COMPARISON OF DIAPHYSEAL GROWTH BETWEEN THE LIBBEN POPULATION AND THEHAMANN-TODD CHIMPANZEE SAMPLE

The differences in limb lengths and proportions between humans and chi mpanzees are widely known. Humans have relatively shorter forelimbs an d longer hind limbs than chimpanzees. Humans have a longer period of l ong bone formation than chimpanzees. Recent advances in estimating age -at-death in chimpanzees from their dentition have allowed us to reexa mine long bone growth in chimpanzees using their skeletal remains and compare it with similar data for humans. A chronological normalization procedure allowing direct interspecific comparison of long bone growt h is presented. The preadult chimpanzee sample (n = 43) is from the Ha mann-Todd Osteological Collection from the Cleveland Museum of Natural History. All human specimens (n = 202) are from the late Woodland Lib ben Population currently housed at Kent State University. Relying on t hese cross-sectional data, we conclude that both species elongate thei r femora at similar absolute (length per unit time) but different rela tive (length relative to normalized dental age) rates. The species dif fer in the absolute growth rate of the humerus but share a common norm alized rate of growth. Forelimb segment proportion differences between species are due to differential elongation rates of the segments. Hin d limb diaphyseal proportions are the same in both species, which sugg ests that changes in segment length are proportional. Therefore, alter native developmental mechanisms exist in these closely related species which can produce changes in limb length. (C) 1996 Wiley-Liss, Inc.