Connecting morphology, function and tooth wear in microchiropterans

Abstract

A key objective in understanding the dentition of mammals is the ability to predict the function of teeth from their shape. Very few studies have used dental measurements that allow the prediction of comparative tooth effectiveness, particularly when modification in shape due to tooth wear is considered. Here, dental parameters are used in which a change in the parameter is readily interpretable in terms of change in factors such as increased force or energy required for cusps or crests to break down food. The functional parameters were measured for 3-D digital tooth reconstructions of the upper molars of the microchiropteran Chalinolobus gouldii at various stages of tooth wear. The changes in the majority of the parameters, such as decreased tip, edge and cusp sharpnesses, cusp occlusion relief, rake angle and fragment clearance, predict a deterioration in efficacy with increased wear. This conclusion has not been possible with alternative approaches; for instance, there was no significant change in crest length with wear, and so no change in function would be predicted from that measure. Some of the parameters did not change significantly with heavy wear, such as capture area of a crest, pointing to geometrical and design characteristics for the maintenance of shape with wear in the dilambdodont tooth form. Attrition and abrasion can be considered as wear on the relief and rake surfaces of tribosphenic-like crests, respectively. The differences in function of these two surfaces account for the differences in wear patterns. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 81–96.