INVESTIGATION INTO THE RELATIONSHIP BETWEEN PERIKYMATA COUNTS AND CROWN FORMATION TIMES

This study reports on a sample of 12 modern human incisors (from two archaeological sites) that were viewed with a scanning electron microscope and whose perikymata were counted. These 12 incisors more than doubles the previously published sample size of modern human incisors that have served as the published standard for perikymata number in human incisors and have been employed to define taxonomic relationships in fossil hominids. All previously published fossil specimens fall within the expanded range of modern human perikymata counts and can no longer be considered distinctively nonhuman in dental formation time. Five neandertal incisors from the Krapina site in Croatia, Yugoslavia, were also examined. These incisors substantially expand the previous data base for counts of perikymata in Homo sapiens neanderthalensis, likewise overlapping the previously published modern human range. Finally, the validity of methods that have been employed for deriving crown formation times from perikymata counts in fossil hominines is called into question. Utilizing the presently known perikymata ranges for modern humans, these methods do not predict the range of known crown formation times of modern humans as assessed from studies of living children.