The most striking feature of the dentition of Zinjanthropus is the enormous size of the premolars and molars. All of the cheek-teeth are significantly greater even than those of the crassident South African australopithecine, Paranthropus, and, in some dimensions, a few of the teeth approach and even surpass some of the Gigantopithecus teeth of China. In Table 29, the dimensions of each of the sixteen teeth of Zinjanthropus are given.

Notes on methodology and terminology

In this account, we have used the term mesiodistal crown diameter (or simply m.d.) in preference to the term ‘length’, for some workers (e.g. Olivier, 1960) have designated this dimension ‘maximum breadth’. In fact, as Moorrees (1957, pp. 79–80) has pointed out, almost as many workers have called this measure crown breadth as have called it crown length!

Similarly, we have used the term labiolingual crown diameter (l.l.) for anterior teeth and buccolingual crown diameter (b.l.) for cheek-teeth, instead of ‘breadth’ or ‘maximum thickness’. Where both anterior and cheek-teeth are reflected in a single table (e.g. Table 29), the term buccolingual is preferred.

To measure these two dimensions, a Helios Vernier sliding caliper was used, with points especially sharpened to a fine taper, in order to enable them to be inserted between teeth in a jaw. The instrument was calibrated in millimetres and tenths of millimetres, as well as tenths and hundredths of an inch.