Extended Data Fig. 9: Bone tool from Shiyu.
From: Initial Upper Palaeolithic material culture by 45,000 years ago at Shiyu in northern China
a–c, Photograph, 3D model and drawing of different aspects of a bone tool shaped by knapping. Patterns in c identify flake scars (I), spiral fracture (II), unmodified cortical bone (III), and (IV) limits between these areas. Scale = 1 cm. d, Correlation between the length of Shiyu diaphyesal fragments bearing spiral fractures and the number of flake scars occurring on them compared with the artefact interpreted as bone tool highlights the object stands out for its small size and very large number of flake scars. e, Perspective rendering of the bone tool showing the segmented vascular canals (red). f, g, The two planes correspond to the transverse section (red: f) and the longitudinal section (green: g) of the bone tool. Most of the vascular canals are longitudinally oriented as shown by their circularity when viewed in cross section. Radial anastomoses can be observed in the two sections and appear elongated in transverse section (f) and round in the longitudinal plane (g) (white arrows). The longitudinal vascular canals are organized in circular row and circumferential lamellae are discernible in the subperiosteal region (below the red dotted line in f). Secondary osteons delimited by a cement line are scarce and in less mineralized areas (f and g, arrowheads). The CT images also reveal the presence of diagenetic alteration such as microcracks and inclusion of denser (brighter) particles lying mainly inside the bone empty spaces, namely the vascular canals (blue arrows).
