Dental Morphometric Variation Between African and Asian Colobines, With Special Reference to the Other Old World Monkeys Ruliang Pan* School of Anatomical Sciences, University of Witwatersrand, Johannesburg, Parktown, Johannesburg 2193, South Africa ABSTRACT In order to reveal differences between Asian and African colobines (nonhuman primates) in terms of dietary adaptation and evolutionary develop- ment, a large number of the species of the cercopithecoids (Old World monkeys) was analyzed with morphometric methods. In addition to the raw data and ratios, devia- tions of the colobines, predicted from allometric baselines derived from the cercopithecines, were analyzed by uni- variate and multivariate analyses. Some results indicated that there exists significant differentiation between colo- bines and cercopithecines; the latter exhibit a larger den- tal scale relative to body size, and the less developed front teeth of the colobines may be related to their fewer fre- quent incisal use, compared with those of the cerco- pithecines. With regard to variations between the two subtribes of the colobines, which are found in African (Colobina) and Asia (Presbytina), the Asian subtribe dis- plays a larger scale of postcanine teeth, referring to the results of the raw data. This may correspond to their larger body size. While ratios were considered, the varia- tion between Presbytina and Colobina was diminished greatly. This implies that, unlike the scenario postulated to reflect the relationships between colobines and cercopithecines—which supposes that their differentia- tion is in both size and shape—the variation between the two subtribes is principally size associated: relative to body size Colobina exhibits more emphasized incisors, but less developed postcanine teeth—with the exception of width of M3s. In other words, the relationships between teeth and body size of the African colobines are more similar to those of the cercopithecines. This implies, com- pared to their Asian partners, that African colobines share more similarities with cercopithecines. This may be re- lated to the episodes in which African species underwent a longer period of sharing environmental and climatic pat- terns with the cercopithecines that moved to Asia about 5 or 8 million years ago. Canines were found to be important in distinguishing colobines from cercopithecines and in separating one subtribe from the other. J. Morphol. 267: 1087–1098, 2006. © 2006 Wiley-Liss, Inc. KEY WORDS: colobines; Africa; Asia; Colobina; Presby- tina; cercopithecines; dental morphometric variation; di- etary adaptation; evolution Colobines are primates now widely distributed in Asia and Africa. The great diversities among them in many aspects have made it difficult to understand their biological issues clearly, and thus the relation- ships between taxa (genera, species, and subspecies) and their systematic position among Old World monkeys still remain difficult to determine. This is more impressive if the historical alternations re- garding their classification and phylogeny are re- viewed: they were once regarded as an independent family, Colobidae (Ye et al., 1987; Groves, 1989); a subfamily, Colobinae, in Cercopithecidae (Corbet and Hill, 1987; Fleagle, 1988; Groves, 2001); and one family that contained two subfamilies, Nasalinae and Colobinae (Groves, 1989). They were also re- garded as two groups, or subtribes, in a subfamily— the Presbytina including Asian species and the Colo- bina containing African taxa (Strasser and Delson, 1987; Delson, 1994). Thus, more studies to clarify those controversies from different fields are ex- tremely necessary. Colobines now inhabit the forests and the wood- lands of African tropical regions and southern and eastern Asia. They are now found in habitats around the equator—the forest gallery by the Nile River (Colobus guereza) in Africa and the coastal swamp forests in Asia (Nasalis larvatus) (Rowe, 1996); con- fined to the plateaus—the Qinghai–Tibet Plateau— adjacent to the Himalayas, where, in a habitat cov- ered by snow all year round and with dominant coniferous forest and lichen, one of the snub-nosed monkey species (Rhinopithecus bieti) is found. The niches occupied by this species reach an altitude of 4,700 m above sea level (Li et al., 1981, 2002). Although colobines are generally regarded as fo- livorous primates—feeding primarily on leaves, Contract grant sponsors: Paleontology Scientific Trust; the Na- tional Research Foundation, South Africa. *Correspondence to: Dr. Ruliang Pan, School of Anatomical Sci- ences, University of Witwatersrand, Johannesburg, 7 York Rd., Park- town, Johannesburg 2193, South Africa. E-mail: ruliang.pan@wits.ac.za Published online 2 June 2006 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/jmor.10463 JOURNAL OF MORPHOLOGY 267:1087–1098 (2006) © 2006 WILEY-LISS, INC.