Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-03T00:57:44.617Z Has data issue: false hasContentIssue false
  • English
  • Français

Early chewing mechanisms in mammalian herbivores

Published online by Cambridge University Press:  08 April 2016

John M. Rensberger
John M. Rensberger*
Affiliation:
Department of Geological Sciences and Burke Memorial Washington State Museum DB-10, University of Washington, Seattle, Washington 98195
Get access Rights & Permissions [Opens in a new window]

Abstract

A comparison of the morphology and wear of the chewing surfaces among archaic Paleocene herbivores suggests that a compressive type of interaction between opposing chewing surfaces was becoming a dominant mode of chewing, unlike the translative (grinding or shearing) mechanisms common in Eocene and later herbivores. In part, the evidence for this conclusion is that most of the wear occurs on horizontal surfaces centered at the tips of the cusps and pronounced unidirectional striae tend to be lacking in these areas. In the diverse early Paleocene periptychid condylarths, multidirectional striae occur on the wear surfaces and there is a measured loss of directionality of the crests and enamel edges from the condition in the earliest condylarth, the Late Cretaceous Protungulatum. The patterns are even more random in the later Paleocene phenacodontids, suggesting that this was a broad characteristic for the larger Paleocene condylarths.

Efficiency (that is, the volume of food processed per stroke) in compressional chewing systems is theoretically proportional to the area of the opposing surfaces, with large, relatively flat surfaces optimal, whereas in translational systems linear structures are dominant. The reduction in alignment of striae and in linearity of topographic features of the chewing surfaces is consistent with an increasing dominance of compressive chewing from the condition characteristic of palaeoryctid and probably other Cretaceous insectivores in which both compression and shearing occurred between opposing surfaces. The change was brought about by expanding surface areas at the expense of edge length, which was accomplished independently and differently by the phenacodontids and the periptychids, one by increasing both the cylindrical shape and size of the cusps, the other by increasing the cylindrical shape and converging the cusps. The retention of large paraconules and metaconules in the upper molars, cusps essentially lost in the periptychids, preadapted the phenacodontid pattern for later development of the oblique lophodonty and translatory chewing component characteristic of perissodactyls (horses and their relatives), the dominant herbivores of the Eocene.

Type
Articles
Information
Paleobiology , Volume 12 , Issue 4 , Fall 1986 , pp. 474 - 494
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Literature Cited

