5 - Relationships between the Diet and Dentition of Asian Leaf Monkeys

Summary

Although the Colobinae were initially described as dentally homogenous, accumulating ecological evidence suggests great dietary diversity, which in turn predicts dental diversity within this speciose subfamily. In this study, we test hypotheses concerning dental function based on variation in food and food physical properties among Asian genera. We test whether those taxa that destroy seeds during ingestion have relatively narrow incisor rows, whether species that consume more seeds have less molar cresting and more wedge-shaped cusps, and whether those species exhibiting the lowest intake of leaves have larger, more bunodont molars. Among seven genera, the seed-consuming Presbytis has the smallest teeth with the highest cusps; contra our predictions, they also have relatively wide incisors and the most crested molars. Rhinopithecus, which has a varied diet defined by petiole, leaf, lichen and fruit consumption, has wide incisor rows and the largest and shortest molars. The patterns found for the other five genera are discussed in light of their respective diets. Even with limited data, it is apparent that Asian colobines are not dentally homogeneous. Furthermore, all of the variables related to the ingestion and digestion of plant foods are combined in different measure in complex ways.