Cranial Evolution in the Apes

The discussion of cranial evolution in the apes is organized around two key themes in this chapter. The first is that the phylogenetic relationships and even bracketed divergence times among the primary lineages of apes are now relatively robustly established, due largely to advances in biomolecular systematics. A second emphasis is that the understanding of hominoid evolution has long been hindered by the relative lack of attention given to the "lesser apes" (Hylobatidae), which has in turn tended to obfuscate the character novelties associated with the rise of the "great apes" (Hominidae). The chapter examines in greater detail some selected features of cranial anatomy, which have been suggested at one time or another as key defining novelties (synapomorphies) of the primary hominoid clades and lineages.