On the Mechanical Implications of the Avian Skull and Their Bearing on the Evolution and Classification of Birds

Preliminary investigations dealing with the relationship existing between the morphology of the bird's skull and its kinetic possibilities, appear to show that the thecodont ancestors of Birds, as well as Archaeopteryx were almost certainly akinetic. Kinetism developed early, but at least in some measure independently in the various avian orders. The amount of kinetic movement possible appears to be related to several morphological features, such as the structure of the palate, the relationship of the pterygoid and the braincase, the development of the ossification of the septum nasi, etc., which are usually considered of great taxonomic significance. It is therefore argued that the functional implications of such structures should be carefully considered when studying these features in order to ascertain the evolution and taxonomy of birds.