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Description
Uncovering how ecologically diverse the earliest eutherians were is a difficult and important challenge for mammalian paleontology. As the pertinent fossil remains are mostly limited to small isolated dental elements, this thesis uses the patterning and extent of large scale dental wear to infer aspects of the dietary ecology of an early group of sympatric stem eutherians. The fauna sampled for this study comes from the Upper Cretaceous Bissekty Formation, in the Dzharakuduk region of Uzbekistan; and represents the earliest recorded eutherian dominated mammalian community. To describe the variation seen in large scale wear, and to test the effects that either relative age or phylogenetic position have on its accumulation, several univariable and multivariable statistical analyses are reported. These include an Analysis of Covariance (ANCOVA) and multivariable ordinations performed using the sampled upper and lower molars separately. All data used in this study was collected through the use of micro-computerized tomographic (uCT) images of the fossil material; and two linear regressions are reported here that quantify the difference seen between traditional two-dimensionally projected and novel three-dimensionally embedded area measurements. The results confirm the validity and usefulness of uCT in the analysis of dental wear, and suggest new quantitative wear variables made available by this approach. The statistical analyses performed here detect significant ecological diversity among the eutherian component of the Bissekty Fauna, and find that relative age is not an influence on the patterning of molar wear. The Bissekty zhelestids in particular are characterized by a high proportion of grinding wear that suggest a derived, largely herbivorous diet.
