Neognathae are birds in the subclass Neornithes. The Neognathae include almost all living birds: their sister taxon Palaeognathae has just the tinamou and the flightless ratites.
There are nearly 10,000 species of neognaths. Since the Cretaceous they have undergone an adaptive radiation. This has produced the variety of form, function, and behavior which we see today. The Passeriformes (perching birds) are the largest order of land vertebrates. They are some 60% of living birds.