The Skulls of the Cathartid Vultures

Abstract

The New World vultures, family Cathartidae, form a heterogeneous group of large birds which is now limited in its range to the Americas. Only one member, the fossil Plesiocathartes of France, has been taken outside the Western Hemisphere. Including fossils, there have been at various times twelve genera and twenty species within the family. More than half of these are fossil; the oldest is from the Oligocene. An earlier study (in press) of the appendicular skeleton and musculature of the Recent genera indicated that the modern forms are surprisingly diverse in spite of simi- larities in locomotion in the air and on the ground, which are correlated with similari- ties in appendages. Because it was believed that the skull, especially the cranial part, is a more “stable” part of the body and less subject to adaptive change than are the appendages, this region of the skeleton was selected as the basis for a study of relation- ships. In pursuing this investigation it has been necessary, however, to examine some other skeletal parts in order to clarify questions of taxonomy.