Fig 1.
Map showing the location of Sibudu, the floor of the site and the relevant stratigraphy profile covering the Howiesons Poort and post-Howiesons Poort.
Adapted from [41]).
Table 1.
List of taxa identified at Sibudu with cortical bone potentially suitable for tool manufacture.
Data are adapted from [6] and [41]. HP is Howiesons Poort, p-HP is post-Howiesons Poort and MNI is minimum number of individuals.
Fig 2.
Bone tool manufacturing processes.
1) First the epiphyses are removed and then 2) the shaft is quartered by carving grooves down the length of the shaft and hammering a wedge into the groove. 3) Finally, the blank is whittled or ground into shape using a sharp lithic blade or abrasive stone surface. 4) The diameter of the end product will usually contain a representative portion of cortical bone, perhaps missing only the extreme endosteal and periosteal surfaces.
Fig 3.
Comparison between primary and secondary bone tissue.
The top row are typical histological thin section micrographs, while the images in the bottom row are derived from micro-CT And are taken from [22].
Fig 4.
Graph showing how osteon dimensions differ between animal taxa.
Table 2.
Quantitative and qualitative characteristics of six mammalian taxa.
Fig 5.
The sub-set of cylindrical bone tool shafts from Sibudu reported on in the paper.
Table 3.
Qualitative and quantitative histological results listing the probable animal taxon identification for each artefact.
Osteon measurements are for secondary osteons only.
Fig 6.
Some comparative CT-rendered histologic slices through cortical humerus bone from: A) primate, B) canid, C) ostrich, D) felid, and E) giraffe. Each image is orientated with the perisosteal surface on the right.
Fig 7.
Examples of CT-rendered bone histographies from Artiodactyla (A, #8 and B, #17), Perissodactyla (C, #10 and D, # 19), primate (E, # 2), and carnivore (F, # 18). Cr indicates heat-induced cracking; DD indicates digenetic dissolution; and HM indicates hyper-mineralisation.
Fig 8.
Notched piece from pre-Still Bay layers (C4a BS14).
Fig 9.
Three-dimensional tomography showing cut marks on shaft #15 (C6d GS).
These cut marks are consistent with arrow retrieval marks identified elsewhere.