Fig. 1.

(A) 3D scan images, from left to right, in radial (Upper) and dorsal view (Lower) of third metacarpals of a common chimpanzee, Australopithecus afarensis (A.L. 438-1d), Australopithecus sediba (MH 2), a Neandertal (Shanidar 4), and a modern human (USNM 380447). All are shown as from the right hand and scaled to approximately the same articular length. Note the distinctive styloid process (black arrows) is present only in the modern human and Neandertal specimens. (B) Photograph of KNM-WT 51260 in radial, ulnar, dorsal, and volar views (Left) and proximal and distal views (Right). Note the presence of a distinctly human-like styloid process.