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Comparison between the length (a), width (b), and thickness of the compact bone (c) of Swartkrans bone tools and of a representative sample of bone fragments from Swartkrans members 1–3 showing no postdepositional breakage. Arrows in a indicate the length of the complete bone tools. This figure is shown in color in Fig. 9, which is published as supplemental data on the PNAS web site, www.pnas.org.
