PERMANENT TOOTH CALCIFICATION IN CHIMPANZEES (PAN-TROGLODYTES) - PATTERNS AND POLYMORPHISMS

Tooth calcification is an important developmental marker for use in co nstructing models for early hominid life history, particularly for its application to the fossil record. As chimpanzees are commonly utilize d in interspecific comparisons in such research, this study aims to im prove available baseline data for tooth calcification patterns in chim panzees (Pan troglodytes), and to quantify basic patterns and polymorp hisms. We present an analysis of developmental patterns for the left m andibular dentition (I-1-M(3)) based on intraoral radiographs obtained from a cross-sectional sample of chimpanzees (58 males, 60 females) h oused at LEMSIP (NYU Medical Center) and Yerkes (Emory University). No significant differences with previous descriptions of the basic seque nces of tooth calcification in chimpanzees were found, but variation i n such patterns was documented for the first time. In the overall sequ ence, polymorphisms between the canine and the group (M(2) P-4 P-3) re ached significant levels. This is due to the relative delay in canine crown formation compared to other teeth. Differences in the basic sequ ence between males and females were recorded, but are due to minor shi fts in the percentages of occurrence for polymorphic sequences which a re common to both genders. Perhaps our most important findings are tha t a) different polymorphic sequences occur in tooth calcification and tooth emergence in chimpanzees, and b) developmental relationships amo ng teeth fluctuate throughout tooth calcification. Thus, characterizat ions of dental developmental patterns based on particular stages of de velopment cannot necessarily be extrapolated to other stages without s upporting data. (C) 1996 Wiley-Liss, Inc.