Sexual Dimorphism in the Fibular Extremities of Italians and South Africans of Identified Modern Human Skeletal Collections: A Geometric Morphometric Approach
by
,
Annalisa Pietrobelli
1,*, 
Rita Sorrentino
1,2,
Stefano Durante
3,
Damiano Marchi
4,5,6,†,
Stefano Benazzi
2,† and
Maria Giovanna Belcastro
1,† 
1
Department of Biological, Geological and Environmental Sciences, University of Bologna, 40126 Bologna, Italy
2
Department of Cultural Heritage, University of Bologna, 48121 Ravenna, Italy
3
IRCCS Azienda Ospedaliero-Universitaria di Bologna Policlinico S. Orsola-Malpighi, 40138 Bologna, Italy
4
Department of Biology, University of Pisa, 56126 Pisa, Italy
5
Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg 2050, South Africa
6
Natural History Museum of the University of Pisa, 56011 Calci, Italy
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Biology 2022, 11(7), 1079; https://doi.org/10.3390/biology11071079
Submission received: 1 June 2022
/
Revised: 8 July 2022
/
Accepted: 13 July 2022
/
Published: 19 July 2022
(This article belongs to the Special Issue Forensic Anthropology: New Methodological and Theoretical Perspectives in Forensic Human Skeletal Identification and Methods)
Simple Summary
The extremities of the fibula may reflect differences between males and females, although so far only few studies included this bone for post-cranial sex assessment. Our work explored shape and size variation between sexes in identified skeletal samples comprising different populations from Italy and South Africa and showed that fibular extremities are significantly smaller, with narrower articular surfaces in females than in males. Consistent sex-related differences are revealed in fibular form and size in Italians but not in South Africans. Potential application in forensic and bioarcheological contexts may benefit from the use of this approach.
Abstract
Fibular metric variations have revealed their potential in distinguishing between males and females; however the fibula remains scarcely analyzed in studies of sexual dimorphism. This work aims at investigating sexually dimorphic features in fibular proximal and distal epiphyses through geometric morphometrics methods. A total of 136 left fibulae, from two Italian and one South African identified skeletal collections were virtually acquired through CT and laser scanning and analyzed using geometric morphometric methods. Statistical analyses were performed on shape, form, and size variables. Results show that fibular epiphyses are smaller with narrower articular surfaces in females than in males in both extremities. Relevant sexual differences emerge in fibular form and size for the two Italian samples but not for the South African one, likely for its small sample size. Discriminant analysis on form principal components (PCs) offers accuracy above 80% when the samples are pooled, and reaches accuracy of 80–93% when the Italian samples are considered separately. However, our method on form PCs was not successful for the South African sample (50–53% accuracy), possibly due to the small sample size. These results show relevant morphological variation in relation to fibular form and size, with a degree of accuracy that indicates the utility of the present method for sexing human fibulae in both forensic and bioarchaeological contexts for Italian samples.
Keywords:
sex determination; human fibula; 3D geometric morphometrics
