Studies of craniofacial development and evolution

In this paper we review the basic mechanisms underlying the post-natal growth of the cranium and consider two recent advances in methodology which offer the prospect of improving our ability to study growth changes in the skull. Recent advances in techniques for the study of craniofacial remodelling are combined with a numerical approach to the study of shape changes, the thin plate spline, in order to examine the correspondence between the spatial distribution of resorbing fields and bone displacements in the sooty mangabey, Cercocebus atys. Our results indicate that in ontogeny, as in phylogeny, changing patterns of bone displacements are first accommodated by changing rates of cortical remodelling in old world monkeys. Only later, when displacements are more extreme do remodelling fields transform from depository to resorptive. This study demonstrates that transformation grids may be usefully combined with scanning electron microscopy of cortical surfaces in studies of craniofacial development.