An Analysis of (hu)MANid Using the USF Donated Skeletal Collection: Estimating Sex and Ancestry for Edentulous Individuals

Graduation Year

2024

Document Type

Thesis

Degree

M.A.

Degree Name

Master of Arts (M.A.)

Degree Granting Department

Anthropology

Major Professor

Erin H. Kimmerle, Ph.D.

Committee Member

Gregory E. Berg, Ph.D.

Committee Member

E. Christian Wells, Ph.D.

Committee Member

Lorena Madrigal, Ph.D.

Keywords

anthropology, human identification, mandible, skeletal biology

Abstract

The Human Mandible Identification program, (hu)MANid©, enables anthropologists to estimate the sex and ancestry of unidentified skeletal remains from metric and morphoscopic variables from the mandible. The program is suitable for a variety of anthropological contexts, including forensic casework and bioarchaeological or paleoanthropological analyses. The purpose of this research project is to test the accuracy and applicability of the (hu)MANid program on edentulous mandibles. While the authors of (hu)MANid warn against data collection for edentulous mandibles, there are many circumstances in applied forensic casework where the unidentified person is edentulous. Edentulous individuals experience alveolar resorption, which is the loss of bone structure following the extraction or traumatic loss of teeth. Therefore, it is expected that the alveolar resorption that is experienced by edentulous individuals will affect the outcome and accuracy of (hu)MANid because morphological landmarks are remodeled through the processes of bone loss. The test sample consists of 40 dentulous mandibles and 40 edentulous mandibles, with equal quantities of males and females, from the USF Donated Skeletal Collection. Data were collected following the protocols established by Berg and Kenyhercz (2017b) for analysis in (hu)MANid. Three variables, GNI, HML, and XDA, were excluded from analysis of the edentulous sample because the landmarks of tooth crypts required for these measurements are not present in edentulous mandibles. Interobserver error in mandibular data collection for the entire sample (n=80) was also investigated in this research by comparing data collected by three observers. The data were analyzed using multiple quantitative methods to quantify the estimation results from (hu)MANid and the mandibular data sets. The results show that sex and ancestry are correctly classified in 77% of dentulous mandibles and 56% of edentulous mandibles. The dentulous results of this research are higher than the reported 70% correct classification reported by the (hu)MANid authors Berg and Kenyhercz (2017b). When using the sex-only approach in (hu)MANid, estimations were correct in 90% of dentulous mandibles and 85% of edentulous mandibles. The results of interobserver error indicate a high level of agreement between observers with almost all metric variables within 3 mm of variation with the only statistically significant differences occurring between observers for morphoscopic variables. Two case studies on fractured mandibles resulted in correct sex and ancestry classifications in (hu)MANid, which contributes to the discussion of (hu)MANid as an asset to the applied nature of forensic casework. This research demonstrates (hu)MANid is a reliable program for sex and ancestry estimation and the program may be reliably used in edentulous cases when the mandible is present without the rest of the cranium for analysis.

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