Figure 4.

Documentation of the variation of plantar aponeurosis form among humans and other primates and classification of primate locomotor behaviour. The absence (white dot) or presence (black or grey dot) of three key characters was documented: plantaris muscle (I) as well as lateral (II) and central (III) band of a plantar aponeurosis. Two categories were used to classify primates’ locomotor behaviour. The first category indicates primates that have feet primarily adapted for suspensory (black dot with S), vs. propulsive (white dot with P). The second category indicates primates that spend significant amounts of time in terrestrial (black dot with T) vs. arboreal locomotion (white dot with A). To understand the evolutionary pattern that preceded humans the plantar aponeurosis form was analysed at each of the following major nodes (black numbered dots), representing last common ancestors of: all primates (1), all haplorhines (2), all catarrhines (3), all apes (4), great apes (5), African apes (6), and Pan/Homo (7).