Olduvai Hominid 8

Olduvai Hominid number 8 (OH 8) is a fossilized foot of an early hominin found in Olduvai Gorge by Louis Leakey in the early 1960s. Subsequent analysis has provoked much thought. Recent analysis (Kidd, O'Higgins & Oxnard, JHE, 1996) has demonstrated quite clearly that the fossil assemblage exhibits both ape and human characteristics. Essentially, the lateral side (i.e. the outside of the foot) contains human-like characteristics while the medial side (i.e. the side towards the midline) contains ape-like features proximally, and human-like features distally. Specifically, the cuboid (laterally) is human-like, the talus and navicular (medially) are ape-like, and the medial cuneiform (medially), is human-like. This may be looked upon as a missing link in terms of mid-tarsal joint function. Later fossil finds, as exemplified by the so-called "Little Foot" (Stw573), do not contradict this - they in fact complement this finding (Kidd & Oxnard 2004).

Stw573 is a medial column assemblage, consisting of a talus, navicular, medial cuneiform and a first metatersal stub. The three hindfood bones present a pattern consistent with those of the OH 8 assemblage. Thus the hypothesis of a divergent first ray in the OH 8 assemblage, proposed in Kidd et al. (1996), is now refuted, and neither fossil assemblage are thought to have this characteristic.

Further work by Zipfel and Kidd (2006) and Zipfel, DeSilva and Kidd, 2009) complement these findings. Moreover, they collectively lead to an intregrative model of pedal evolution of caudo-cranial, disto-proximal changes. Yet further findings (Zipfel et al., 2011), with regard to the recently found skeletal remains of Australopithecus sediba, reinforce the earlier findings. Further they demonstrate that the disto-proximal issues of the medial column, may also present in the lateral column. Combined, these findings refute the "Hypothetical Prehuman Foot", as predicted by Morton in 1935. Specifically, Morton predicted an "atavistic" divergent first ray, and a very substantially developed calcaneus as being present in the first bipeds; neither of these features are supported by current findings.