Perikymata distribution in Homo with special reference to the Xujiayao juvenile.

Abstract

This study investigates where the Xujiayao juvenile (I(1) and C(1) ) fits into the array of perikymata distribution patterns found within the genus Homo. In addition to the I(1) and the C(1) of the Xujiayao juvenile, this study includes samples of early Homo (H. rudolfensis and H. erectus), Neandertals, early modern humans (Qafzeh), and recent modern humans from Southern Africa, Newcastle (UK), and North America (Inupiaq, AK). Three sets of analyses were undertaken, including a comparison of percentage of perikymata in the cervical half of the crown, repeated measures analysis of the percentage of total perikymata in each decile, and canonical variates analysis using both total perikymata number and the percentage of perikymata in the cervical half of the crown. The I(1) and C(1) of early Homo and Neandertals have a lower percentage of perikymata in the cervical half of the crown than modern human samples. Repeated measures analysis reveals clear distinctions in the distribution of perikymata between the modern human and fossil samples. Canonical variates analysis suggests greater differences between modern humans and the fossil samples than within the fossil samples, and classifies the Xujiayao teeth among modern humans. The present study further clarifies variation of perikymata distribution patterns within the genus Homo. The perikymata distribution of the Xujiayao juvenile tends to be more similar to that of modern humans than to either early Homo or Neandertals.