Chapter 12 - Sexual dimorphism variation in Fordisc samples

Abstract

Sexual dimorphism, the differences between males and females, is seen in many mammalian species and is expressed in varying degrees. Within humans, there is considerable variation in the levels of sexual dimorphism among different groups in cranial and postcranial measurements. In a forensic context, the different levels of sexual dimorphism affect sex classification accuracy, and we investigated their impact through linear discriminant function analysis and stepwise selection of variables from many groups using Fordisc 3 (Jantz & Ousley, 2005). We found that size and shape are factors in sexual dimorphism, and both should be used for the best classifications, but postcranial measurements showed greater shape dimorphism than did cranial measurements, both individually and in combination. As a general rule, forensic anthropologists should analyze unknown remains in comparison to the most appropriate reference groups available, and use postcranial measurements for sex estimation when possible.