Allometry and heterochrony in the African apes.

In this work allometry and heterochrony are integrated in an analysis of ontogenic and interspecific morphological patterns in the African apes. The relationship between the interspecific differences in adult morphology and the differences in underlying patterns of growth allometries, body weight growth rates, and developmental chronologies is investigated. Results indicate that rate hypermorphosis, or the extension of ancestral allometries into new size/shape ranges with no increase in the duration of ontogeny, underlies many of the interspecific differences in form among the African apes. In addition, the need for further clarification of the processes of heterochrony is stressed by distinguishing between rate and timing differences. These distinctions and processes are illustrated and discussed using the morphological data on the African apes.