Earliest complete hominin fifth metatarsal-Implications for the evolution of the lateral column of the foot.
StW 114/115, from Sterkfontein, South Africa, is the earliest complete hominin fifth metatarsal. Comparisons of StW 114/115 to modern humans, extant apes, and partial hominin metatarsals AL 333-13, AL 333-78, SKX 33380, OH 8, and KNM-ER 803f reveal a similar morphology in all six fossils consistent with habitual bipedality. Although StW 114/115 possesses some primitive characters, the proximal articular morphology and internal torsion of the head are very human-like, suggesting a stable lateral column and the likely presence of lateral longitudinal and transverse tarsal arches. We conclude that, at least in the lateral component of the foot of the StW 114/115 individual, the biomechanical pattern is very similar to that of modern humans. This, however, may not have been the case in the medial column of the foot, as a mosaic pattern of hominin foot evolution and function has been suggested. The results of this study may support the hypothesis of an increased calcaneo-cuboid stability having been an early evolutionary event in the history of terrestrial bipedalism.
Zipfel
Bernhard
B
Bernard Price Institute for Palaeontological Research, School of Geosciences, University of the Witwatersrand, PO Wits, 2050 Wits, South Africa. bernhard.zipfel@wits.ac.za
DeSilva
Jeremy M
JM
Kidd
Robert S
RS
D000717:Anatomy, Comparative; D000818:Animals; D005075:Biological Evolution; D005260:Female; D005528:Foot / Q000033:anatomy & histology*; D005580:Fossils; D015186:Hominidae / Q000033:anatomy & histology*; D006801:Humans; D008124:Locomotion / Q000502:physiology; D008297:Male; D008682:Metatarsal Bones / Q000033:anatomy & histology*; D015999:Multivariate Analysis