Photo‐Realistic Statistical Skull Morphotypes: New Exemplars for Ancestry and Sex Estimation in Forensic Anthropology

Abstract

Graphic exemplars of cranial sex and ancestry are essential to forensic anthropology for standardizing casework, training analysts, and communicating group trends. To date, graphic exemplars have comprised hand-drawn sketches, or photographs of individual specimens, which risks bias/subjectivity. Here, we performed quantitative analysis of photographic data to generate new photo-realistic and objective exemplars of skull form. Standardized anterior and left lateral photographs of skulls for each sex were analyzed in the computer graphics program Psychomorph for the following groups: South African Blacks, South African Whites, American Blacks, American Whites, and Japanese. The average cranial form was calculated for each photographic view, before the color information for every individual was warped to the average form and combined to produce statistical averages. These mathematically derived exemplars-and their statistical exaggerations or extremes-retain the high-resolution detail of the original photographic dataset, making them the ideal casework and training reference standards.

A quantitative approach for sex estimation based on cranial morphology

“…A number of studies have adopted metric approaches for estimation of sex using the cranium (e.g., Brasili, Toselli, & Facchini, ; Caple & Stephan, ; Kranioti, İşcan, & Michalodimitrakis, ), while more generalized use of geometric morphometric techniques has facilitated studies that focus on capturing the overall morphology of the cranium or of specific cranial structures (e.g., Bigoni, Velemínská, & Brůžek, ; Chovalopoulou et al, ; Nikita, ). Among those focusing on the morphology of specific cranial structures using geometric morphometry, Garvin and Ruff () explored sexual dimorphism in the supraorbital ridges and mental eminence of US males and females.…”

An Automated Two‐dimensional Pairwise form Registration Method for Pair‐matching of Fragmented Skeletal Remains

“…Shape and form analyses have become more popular in physical and forensic anthropology (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) with a few studies focused on matching algorithms (6,(10)(11)(12)(13)(14)(15). With the adoption of shape analysis, the literature on osteological sorting has started to shift from linear metric approaches (16)(17)(18)(19)(20)(21)(22)(23) to shape and form approaches (10)(11)(12).…”

An Automated Two‐Dimensional Form Registration Method for Osteological Pair‐Matching

“…Shape analysis has become commonplace in biological fields (4)(5)(6)(7)(8)(9)(10), such as physical anthropology (11,12), and more recently forensic anthropology (13)(14)(15)(16)(17)(18)(19)(20)(21)(22). However, much of the existing literature relies on methods designed for analyzing shapes in a different manner than is required for pair-matching.…”