Variation in tooth morphology of Pongo pygmaeus.

This study examines the postcanine morphology of Pongo pygmaeus, identifying sexual, populational, and subspecific differences, with particular focus on the cusp area proportions. Little differences between the sexes were found in molar shapes, and cusp area proportions can be considered population specific. Inter-population differences are significant between the two Bornean populations, with the Kapuas River as a biogeographic barrier, and are as great as inter-subspecies (Borneo-Sumatra) differences.