Function and Fusion of the Mandibular Symphysis in Primates

Stiffness or Strength?
  • Matthew J. Ravosa
  • William L. Hylander
Part of the Advances in Primatology book series (AIPR)


Over the past. 30 years a series of morphological and experimental analyses have attempted to address questions about the functional and evolutionary significance of mandibular symphyseal fusion or complete ossification of the joint between the two dentaries (Scapino, 1965, 1981; Hylander, 1975a, 1977, 1979a,b, 1984, 1985; Beecher, 1977, 1979, 1983; Hirschfeld et al., 1977; Dessein, 1985; Hylander et al., 1987; Greaves, 1988, 1993; Ravosa, 1991; M. J. Ravosa, unpublished data; Ravosa and Hylander, 1993; Hylander and Johnson, 1994; Ravosa and Simons, 1994). This work has increased our understanding of the functional morphology of the mammalian masticatory apparatus, in part by highlighting the interaction of jaw mechanics, diet and allometry on symphyseal form. Many of these studies have also influenced adaptive explanations for the evolution of anthropoid craniodental morphology and impact directly on hypotheses regarding phylogenetic affinities among certain Eocene and Oligocene primates (Hiiemae and Kay, 1972, 1973; Gingerich, 1977, 1979; Beecher, 1977, 1979; Cachel, 1979a,b; Hylander, 1979a,b; Szalay and Delson, 1979; Rosenberger, 1981, 1986; Rosenberger et al., 1985; Rasmussen, 1986, 1990; Greaves, 1988, 1993; Simons, 1989, 1990, 1992; Ravosa, 1991; M. J. Ravosa, unpublished data; Rasmussen and Simons, 1992; Ravosa and Hylander, 1993; Ravosa and Simons, 1994).


Bite Force Positive Allometry Anthropoid Primate Hard Object Mandibular Symphysis 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Beecher, R. M. 1977. Function and fusion at the mandibular symphysis. Am. J. Phys. Anthrojml. 47:325–336.CrossRefGoogle Scholar
  2. Beecher, R. M. 1979. Functional significance of the mandibular symphysis. J. Morphol. 159:117 – 130.PubMedCrossRefGoogle Scholar
  3. Beecher, R. M. 1983. Evolution of the mandibular symphysis in Notharctinae (Adapidae, Primates). Int. J. Primatoi. 4:99–112.CrossRefGoogle Scholar
  4. Bouvier, M. 1986a. A biomechanical analysis of mandibular scaling in Old World monkeys. Am. J. Phys. Anthropol. 69:473–482.CrossRefGoogle Scholar
  5. Bouvier, M. 1986b. Biomechanical scaling of mandibular dimensions in New World monkeys. Int. J. Primatoi. 7:551–567.CrossRefGoogle Scholar
  6. Bouvier, M., and Hylander, W. L. 1981. Effect of bone strain on cortical bone structure in macaques (Marara mulatto). J. Morphol. 167:1–12.PubMedCrossRefGoogle Scholar
  7. Cachel, S. M. 1979a. A functional analysis of the primate masticatory system and the origin of the anthropoid post-orbital septum. Am. J. Phys. Anthropol. 50:1–18.CrossRefGoogle Scholar
  8. Cachel, S. M. 1979b. A paleoecological model for the origin of higher primates. J. Human Evol. 8:351–359.CrossRefGoogle Scholar
  9. Crompton, A. W., and Hiiemae, K. M. 1970. Molar occlusion and mandibular movements during occlusion in the American opossum, Didelphis marsupialis L. Zool. J. Linn. Soc. 49:21–47.CrossRefGoogle Scholar
  10. Daegling, D.J. 1992. Mandibular morphology and diet in the genus Cebus. Int. J. Primatoi. 13:545–570.CrossRefGoogle Scholar
  11. Dessein, D. 1985. The transmission of muscle force across the unfused symphysis in mammalian carnivores. Fortsein: Zool. 30:289–291.Google Scholar
  12. Fleagle, J. C. 1988. Primate Adaptation und Evolution. Academic Press, New York.Google Scholar
  13. Gingerich, P. D. 1977. Radiation of Eocene Adapidae in Europe. Geobios Mem. 1:165–182.CrossRefGoogle Scholar
