Skip to main content Accessibility help

Mammal-like occlusion in conodonts

  • Philip C. J. Donoghue (a1) and Mark A. Purnell (a1)


Conodont element function and feeding mechanisms are of considerable paleobiological importance, yet many details remain poorly understood and speculative. Analysis based on morphology, physical juxtaposition, and patterns of surface damage and microwear on pairs of Pa elements from individuals of Idiognathodus indicates that these elements crushed food by rotational closure, which brought the oral surfaces into complex interpenetrative occlusion. Other molariform conodont elements also functioned in this manner. Occlusion of this complexity is unique among nonmammalian vertebrates, and is all the more surprising given that conodonts lacked jaws. In addition to enhanced understanding of food processing in conodonts, our analysis suggests that many details of conodont Pa element morphology, which underpin taxonomy and biostratigraphy, can now be interpreted in a paleobiological, functional context.


Corresponding author

Previous address: School of Earth Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom


Hide All
Aldridge, R. J., Smith, M. P., Norby, R. D., and Briggs, D. E. G. 1987. The architecture and function of Carboniferous polygnathacean conodont apparatuses. Pp. 6376. in Aldridge, R. J. ed. Palaeobiology of conodonts Ellis Horwood, Chichester, England.
Aldridge, R. J. and Purnell, M. A. 1996. The conodont controversies. Trends in Ecology and Evolution 11: 463468.
Babcock, L. E. 1993. Trilobite malformations and the fossil record of behavioral asymmetry. Journal of Paleontology 67: 217229.
Baesemann, J. F. 1973. Missourian (Upper Pennsylvanian) conodonts of northeastern Kansas. Journal of Paleontology 47: 689710.
Bengtson, S. 1976. The structure of some Middle Cambrian conodonts, and the early evolution of conodont structure and function. Lethaia 9: 185206.
Bengtson, S. 1983. The early history of the conodonta. Fossils and Strata 15: 519.
Carroll, R. L. and Lindsay, W. 1985. The cranial anatomy of the primitive reptile Procolophon. Canadian Journal of Earth Sciences 22: 15711587.
Clark, J. M., Jacobs, L. L., and Downs, W. R. 1989. Mammal-like dentition in a Mesozoic crocodylian. Science 244: 10641066.
Crompton, A. W. and Hiiemae, K. 1970. Molar occlusion and mandibular movements during occlusion in the American opossum, Didelphis marsupialis L. Zoological Journal of the Linnean Society. 49: 2147.
DeMar, R. and Bolt, J. R. 1981. Dentitional organization and function in a Triassic reptile. Journal of Paleontology 55: 967984.
Donoghue, P. C. J. 1998. Growth and patterning in the conodont skeleton. Philosophical Transactions of the Royal Society of London B 353: 633666.
Donoghue, P. C. J. and Purnell, M. A. In press. Growth, function, and the conodont fossil record Geology.
Du Bois, E. P. 1943. Evidence on the nature of conodonts. Journal of Paleontology 17: 155159.
Fox, R. C., Youzwyshyn, G. P., and Krause, D. W. 1992. Post-Jurassic mammal-like reptile from the Palaeocene. Nature 358: 233235.
Gordon, K. D. 1982. A study of microwear on chimpanzee molars: implications for dental microwear analysis. American Journal of Physical Anthropology 59: 195215.
Janis, C. M. 1990. The correlation between diet and dental wear in herbivorous mammals and its relationship to the determination of diets of extinct species. Pp. 241259. in Boucot, A. J. ed. Evolutionary paleobiology of behavior and coevolution Elsevier, Amsterdam.
Jeppsson, L. 1971. Element arrangement in conodont apparatuses of Hindeodella type and in similar forms. Lethaia 4: 101123.
Jeppsson, L. 1979. Conodont element function. Lethaia 12: 153171.
Kemp, A. 1977. The pattern of tooth plate formation in the Australian lungfish, Neoceratodus forsteri Krefft. Zoological Journal of the Linnean Society 60: 223258.
Klapper, G. 1971. Sequence within the conodont genus Polygnathus in the New York lower Middle Devonian. Geologica et Palaeontologica 5: 5979.
Klapper, G. and Lane, H. R. 1985. Upper Devonian (Frasnian) conodonts of the Polygnathus biofacies, N.W.T., Canada. Journal of Paleontology 59: 904951.
Kuz'min, A. V. 1990. Asymmetrical pairs of platform elements of Polygnathus (conodonts). Paleontological Journal 1990: 6270.
Lane, H. R. 1968. Symmetry in conodont element-pairs. Journal of Paleontology 42: 12581263.
Lindström, M. 1964. Conodonts. Elsevier, Amsterdam.
Maas, M. C. 1991. Enamel structure and microwear: an experimental study of the response of enamel to shearing force. American Journal of Physical Anthropology 85: 3149.
Maas, M. C. 1994. A scanning electron-microscope study of in vitro abrasion of mammalian tooth enamel under compressive loads. Archives of Oral Biology 39: 111.
Müller, K. J. and Nogami, Y. 1971. U¨ber die Feinbau der Conodonten. Memoirs of the Faculty of Science, Kyoto University, Series of Geology and Mineralogy 38: 187.
Müller, K. J. 1972. Growth and function of conodonts. Pp. 2027. in. 24th International Geological Congress, Montreal.
