All modern birds lie within the crown group Aves (alternately Neornithes), which has two subdivisions: the Palaeognathae, which includes the flightless ratites (such as the ostriches) and the weak-flying tinamous, and the extremely diverse Neognathae, containing all other birds. These two subdivisions are often given the rank of superorder, although Livezey and Zusi assigned them "cohort" rank. Depending on the taxonomic viewpoint, the number of known living bird species varies anywhere from 9,800 to 10,050. COUNT 4
QSN1 All modern birds lie within which crown group? ANS1 Aves QSN2 What is another name for Aves? ANS2 Neornithes QSN3 The two subdivisions of what group include Palaeognathae and Neognathae? ANS3 Aves QSN4 What is the number range of living bird species? ANS4 9,800 to 10,050