Fig. 2.

The mean contour of the superior margins of the left and right mandibular ramus in A. L. 822-1 compared with the mean contours of other primates. The A. L. 822-1 contour constitutes the border of the shaded area. Note that the contours fall into two distinct groups. Each contour was plotted with the posterior margin of the ramus vertically oriented. The tip of each condylar process lies at the upper left corner of the coordinate system (the zero point), and the anterior margin of the ramus lies at the far right, at the vertical line T. These contours do not express the posteriorly directed tip of the coronoid process (see Fig. 1) exhibited by A. L. 822-1 and many gorillas; the resolution of the grid does not capture the full extent of the tip's morphology.