VARIATION IN MOLAR ENAMEL THICKNESS OF THE GENERA "CERCOPITHECUS" AND "COLOBUS"

In the present study, 55 maxillary second molars of six different Colobus- and Cercopithecus-species (C. polykomos, P. badius, P. verus, C. campbelli, C. petaurista, C. diana) were sectioned bucco-lingually through the mesial cusps. Several measures and indices were recorded in order to determine differences in enamel thickness between the species. As has often been postulated without ever having been proven on a sample of considerable size, it has been expected for the predominantly leaf-eating Colobinae to have thinner enamel than the mostly fruit-eating Cercopithecinae. This hypothesis could be confirmed, but only for relative thickness referring to tooth size. Absolutely, most Colobines had generally thicker enamel because of their larger body- and tooth-size, but not P. verus. The relatively thin enamel was related to high cusps and could therefore be interpreted as an adaptation to a folivorous diet. Additionally, the enamel was differently distributed over the crown, for in cercopithecine molars, the enamel was substantially thicker on the lingual than on the buccal side, whereas in colobine teeth, the enamel was more equally distributed. This was interpreted as allowing the cusps to be more uniformally abraded resulting in shearing blades that lay on one level.