1Laboratory for the Comparative Study of Morphology, Mechanics and Molecules, Department of Kinesiology, The Pennsylvania State University, 2Biological Anthropology and Comparative Anatomy Research Unit, University of Adelaide
Saturday 11:45-12:00, Grand Ballroom II
Continuing restricted specimen access yielded a limitedly descriptive but richly imaginative study of the LB1 foot (2009) including two statements about limb segment proportions: “the foot of LB1 is very long relative to the femur and tibia” and “the relatively high foot-to-femur ratio…is driven primarily by an exceptionally short hindlimb.” Seemingly transitive, these statements have contrasting functional and developmental implications demonstrable by escaping within-limb constraints through comparisons beyond foot to femur or hind limb alone.
Estimated fleshy foot length of LB1 is 196 mm (95% prediction interval 189-204 mm). Reportedly “[T]he relative foot length in LB1 far exceeds the upper limits for modern humans of either average or short stature.” However, LB1 absolute foot length is only marginally below the minimum (207.5 mm) in a sample of 1905 USAF women (Clauser, et al., 1972) permitting extensive bivariate comparisons. Stature predicted by regression equation from foot length is not 1.06 m but 1.46 m, supported by numerous limb segment comparisons, based on anthropometrics (Clauser, et al., 1972) or osteometrics (Sjøvold, 1990) using bone lengths of LB1. Including the LB1 femur biases stature estimates downward by 7 to >20 cm; Eckhardt, et al. (2005) previously showed that Asian population regressions including LB1 femur length reduced estimated stature by >5 cm. The LB1 foot, while abnormal in various salient ways reflecting compromised locomotion, is not unusually long; rather, the femur of LB1 is abnormally short. Positing LB1 skeletal features as ancient primitive retentions requires not stasis of evolutionary change but suspension of disbelief.