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Date of Award

7-14-2014

Document Type

Thesis and Dissertation-ISU Access Only

Degree Name

Master of Science (MS)

Department

Department of Sociology and Anthropology: Archaeology

First Advisor

Fred H. Smith

Abstract

The lingula, located on the medial mandibular ramus, is a highly variable osteological feature of uncertain functional significance. A particular morphological variant of the lingula, called the horizontal-oval form of the mandibular foramen, has a much higher frequency in Neandertal samples than any in other hominin group. This trait has been used in morphological comparisons between Neandertals and modern humans as evidence of admixture or continuity. However, the etiology of this trait has never been satisfactorily investigated and therefore its efficacy for population studies is questionable. This study presents a new hypothesis that the morphology of the lingula is at least partially developed as a plastic response to heavy use of the masticatory apparatus.

An analysis of modern human and Neandertal samples demonstrated a significant correlation between the extremity of lingular bridge expression and severity of dental attrition, indicating that the morphology of the lingula is at least partially influenced by pressure placed on the masticatory apparatus. Still, the frequency of the trait is significantly higher in Neandertal samples, which suggests that there may also be a genetic influence on the rate and intensity of osteological growth in this anatomical region. However, due to the apparently significant influence of behavior on its morphology, we conclude that this trait should be used in studies of genetic relationships among samples only with caution.

Comments

Imported from ProQuest Lacy_ilstu_0092N_10333.pdf

Page Count

83

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