DENTAL DEVELOPMENT IN CHIMPANZEES (PAN-TROGLODYTES) - THE TIMING OF TOOTH CALCIFICATION STAGES

Data are presented documenting the timing of tooth calcification for t he left mandibular dentition (I-1-M(3)) based on a cross-sectional ser ies of intraoral dental X-rays from a sample of 118 captive chimpanzee s. Mean, median, and midpoint ages of attainment; standard deviations (SD); interquartile ranges (IQR); and age ranges were calculated for t he eight developmental stages of these teeth. Minor differences with p revious studies of chimpanzee dental development were found (Anemone e t al. [1991] Am. J. Phys. Anthropol. 86:229-241; Anemone and Watts [19 92] J. Hum, Evol. 22:149-153), but the similarities with previous stud ies are more striking despite the differences in samples. In contrast to other pongid studies, sex differences in developmental timing were documented, particularly for the canine. Regression models for age est imation from dental maturity scores were also presented. This chimpanz ee standard is compared with human standards to determine absolute and relative differences in the timing of crown and root calcification. T he overall period of canine development in both species is nearly iden tical, although those for crown and root formation are markedly differ ent-making this tooth the most distinctive feature between chimpanzee and human dental development periods. Although the molars demonstrate differences in the timing of crown and root calcification periods, the y are more proportional than for other teeth. This contributes to the difficulties in distinguishing between ''human'' and ''chimpanzee'' pa tterns of molar development. The developmental differences discussed a re placed in perspective with consideration to microstructural and mor phological features of chimpanzee and human teeth, and to overall grow th periods in these species. (C) 1996 Wiley-Liss, Inc.