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Date of Award
Thesis and Dissertation-ISU Access Only
Master of Science (MS)
Department of Sociology and Anthropology: Archaeology
Fred H. Smith
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.
Lacy, Katherine Marie, "The Etiology of the Horizontal-Oval Mandibular Foramen and a Reassessment of Its Usefulness for Paleoanthropological Studies" (2014). Theses and Dissertations. 222.