Morphometrics of the anterior dentition in strepsirhine primates.

Size variations in the anterior dentition were analyzed for 26 species of strepsirhine primates. The upper and lower incisor rows of strepsirhines, like those of anthropoid primates, scale isometrically with body size. Within the order Primates, strepsirhines exhibit the smallest incisors relative to body size, followed in increasing size by tarsiers, platyrrhines, and catarrhines. If the lateral teeth of the indriid toothcomb are interpreted as incisors and not canines, correlations between mandibular tooth size variables and body weight are maximized. The upper incisors of strepsirhines are extremely small and frequently widely separated, most likely to minimize occlusion with the toothcomb. Species deviations for assorted size variables of the anterior dentition generally fail to reflect functional variations in the use of the anterior teeth; some of the variables, however, do reflect taxonomic differences within the Strepsirhini. Although toothcomb size variations among extant strepsirhines are more readily interpreted in terms of gum feeding and bark scraping than they are in terms of grooming, anterior dental morphology as a whole is more easily explained by a grooming hypothesis when existing models of toothcomb origins are considered.