The anatomy of the middle ear of the tinamiformes (Aves: Tinamidae)

The morphology of the middle ear region including the basicranium and quadrate of tinamous is compared among ratites and flying birds belonging to the Procellariiformes, Sphenisciformes, Pelecaniformes, and Ciconiiforms. The middle ears of tinamous and ratites share a number of important characters including absence of a separate foramen for the glossopharyngeal nerve; eustachian tube, carotid artery, and stapedial artery encased in bone; and a metotic process with vascular canals or notches. Outgroup analysis confirms these characters as synapomorphies. These data support the position that the Tinami and Ratiti form a monophyletic assemblage.