  14. Gingerich, P. D. 1979. Phylogeny of middle Eocene Adapidae (Mammalia, Primates) in North America: Smilodectes and Not haretus. J. Paleontol. 53:153–163.Google Scholar
  15. Gingerich, P. D. 1980. Dental and cranial adaptations in Eocene Adapidae. Z. Morphol. Anthropol. 71:135–142.Google Scholar
  16. Greaves, W. S. 1988. A functional consequence of an ossified mandibular symphysis. Am. J. Phys. Anthropol. 77:53–50.PubMedCrossRefGoogle Scholar
  17. Creaves, W. S. 1993. A reply to Drs. Ravosa and Hylander. Am. J. Phys. Anthropol. 90:513–514.CrossRefGoogle Scholar
  18. Iiappel, R. 1988. Seed-eating by West African cercopithecines, with reference to the possible evolution of bilophodont molars. Am. J. Phys. Anthropol. 75:303–327.CrossRefGoogle Scholar
  19. Herring, S. W., and Scapino, R. P. 1973. Physiology of feeding in minature pigs. J. Morphol. 141:427–460.PubMedCrossRefGoogle Scholar
  20. Hiiemae, K. M., and Crompton, A. W. 1985. Mastication, food transport, and swallowing. In: M. Hildebrand, D. M. Bramble, K. E. Eiem, and D. B. Wake (eds.), Functional Vertebrate Morphology, pp. 262–290. Harvard University Press, Cambridge.Google Scholar
  21. Hiiemae, K. M., and Kay, R. E. 1972. Trends in the evolution of primate mastication. Nature 240:486–487.CrossRefGoogle Scholar
  22. Hiiemae, K. M., and Kay, R. E. 1973. Evolutionary trends in the dynamics of primate mastication. In: M. R. Zingeser (ed.), Symposia of the Fourth International Congress of Primatology, Vol. 3: Craniofacial Biology of Primates, pp. 28–64. S. Karger, Basel.Google Scholar
  23. Hirschfeld, Z., Michaeli, Y., and Wienreb, M. M. 1977. Symphysis menti of the rabbit: Anatomy, histology, and postnatal development. J. Dent. Res. 56:850–857.PubMedCrossRefGoogle Scholar
  24. Hylander, W. E. 1975a. Ehe human mandible: Lever or link? Am. J. Phys. Anthropol. 43:227–242.PubMedCrossRefGoogle Scholar
  25. Hylander, W. L. 1975b. Incisor size and diet in anthropoids with special reference to Cer- copithecidae. Science 189:1095–1098.PubMedCrossRefGoogle Scholar
  26. Hylander, W. L. 1977. In vivo bone strain in the mandible of Galago crassicaudatus. Am. J. Phys. Anthropol. 46:309–326.PubMedCrossRefGoogle Scholar
  27. Hylander, W. L. 1979a. Mandibular function in Galago crassicaudatus and Macaca fascicularis: An in vivo approach to stress analysis of the mandible. J. Morphol. 159:253–296.PubMedCrossRefGoogle Scholar
  28. Hylander, W. L. 1979b. Ehe functional significance of primate mandibular form. J. Morphol. 160:223–240.PubMedCrossRefGoogle Scholar
  29. Hylander, W. L. 1984. Stress and strain in the mandibular symphysis of primates: A test of competing hypotheses. Am. J. Phys. Anthropol. 64:1–46.PubMedCrossRefGoogle Scholar
  30. Hylander, W. L. 1985. Mandibular function and biomechanical stress and scaling. Am. Zool. 25:315–330.Google Scholar
  31. Hylander, W. L. 1988. Implications of m vivo experiments for interpreting the functional signifi cance of “robust” australopithecine jaws. In: F. E. Grine (ed.), Evolutionary History of the “Robust” Australopithecines, pp. 55–83. Aldine de Gruyter, New York.Google Scholar
  32. Hylander, W. L., and Johnson, K. R. 1994. [aw muscle function and wishboning of the mandible during mastication in macaques and baboons. Am. J. Phys. Anthropol. 94: 523–547.PubMedCrossRefGoogle Scholar
  33. Hylander, W. L., Johnson, K. R., and Grompton, A. W. 1987. Loading patterns and jaw movements during mastication in Macaco, fascicularis: A bone-strain, electromyographic and cin- eradiographic analysis. Am. J. Phys. Anthropol. 72:287–314.PubMedCrossRefGoogle Scholar
