A geometric morphometrics approach to sex estimation of infants from 0 to 6 years using the auricular surface

Abstract

Abstract Estimating biological sex is an essential tool for studying past population dynamics and cultural behaviour. Typically, it is not performed in non-adults before the onset of puberty, limiting the knowledge that can be gained from immature skeletal remains. This study used three-dimensional (3D) geometric morphometrics (GM) to examine sexual dimorphism and assess its effectiveness in estimating biological sex in infants aged 0–6 years using the auricular surface of the ilium. This approach was tested with 46 individuals (20 females and 26 males) from the Lisbon Identified Skeletal Collection. All specimens were digitised, and standard GM analysis was conducted. Apparent sex-related morphological differences in the auricular surface were observed in infants under one year, although these did not reach statistical significance at α = 0.05. Such differences were not identified in older individuals. These findings suggest that the auricular surface may potentially serve as a sex indicator in infants under one year, whereas sexual dimorphism appears to decrease in older individuals. This study demonstrates the potential of employing 3D GM for sex estimation in non-adult skeletal remains. Further research should explore additional iliac features for infant sex estimation, incorporate larger and more diverse samples, and potentially include Artificial Intelligence techniques.