Palate Shape and Depth: A Shape‐Matching and Machine Learning Method for Estimating Ancestry from Human Skeletal Remains

Abstract

In the past, assessing ancestry relied on the naked eye and observer experience; however, replicability has become an important aspect of such analysis through the application of metric techniques. This study examines palate shape and assesses ancestry quantitatively using a 3D digitizer and shape-matching and machine learning methods. Palate curves and depths were recorded, processed, and tested for 376 individuals. Palate shape was an accurate indicator of ancestry in 58% of cases. Cluster analysis revealed that the parabolic, hyperbolic, and elliptical shapes are discrete from one another. Preliminary results indicate that palate depth in Hispanic individuals is greatest. Palate shape appears to be a useful indicator of ancestry, particularly when assessed by a computer. However, these data suggest that palate shape is not useful for assessing ancestry in Hispanic individuals. Although ancestry may be determined from palate shape, the use of multiple features is recommended and more reliable.

Macromorphoscopic trait expression in a cranial sample from Medellín, Colombia

“…Beyond some of the recently discussed issues surrounding Hispanic classifications in the United States [2,[6][7][8][9][10][11][12][13], Colombia faces a seemingly overwhelming task in the identification of mestizo [sic], or mixed, populations. The complex population and demographic history of Colombia makes ancestry assessment particularly difficult.…”

Quantification of Maxillary Dental Arcade Curvature and the Estimation of Biological Ancestry in Forensic Anthropology

“…Only intact casts with permanent dentition and normal occlusion were included in the sample. While casts often do not capture the most distal portion of the palate, the differences between hyperbolic and elliptical palate shapes are present in the shape of the anterior palate . Specifically, in a 2013 study of dry crania, Maier found that the anterior curvature of hyperbolic, elliptical, and parabolic palates is flat, founded, and pointed, respectively .…”

“…While casts often do not capture the most distal portion of the palate, the differences between hyperbolic and elliptical palate shapes are present in the shape of the anterior palate . Specifically, in a 2013 study of dry crania, Maier found that the anterior curvature of hyperbolic, elliptical, and parabolic palates is flat, founded, and pointed, respectively . In addition, Maier found that the angulation of the sides of the palate is markedly different in the hyperbolic, elliptical, and parabolic palate shapes.…”

“…Specifically, in a 2013 study of dry crania, Maier found that the anterior curvature of hyperbolic, elliptical, and parabolic palates is flat, founded, and pointed, respectively . In addition, Maier found that the angulation of the sides of the palate is markedly different in the hyperbolic, elliptical, and parabolic palate shapes. While a parabola has acutely angled sides, the hyperbola has nearly parallel sides.…”

Generating a Vertebrae‐based Method to Discriminate between Korean and U.S. White Male Casualties from the Korean War,

“…Based on the fact that some craniofacial features are observed in varying frequency among people of different ancestries, nonmetric traits indicative of a specific ancestry have also been studied . The relative prevalence of those traits has been used to generate novel statistical models . In addition, efforts to estimate ancestry using dental and mandibular morphoscopic and/or metric traits have recently led to the development of statistical tools such as rASUDAS and (hu)MANid .…”