Ahlgren, J. 1966. Mechanisms of mastication. Acta Odont. Scand. 24. (suppl. 44):5–109.Google Scholar
Archibald, J. D. 1982. A study of Mammalia and geology across the Cretaceous-Tertiary boundary in Garfield County, Montana: Univ. Calif. Publ. Geol. Sci. 122:1–288.Google Scholar
Atkinson, H. F. and Shepherd, R. W. 1961. Temperomandibular joint distribution and the associated masticatory patterns. Aust. Dent. J. 6:219–222.Google Scholar
Butler, P. M. 1952. The milk-molars of Perissodactyla, with remarks on molar occlusion. Proc. Zool. Soc. Lond. 121:777–817.Google Scholar
Costa, R. L. Jr. and Greaves, W. S. 1981. Experimentally produced tooth wear facets and the direction of jaw motion. J. Paleontol. 55:635–638.Google Scholar
Crompton, A. W. and Hiiemae, K. M. 1970. Molar occlusion and mandibular movements during occlusion in the American oppossum, Didelphis marsupialis. J. Linn. Soc. (Zool.) 49:21–47.Google Scholar
Crompton, A. W. and Kielan-Jaworowska, Z. 1978. Molar structure and occlusion in Cretaceous therian mammals. Pp. 249–287. In: Butler, P. M. and Joysey, K. A., eds. Development, Function and Evolution of Teeth. Academic Press; London.Google Scholar
Greaves, W. S. 1973. The inference of jaw motion from tooth wear facets. J. Paleontol. 47:1000–1001.Google Scholar
Hiiemae, K. M. 1978. Mammalian mastication: a review of the activity of the jaw muscles and the movements they produce in chewing. Pp. 359–398. In: Butler, P. M. and Joysey, K. A., eds. Development, Function and Evolution of Teeth. Academic Press; London.Google Scholar
Hiiemae, K. M. and Kay, R. F. 1973. Evolutionary trends in the dynamics of primate mastication. Pp. 3: 28–64. In: Zingeser, M. R., ed. Craniofacial Biology of Primates. Symp. 4th Int. Cong. Primatol. Karger; Basel.Google Scholar
Hiiemae, K. M. and Thexton, A. J. 1975. Consistency and bite size as regulators of mastication in cats. Abstr. J. Dent. Res. 54(A):194.Google Scholar
Hylander, W. L. 1975. Incisor size and diet in anthropoids with special reference to Cercopithecidae. Science 189:1095–1098.Google Scholar
Hylander, W. L. and Johnson, K. R. 1985. Temporalis and masseter muscle function during incision in macaques and humans. Int. J. Primatol. 6:289–322.CrossRefGoogle Scholar
Kay, R. F. 1978. Molar structure and diet in extant Cercopithecidae. Pp. 309–339. In: Butler, P. M. and Joysey, K. A., eds. Development, Function and Evolution of Teeth. Academic Press; London.Google Scholar
Kay, R. F. and Hiiemae, K. M. 1974. Jaw movement and tooth use in Recent and fossil Primates. Am. J. Phys. Anthropol. 40:227–256.Google Scholar
Koenigswald, W. v. 1980. Schmelzstruktur und Morphologie in den Molaren der Arvicolidae (Rodentia). Abh. Senckenb. Naturforsch. Ges. 539:1–129.Google Scholar
Krause, D. W. 1982. Jaw movement, dental function, and diet in the Paleocene multituberculate Ptilodus. Paleobiology. 8:265–281.Google Scholar
Lucas, P. W. 1979. The dental-dietary adaptations of mammals. N. Jb. Geol. Paläont. Mh. 8:486–512.Google Scholar
Luschei, E. S. and Goodwin, G. M. 1974. Patterns of mandibular movement and jaw muscle activity during mastication in the monkey. J. Neurophysiol. 37:954–966.Google Scholar
Mills, J. R. E. 1955. Ideal dental occlusion in the Primates. Dent. Pract. Bristol. 6:47–61.Google Scholar
Rensberger, J. M. 1973. An occlusal model for mastication and dental wear in herbivorous mammals. J. Paleontol. 47:515–528.Google Scholar
Rensberger, J. M. 1975. Function in the cheek tooth evolution of some hypsodont geomyoid rodents. J. Paleontol. 49:10–22.Google Scholar
Rensberger, J. M. 1978. Scanning electron microscopy of wear and occlusal events in some small herbivores. Pp. 415–438. In: Butler, P. M. and Joysey, K. A., eds. Development, Function and Evolution of Teeth. Academic Press; London.Google Scholar
Rensberger, J. M., Forstén, A., and Fortelius, M. 1984. Functional evolution of the cheek tooth pattern and chewing direction in Tertiary horses. Paleobiology. 10:439–452.Google Scholar
Rensberger, J. M. and Koenigswald, W. v. 1980. Functional and phylogenetic interpretation of enamel microstructure in rhinoceroses. Paleobiology. 6:477–495.Google Scholar
Rose, K. D. 1981. The Clarkforkian land-mammal age and mammalian faunal composition across the Paleocene-Eocene boundary. Univ. Michigan Papers on Paleontol. 26:1–197.Google Scholar
Schmidt-Kittler, N. 1984. Pattern analysis of occlusal surfaces in hypsodont hervivores and its bearing on morpho-functional studies. Proc. Koninklijke Ned. Akad. van Wetenschappen, 87B:453-480.Google Scholar
Sloan, R. E. 1983. Late Cretaceous and Paleocene mammal ages, magnetozones, rates of sedimentation and evolution. Geol. Soc. Am. Abstr. Progr. 15:307.Google Scholar
Sloan, R. E. and Van Valen, L. 1965. Cretaceous mammals from Montana. Science 148:220–227.Google Scholar
Szalay, F. S. 1969. Origin and evolution of function of the mesonychid condylarth feeding mechanism. Evol. 23:703–720.Google Scholar
Teaford, M. F. and Walker, A. 1984. Quantitative differences in dental microwear between primate species with different diets and a comment on the presumed diet of Sivapithecus. Am. J. Phys. Anthropol. 64:191–200.Google Scholar
Van Valen, L. 1978. The beginning of the Age of Mammals. Evol. Theory. 4:45–80.Google Scholar
Walker, A., Hoeck, H. N., and Perez, L. 1978. Microwear of mammalian teeth as an indicator of diet. Science. 201:908–910.Google Scholar