  34. Hylander, W. L., Johnson, K. R., and Grompton, A. W. 1992. Muscle force recruitment and biomechanical modeling: An analysis of masseter muscle function during mastication in Macaca fascicularis. Am. J. Phys. Anthropol. 88:365–387.PubMedCrossRefGoogle Scholar
  35. Jolly, G. J. 1970. Hadropithecus, a lemuroid small object feeder. Man 5:525–529.CrossRefGoogle Scholar
  36. Kallen, F. G., and Gans, G. 1972. Mastication in the little brown bat, Myotis lucifugus. J. Morphol. 136:385–420.CrossRefGoogle Scholar
  37. Rasmussen, D. T. 1986. Anthropoid origins: a possible solution to the Adapidae—Omomyidae paradox. J. Hum. Evol. 15:1–12.CrossRefGoogle Scholar
  38. Rasmussen, D. T. 1990. The phylogenetic position of Mahgarita stevensi: Protoanthropoid or lemuroid? Int. J. Primatol. 11:439–469.CrossRefGoogle Scholar
  39. Rasmussen, D. T., and Simons, E. L. 1992. Paleobiology of the oligopithecines, the earliest known anthropoid primates. Int. J. Primatol. 13:477–508.CrossRefGoogle Scholar
  40. Ravosa, M. J. 1991. Structural allometry of the mandibular corpus and symphysis in prosimian primates. J. Hum. Evol. 20:3–20.CrossRefGoogle Scholar
  41. Ravosa, M.J., and Hylander, W. L. 1993. Functional significance of an ossified mandibular symphysis: A reply. Am. J. Phys. Anthropol. 90:509–512.PubMedCrossRefGoogle Scholar
  42. Ravosa, M. J., and Simons, E. L. 1994. Mandibular growth and function in Archaeolemur. Am. J. Phys. Anthropol. (in press).Google Scholar
  43. Richard, A. F. 1985. Primates in Nature. W. H. Freeman, New York.Google Scholar
  44. Rosenberger, A. L. 1981. A mandible olBranisella boliviano (Platyrrhini, Primates) from the Oligocene of South America. Int. J. Primatol. 2:1–7.CrossRefGoogle Scholar
  45. Rosenberger, A. L. 1986. Platyrrhines, catarrhines and the anthropoid transition. In: B. A. Wood, L. Martin, and P. Andrews (eds.), Major Topics in Primate and Human Evolution, pp. 66–88. (Cambridge University Press, Gambridge.Google Scholar
  46. Rosenberger, A. L., Strasser, E., and Delson, E. 1985. Anterior dentition of Notharctus and the adapid-anthropoid hypothesis. Fol. Primatol. 44:15–39.CrossRefGoogle Scholar
  47. Scapino, R. P. 1965. The third joint of the canine jaw. J. Morphol. 116:23–50.PubMedCrossRefGoogle Scholar
  48. Scapino, R. P. 1981. Morphological investigation into functions of the jaw symphysis in carni- vorans. J. Morphol. 167:339–375.PubMedCrossRefGoogle Scholar
  49. Simons, E. L. 1989. Description of two genera and species of Late Eocene Anthropoidea from Egypt. Proc. Natl. Acad. Sci. USA 86:9956–9960.PubMedCrossRefGoogle Scholar
  50. Simons, E. L. 1990. Discovery of the oldest known anthropoidean skull from the Paleogene of Egypt. Science 247:1567–1569.PubMedCrossRefGoogle Scholar
  51. Simons, E. L. 1992. Diversity in the early Tertiary anthropoidean radiation in Africa. Proc. Natl. Acad. Sci. USA 89:10743–10747.PubMedCrossRefGoogle Scholar
  52. Szalay, F. S., and Delson, E. 1979. Evolutionary History of the Primates. Academic Press, New York.Google Scholar
  53. Tattersall, I. 1982. The Primates of Madagascar. Golumbia University Press, New York.Google Scholar
  54. Zingeser, M. R. 1976. Arch form, tooth size, and occlusomandibular kinesis in the Geboidea. Am. J. Phys. Anthropol, 45:317–330.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • Matthew J. Ravosa
    • 1
    • 2
  • William L. Hylander
    • 1
  1. 1.Department of Biological Anthropology and AnatomyDuke University Medical CenterDurhamUSA
  2. 2.Department of Zoology, Division of MammalsField Museum of Natural HistoryChicagoUSA

Personalised recommendations