Anthropological Institute and Museum, University of Zurich, Switzerland
Saturday All day, Plaza Level
In the past, the fibula has been overlooked in comparative studies due to the scarce chance of preservation of a thin bone and the poor involvement in supporting the weight of the human body. However, the fibula serves as an important origin for some muscles of the lower leg.
The aim of this study was to look for differences in the origin and insertion of m. peroneus longus which can provide new insights into the degeneration of the great toe in humans and orangutans during evolution. This is especially interesting since there is still an ongoing debate if australopithecines and early Homo possessed human-like feet with adducted great toes or ape-like feet with opposable halluces.
Fibulae of chimpanzees, orangutans, macaques and modern humans were morphologically compared to the fossilized fibular fragments of Stw 356 (Au.africanus) and OH 35 (H.habilis). Dissections of the lower leg and foot of the previously mentioned primates were performed to obtain precise information about the origin, insertion and function of the muscles with special attention given to muscles with insertions upon the hallux.
The obtained results indicate that the studied fossils morphologically show a more human-like pattern. No significant differences concerning the origin, insertion, gross morphology and weight proportion of m. peroneus longus in the ape specimen were recognizable. The single exception is that the insertion of m. peroneus longus differs in humans.