Nicoll, R. S. 1985. Multielement composition of the conodont species Polygnathus xylus xylus Stauffer, 1940 and Ozarkodina brevis (Bischoff and Ziegler, 1957) from the Upper Devonian of the Canning Basin, Western Australia. Bureau of Mineral Resources Journal of Australian Geology and Geophysics 9: 133147.
Nicoll, R. S. 1987. Form and function of the Pa element in the conodont animal. Pp. 7790. in Aldridge, R. J. ed. Palaeobiology of conodonts. Ellis Horwood, Chichester, England.
Nicoll, R. S. 1995. Conodont element morphology, apparatus reconstructions and element function: a new interpretation of conodont biology with taxonomic implications. Courier Forschungsinstitut Senckenberg 182: 247262.
Norby, R. D. 1976. Conodont apparatuses from Chesterian (Mississippian) strata of Montana and Illinois Ph.D. dissertation. University of Illinois at Urbana-Champaign.
Pough, F. H., Heiser, J. B., and McFarland, W. N. 1996. Vertebrate life, 4th ed. Prentice Hall, Upper Saddle River, N.J.
Purnell, M. A. 1993. Feeding mechanisms in conodonts and the function of the earliest vertebrate hard tissues. Geology 21: 375377.
Purnell, M. A. 1994. Skeletal ontogeny and feeding mechanisms in conodonts. Lethaia 27: 129138.
Purnell, M. A. 1995. Microwear on conodont elements and macrophagy in the first vertebrates. Nature 374: 798800.
Purnell, M. A.In press. Conodonts: functional analysis of disarticulated skeletal structures lacking extant homologues. Pp. 129146. in Savazzi, E. ed. Functional morphology of the invertebrate skeleton. Wiley, Chichester, England.
Purnell, M. A. and Donoghue, P. C. J. 1997. Skeletal architecture and functional morphology of ozarkodinid conodonts. Philosophical Transactions of the Royal Society of London B 352: 15451564.
Purnell, M. A. and Donoghue, P. C. J. 1998. Architecture and functional morphology of the skeletal apparatus of ozarkodinid conodonts. Palaeontology 41: 57102.
Purnell, M. A. and von Bitter, P. H. 1992. Blade-shaped conodont elements functioned as cutting teeth. Nature 359: 629631.
Rensberger, J. M. 1978. Scanning electron microscopy of wear and occlusal events in some small herbivores. Pp. 523. in Butler, P. M., Joysey, K. A. eds. Development, function and evolution of teeth. Academic Press, New York.
Rensberger, J. M. 1995. Determination of stresses in mammalian dental enamel and their relevance to the interpretation of feeding behaviors in extinct taxa. Pp. 151172. in Thomason, J. ed. Functional morphology in vertebrate paleontology. Cambridge University Press, Cambridge.
Rhodes, F. H. T. 1952. A classification of Pennsylvanian conodont assemblages. Journal of Paleontology 26: 886901.
Robinson, P. L. 1956. An unusual sauropod dentition. Zoological Journal of the Linnean Society 43: 283293.
Sandberg, C. A. and Ziegler, W. 1979. Taxonomy and biofacies of important conodonts of Late Devonian styriacus Zone, United States and Germany. Geologica et Palaeontologica 13: 173212.
Sansom, I. J. 1996. Pseudooneotodus: a histological study of an Ordovician to Devonian vertebrate lineage. Zoological Journal of the Linnean Society 118: 4757.
Sansom, I. J., Smith, M. P., Armstrong, H. A., and Smith, M. M. 1992. Presence of the earliest vertebrate hard tissues in conodonts. Science 256: 13081311.
Smith, K. K. 1993. The form of the feeding apparatus in terrestrial vertebrates: studies of adaptation and constraint. Pp. 150196. in Hanken, J., Hall, B. F. eds. The skull. University of Chicago Press, Chicago.
Stamm, R. G. 1996. Reversals of misfortune: a new species? of Idiognathodus (Conodonta) based on functional surface morphology. In Repetski, J. E. ed. Sixth North American Paleontological Convention Abstracts of Papers Paleontological Society Special Publication. 8: 369. Smithsonian Institution Press, Washington, D.C.
Sweet, W. C. 1985. Conodonts: those fascinating little whatzits. Journal of Paleontology 59: 485494.
Teaford, M. F. 1988. Scanning electron microscope diagnosis of wear patterns versus artefacts on fossil teeth. Scanning Microscopy 2: 11671175.
Voges, A. 1959. Conodonten aus dem Untercarbon I und II (Gattendorfia-und Pericyclus-Stufe) des Sauerlandes. Pala¨ontologische Zeitschrift 33: 266314.
von Bitter, P. H. 1972. Environmental control of conodont distribution in the Shawnee Group (Upper Pennsylvanian) of eastern Kansas. University of Kansas Paleontological Contributions 59: 1105.
Weddige, K. 1990. Pathological conodonts. Courier Forschungsinstitut Senckenberg 118: 563589.
Wild, R. 1978. Die Flugsaurier (Reptilia, Pterosauria) aus der Oberen Trias von Cene bei Bergamo, Italien. Bollettino della Societa Paleontographica Italiana 17: 176256.
Wu, X.-C., Sues, H.-D., and Sun, A. 1995. A plant-eating crocodyliform reptile from the Cretaceous of China. Nature 376: 678680.
Young, J. Z. 1978. Programs of the brain. Oxford University Press, Oxford.
Zhang, S., Aldridge, R. J., and Donoghue, P. C. J. 1997. An Early Triassic conodont with periodic growth?. Journal of Micropalaeontology 16: 6572.


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed