Quantification of the morphological evolution of the Hominid skull and heterochronies

Comparisons of adult skulls of various species of great apes, fossil hominids and modern humans in the sagittal, Francfort and ortho-sagittal planes reveal a series of three separate organisation plans: 'Great Ape', 'Australopithecine' and 'Homo', the latter including primitive men (Homo ergaster-erectus-neandertalensis) and modern humans (Homo sapients). Morphological changes between these plans are quantified for the first time here by vector fields. This study confirms the existence of cranio-facial contraction, which occurs as a series of leaps. The juvenile morphology of the great ape skull is broadly preserved in adult Homo sapiens, suggesting that numerous heterochromies have occurred in mosaic during ontogeny (hypermorphosis, hypomorphosis, post-displacements). (C) Academie des sciences/Elsevier, Paris.