We add some cautionary notes about using the dental data, those presented here or any others, especially but not only when there are comparisons of apes and some australopithecines and humans. Wolpoff (1971), White (1977), Frayer (1978) and others define how MD and BL (or LL) are taken. But these are often not homologous between authors, even sometimes for the same author. There are many examples, but really just two main sources of problems with homology.

(1)The first is in (or between) samples of teeth measures in situ and measurements taken on isolated teeth. The problem here could come for any teeth, but especially for asymmetric ones such as upper molars, lower P3 and canines of both jaws.

(2)The second comes from the fundamentally different shapes of the lower P3 and canines of both jaws, comparing apes and some australopithecines with other hominids. These dimensions are poorly defined and while some authors (cf White) are quite clear about how the measurements can be defined to allow homology, most authors are not. An excellent example is in the argument about the identification and shape of a molar tooth from Bed I, Olduvai. Leakey, Von Koenigswald, Robinson and Dahlberg could not decide whether it was an upper or lower deciduous M2, or a permanent molar tooth, longer than broad or broader than long. This went on in Nature for several years and was never resolved. Comparing data sets invariably have homology issues like this, they are rarely brought to light.