ORDINAL AFFINITIES OF THE AEGIALORNITHIDAE

The Aegialornithidae of the Eocene-Oligocene, previously regarded as swifts, have been transferred by Brodkorb (1971) to the nightjar order Caprimulgiformes. The fossil forelimb bones representing this early family have now been compared with those of recent species of the true swifts and tree swifts (Apodi in Apodiformes) and with nightjars, Oilbirds and frogmouths (Caprimulgiformes). The corresponding bones in swifts differ consistently from those of nightjars in the greater development of various prominences for muscle attachment. In all critical characters the fossil bones resemble those of swifts, and it is concluded that the Aegialornithidae should be reinstated as a family of the Apodiformes.