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Title page for ETD etd-11222012-233627


Type of Document Master's Thesis
Author Haupt, Ryan James
Author's Email Address ryan.j.haupt@vanderbilt.edu
URN etd-11222012-233627
Title Dental microwear texture analysis of dentin: can mammalian diets be inferred without enamel?
Degree Master of Science
Department Earth and Environmental Sciences
Advisory Committee
Advisor Name Title
Larisa R. G. DeSantis Committee Chair
Guilherme Gualda Committee Member
Molly F. Miller Committee Member
Keywords
  • enamel
  • ecology
  • dental microwear
  • dentin
  • dietary niche
  • Carnivora
  • Xenarthra
Date of Defense 2012-06-01
Availability unrestricted
Abstract
Dietary studies of xenarthrans are challenging as geochemical or microscopic examinations utilize enamel, which xenarthrans lack. The relative softness of dentin makes it potentially more prone to taphonomic alteration; thus, we aim to determine if dental microwear texture analysis (DMTA, which quantifies microwear in 3-D) of dentin can yield biologically meaningful results. Here we ask the following questions: i) are there consistent differences between dentin and enamel from teeth that have been subjected to the same food and bite forces (e.g., carnassial teeth); ii) can DMTA differentiate between extant and extinct xenarthrans with different diets (observed and morphologically inferred, respectively); and iii) is dentin microwear texture a reliable and comparable indicator of dietary ecology?

DMTA characters of different dental tissues in the carnassials of Florida panthers (Puma concolor coryi) were not significantly different from one another (except textural fill volume and heterogeneity); however, differences between tissues are highly variable. Dentin DMTA characteristic in sloths (Bradypus variegatus and Choloepus hoffmanni) and nine-banded armadillos (Dasypus novemcinctus) lack significant differences, except for greater textural fill volume and complexity in D. novemcinctus as compared to B. variegatus and Pilosa, respectively. All extinct taxa showed significant overlap in complexity and anisotropy, with values often below or above expected values from similarly feeding mammals with enamel teeth. Further, no differences were observed between like taxa over time. The high degree of overlap in most DMTA characters, despite divergent diets and differential grit consumption, questions the use of DMTA of dentin in extant and extinct xenarthrans.

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