The development and biomechanics of theropod teeth and comparisons with other reptiles: a functional analysis

  • Author / Creator
    Reichel, Miriam
  • Teeth are important for taxonomic studies. They are often the only remains found of certain vertebrates in the fossil record. This is because they are more resistant to weathering than most bones, they are small, and they are generally abundant. Most reptiles have homodont dentition, and the study of their teeth was neglected for a long time due to the lack of structures that facilitate their taxonomic identification. Recently it has been shown that many reptiles have teeth with morphological traits that reliably allow them to be identified to a narrow range of taxonomic groups. Additionally, the study of function and morphometrics of teeth in theropods and other reptiles has shown potential for understanding feeding behaviors. The objectives of this thesis are to describe the function and biomechanics of theropod dinosaur teeth, and compare them to other reptiles. Detailed analyses of histological sections of theropod and varanid lizard teeth show that in both taxa carinal development starts before enamel deposition. A concentration of dentinal tubules near the posterior carinae of all taxa may be related to the presence of larger carinae and denticles on the posterior side of teeth. Finite element analyses of tooth crowns of tyrannosaurids, varanids and Stegosaurus, plus the enamel microstructures in various reptile teeth show that an increased bending resistance is observed in taxa with labiolingually thickened teeth and columnar enamel microstructures. Additionally, the morphometric analyses of tyrannosaurid teeth, and the variation of carinal placements along the tooth rows help quantifying heterodonty. The highest degree of heterodonty was found in Tyrannosaurus, and this could be a result of the gigantism observed in this taxon. In conclusion, carinae (and denticles) develop in a variety of different taxa for reasons including phylogenetic relationships, tooth proportions, and tooth biomechanics. Also, heterodonty in tyrannosaurids is quantifiable, and each tooth family produces teeth that are specialized for different functions. The innovative techniques developed for these studies allowed a new approach to the study of reptile teeth. As the search for good modern analogs to fossil taxa continues, comparisons with distantly related taxa show great potential for functional analyses, besides taxonomic studies.

  • Subjects / Keywords
  • Graduation date
    Spring 2012
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
  • Specialization
    • Systematics and Evolution
  • Supervisor / co-supervisor and their department(s)
  • Examining committee members and their departments
    • Zelenitsky, Darla K. (Geoscience)
    • Caldwell, Michael W. (Biological Sciences)
    • Gingras, Murray K. (Earth and Atmospheric Sciences)
    • Murray, Alison M. (Biological Sciences)