Dental and skeletal growth in early fossil hominins.

Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK.

Early fossil hominins have often been assigned a chronological age on the basis of modern human data for tooth eruption. Better data and more sophisticated methods are now available to estimate their chronological age from modern human standards for stages of mineralization of individual teeth developing within the jaws. However, while comparisons with modern human dentitions are interesting, they can also be misleading as early hominin teeth and dentitions did not grow like modern human teeth. Chronological age can also be estimated using the microanatomy of tooth enamel and root dentine. Counts of incremental markings in enamel predict much younger ages at death for early fossil hominins than those based on modern human radiographic standards of dental development. Comparative evidence from the skeleton suggests that a greater proportion of adult body mass and stature was achieved earlier in the growth period of fossil hominins than it is in modern humans. The combined skeleto-dental evidence provides the basis for a hypothesis that the earliest hominins grew more like modern great apes, but that Homo erectus had a slightly more prolonged period of growth, and which was still not totally modern human-like in its pattern or timing.