Dental Variation Among Asian Colobines, with Specific Reference to the\nMacaques on the Same Continent

In order to discern dental morphometric variations among the Asian\ncolobines, residuals of the colobines, derived from allometric\nbaselines formed by the Asian macaques (Macaca), were analyzed with\nPrincipal Components Analysis and Euclidean Distances. Results\nindicated that the widely accepted view that the colobines possess\nrelatively smaller front teeth than the macaques is only the case for\nthe first incisors. The colobines show relatively smaller molars than\nthe macaques. Such profiles may be related to the differences in\ndietary preferences between the two major groups of the Asian Old World\nmonkeys. The magnitude of such differences is not as great as usullay\nassumed for the two groups that contain both African and Asian taxa. In\nother words, the two Asian cercopithecoid groups may have homogenously\nbeen shaped by the tectonic modifications and climate alterations in\nthe past five million years. There exist marked differences among the\nAsian colobines when each of the genera is compared with macaques; the\ndental profile reflects not only the variation in geographic\ndistribution but also in phylogenetic divergence. Thus, the snub-nosed\nmonkeys (Rhinopithecus) and the gray langurs (Semnopithecus) are\ncharacterized by relatively larger molars than the other colobines\n– larger even than those of the macaques. The differences among\nAsian colobines, depicted by Euclidean Distances, seems to reflect the\nrelationship of the phylogeny and evolution between colobines and\ncercopithecines.