Size and shape of the mandibular condyle in primates
Version of Record online: 6 FEB 2005
Copyright © 1983 Wiley-Liss, Inc.
Journal of Morphology
Volume 177, Issue 1, pages 59–68, July 1983
How to Cite
Smith, R. J., Petersen, C. E. and Gipe, D. P. (1983), Size and shape of the mandibular condyle in primates. J. Morphol., 177: 59–68. doi: 10.1002/jmor.1051770106
- Issue online: 6 FEB 2005
- Version of Record online: 6 FEB 2005
The relationships between the size of the articular surface of the mandibular condyle and masticatory muscle size, tooth size, diet, and biomechanical variables associated with mastication were studied by taking 12 measurements on skulls of 253 adult female anthropoid primates, including three to ten specimens from each of 32 species.
In regressions of condylar length, width, or area against body weight, logarithmic transformations substantially improve the fit of the equations compared with untransformed data. There is a strong relationship betwden condylar measurements and body weight, with all correlations being .94 or higher. The slopes of the allometric regressions of length, width, and area of the condylar head indicate slight positive allometry with body size.
Folivorous primates have smaller condyles than frugivorous primates, and colobines have smaller condyles than cebids, cercopithecines, or hominoids. When colobines are eliminated, the differences between frugivores and folivores are not significant. However, the two species with the relatively largest condyles are Pongo pygmaeus and Cercocebus torquatus, suggesting that there may be a relationship between unusually large condylar dimensions and the ability to crak hard nuts between the teeth.
Cranial features having strong positive correlations with condylar dimensions include facial prognathism, maxillary incisor size, maxillar postcanine area, mandibular ramus breadth, and temporal fossa area. These data are interpreted as indicating that relatively large condyles are associated with relatively large masticatory muscles, relatively inefficient mandibular biomechanics, and a large dentition. These relationships support the growing evidence that the temporomandibular joint is a stress-bearing joint in normal function.