
There are three extinct groups that are undisputed members of Palaeognathae: the Lithornithiformes, the Dinornithiformes (moas) and the Aepyornithiformes (elephant birds).