Re-evaluation of the age at death of immature fossil hominids.

We report here revised chronological ages at death of immature fossil hominids demonstrating for the first time that Plio-Pleistocene hominids had markedly abbreviated growth periods relative to modern man, similar to those of the modern great apes. Previous estimates of age at death for fossil hominids have principally been based on dental eruption, maturation and dental wear criteria for modern man and hence reflect their age in 'human' years. We are now able to estimate the absolute duration of permanent incisor crown formation by observing gross incremental growth features in enamel and thereby apply a timescale to dental developmental events for specimens representing four Plio-Pleistocene fossil hominid taxa. Thus we have derived more reliable-species-specific-estimates of age at death that provide a more secure model on which to base studies of the palaeodemography, growth and maturation of early hominids.