Department of Anthropology, University of California, Santa Cruz
Friday All day, Plaza Level
Standardized methods of dissection contribute to developing a comparative database for understanding primate adaptation and evolution. In this poster we visually represent how we partition the individual into its dissectible body segments on one side of the body and analyze them relative to total body mass (TBM). On the other side, individual muscle weights are analyzed according to functional groups. To illustrate our dissections and methods we highlight with three comparisons: segment masses between infant, juvenile, and adult gibbons of the same sex and species but of different body masses (Hoolock leucoedys); muscle groups between infant and adult gibbons; and limb proportions between monkey and ape (Macaca and Hoolock). Juvenile gibbon limb segments are relatively heavier than either infant or adult (infant forelimbs: 16.8% (TBM), hindlimbs 15.6%; juvenile forelimbs, 20%, hindlimbs, 21%; adult 16.5%, 16.0% respectively). Hands and feet are heaviest in the infant (hands, 26.7% of limb segment mass; feet, 23.8%), lightest in the adult (14.3%, 15.1%). In musculature, the gibbon infant has relatively heavier elbow, wrist and digital extensors than the adult. The infant gibbon contrasts with infant macaques in limb proportions, whose forelimbs are 11% TBM, hind limbs 15.8%, and tail, 1.1%. These methods allow comparisons of equivalent anatomical elements between individuals and are a basis for generating hypotheses about 1) life stage adaptations, e.g., infants have muscular hands and feet for grasping; 2) species-specific locomotor adaptations, e.g. quadrupedal monkey vs suspensory ape, and 3) evolutionary change across taxa through modification of growth patterns.