Description and Quantification of Sexual Dimorphism of Pubic Body Shape in Hispanic Populations Using Elliptic Fourier Analysis

Abstract

Sex estimation is important in the creation of a biological profile for unidentified human remains, as positive identification cannot occur until the decedent’s biological traits have been determined and the range of possible matches has been narrowed. The pubic bone is cited as one of the best indicators of sex due to the constraints of childbirth. Current methods that use the pubic bone for sex estimation, however, rely on poorly defined and subjective observations that are susceptible to inter-and intraobserver error. Additionally, many of the methods currently in use are based on North American populations and thus may not necessarily model the variation seen in other populations around the globe. The aim of this study is to gain a better understanding of variation in pubic bone shape in Hispanic populations by separating the influences of sex, ancestry, and age at death. A total of 164 pubic bones from North American Hispanic and Chilean individuals were compared to 287 pubic bones from individuals of Euro-American ancestry from North American collections, using Elliptic Fourier analysis (EFA) of photographs, principal component analysis, and ANCOVA. EFA generated five effective principal components that collectively describe approximately 95% of the variation in the shape of the pubic body. Sex, age at death, and ancestry were all found to significantly influence shape but explained only 25% of the overall variation. The remaining 75% is likely influenced by variables that cannot be controlled for in anthropological analysis, underscoring how little variance in skeletal morphology is actually explainable.