Sexual dimorphism in the caudal skull region of wistar albino rats: a geometric morphometric study

Year 2025, Volume: 72 Issue: 4 , 445 - 455 , 01.10.2025

Hasen Awel Yunus , İhsan Berat Kiliçli , Barış Batur , Muharrem Ayvalı Caner Bakıcı

https://doi.org/10.33988/auvfd.1667635

https://izlik.org/JA86WM84WP

Abstract

Wistar albino rats are recognized as essential model organisms in biomedical research due to their anatomy and genetic homogeneity. Their relevance in morphological and developmental studies makes them ideal subjects for investigating skeletal variations, including sexually dimorphic traits. This study aimed to examine the shape variations in the caudal region of the skull in Wistar albino rats, and especially to investigate the morphological differences between the genders. A total of 60 rats (30 males and 30 female) were analysed using geometric morphometric techniques, with shape data collected with via landmark-based analysis using MorphoJ. Statistical analysis was performed with PAST software. Principal Component Analysis (PCA) identified significant sexual dimorphism, revealing distinct morphological differences between male and female rats. Comparative visual assessments showed that females had a wider foramen magnum and condylus occipitalis, a more dorsally positioned opisthocranion, and a laterally broader linea nuchae compared to males. Additionally, ANOVA confirmed the presence of significant sexual dimorphism, demonstrating that the morphological characteristics of the caudal skeleton varied distinctly between male and female Wistar albino rats. These results suggest that the caudal skull region can serve as a useful indicator of sexual dimorphism, with geometric morphometrics offering a reliable method for detecting sex-related skeletal differences. This study not only advances the understanding of sexual dimorphism in rodents but also provides a framework for further investigations in comparative anatomy and evolutionary biology.

Keywords

Cranium , Geometric morphometrics , Principal component analysis , Rattus norvegicus , Shape analysis

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