Washington University in St. Louis Washington University Open Scholarship Arts & Sciences Electronic Theses and Dissertations Arts & Sciences Summer 8-15-2016 The on-MN asticatory Use of the Anterior Teeth Among Late Pleistocene Humans John Charles Willman Washington University in St. Louis Follow this and additional works at: https://openscholarship.wustl.edu/art_sci_etds Recommended Citation Willman, John Charles, "The on-MN asticatory Use of the Anterior Teeth Among Late Pleistocene Humans" (2016). Arts & Sciences Electronic Theses and Dissertations. 906. https://openscholarship.wustl.edu/art_sci_etds/906 This Dissertation is brought to you for free and open access by the Arts & Sciences at Washington University Open Scholarship. It has been accepted for inclusion in Arts & Sciences Electronic Theses and Dissertations by an authorized administrator of Washington University Open Scholarship. For more information, please contact [email protected]. WASHINGTON UNIVERSITY IN ST. LOUIS Department of Anthropology Dissertation Examination Committee: Erik Trinkaus, Chair Kari L. Allen Glenn C. Conroy Fred H. Smith David S. Strait The Non-Masticatory Use of the Anterior Teeth Among Late Pleistocene Humans by John C. Willman A dissertation presented to the Graduate School of Arts & Sciences of Washington University in partial fulfillment of the requirements for the degree of Doctor of Philosophy August 2016 St. Louis, Missouri © 2016, John C. Willman Contents Figures .............................................................................................................................................. v Tables ............................................................................................................................................. vii Acknowledgments......................................................................................................................... viii Abstract of the Dissertation .......................................................................................................... xvi Chapter 1. Introduction .................................................................................................................. 1 Biocultural adaptation and non-masticatory behavior ............................................................... 3 Analogy, extrapolation, and generalization: Issues of interpretation in paleobiology .............. 6 Research questions ................................................................................................................... 14 Thesis outline ............................................................................................................................ 16 Chapter 2. An introduction to dental wear .................................................................................. 18 Introduction............................................................................................................................... 18 Dental tissues ............................................................................................................................ 19 Dental wear basics: attrition, abrasion, and erosion ................................................................ 21 The effects of dental eruption sequence and timing on dental wear ...................................... 28 Dentoalveolar compensatory mechanisms in relation to dental wear .................................... 31 Dental occlusal variation ........................................................................................................... 40 Environmental factors influencing dental wear ........................................................................ 42 Non-masticatory, manipulative behavior and dental wear ...................................................... 44 Dental wear features and their interpretations ........................................................................ 47 Conclusions................................................................................................................................ 61 Chapter 3. Non-masticatory tooth-use in the Pleistocene ........................................................... 63 Introduction............................................................................................................................... 63 Neandertal and early modern human craniofacial shape, bite force, and dental wear .......... 64 Anterior tooth dimensions and discrete morphology .............................................................. 66 Dental tissue proportions .......................................................................................................... 70 Reconciling dietary and manipulative use of the anterior teeth .............................................. 73 Historical recognition of non-masticatory behavior among archaic humans .......................... 76 Direct analyses of non-masticatory dental wear on Pleistocene fossils ................................... 77 Conclusions................................................................................................................................ 85 ii Chapter 4. Materials ..................................................................................................................... 87 Introduction............................................................................................................................... 87 Sample descriptions .................................................................................................................. 87 Dental molding and casting for SEM analysis ........................................................................... 89 Rationale for fossil sample sub-grouping .................................................................................. 90 Chapter 5. Scaled occlusal macrowear gradients ....................................................................... 102 Hypotheses and Predictions .................................................................................................... 102 Brief rationale for analysis ...................................................................................................... 102 Methods .................................................................................................................................. 106 1. Dental metrics.................................................................................................................. 107 2. Occlusal Wear .................................................................................................................. 109 3. Data from other sources .................................................................................................. 113 4. Exclusion of third molars ................................................................................................. 114 5. Entire dentitions and partial dentitions were analyzed. ................................................. 115 Exploratory data analysis with bivariate plots .................................................................... 115 Results ..................................................................................................................................... 116 Individual anterior teeth versus first molars scaled occlusal wear gradients ..................... 120 Differential occlusal wear scores: Individual anterior teeth versus first molars ................ 122 Summary ................................................................................................................................. 128 Chapter 6. Antemortem enamel chipping of the anterior teeth ................................................ 131 Hypotheses and Predictions .................................................................................................... 131 A brief rationale for analysis ................................................................................................... 131 Materials ................................................................................................................................. 134 Methods .................................................................................................................................. 135 Antemortem versus postmortem chipping ......................................................................... 135 Ordinal scoring of enamel chipping ..................................................................................... 137 Comparisons with posterior dental chipping ...................................................................... 143 Results ..................................................................................................................................... 144 Conclusions.............................................................................................................................. 161 Chapter 7. Instrumental cutmarks on the labial enamel surfaces of anterior teeth ................. 163 Hypotheses and Predictions .................................................................................................... 163 iii A brief rationale for analysis ................................................................................................... 163 Materials ................................................................................................................................. 168 Methods .................................................................................................................................