Beyond Sexual Dimorphism: Ontogenetic Shape Variation in the Head Plates of Chalcides ocellatus (Forskål, 1775)
Makaleler > Tam Makale · 2026
Yazarlar: Batuhan Yaman Yakin, Ahmet Yesari Selçuk, Kerim ÇİÇEK, Dinçer AYAZ, Cemal Varol Tok
Journal of Herpetology, Uluslararası, Wos, 2026, cilt 60, ss 1-8
DOI: 10.1670/3180374
Özet
Head plate organization in lizards is closely associated with ecology, development and biomechanics. Despite their potential functional and taxonomic importance, geometric variation in the head plates of skinks remains poorly understood. Here we investigated sexual and ontogenetic differences in the shape and size of the head plates of Chalcides ocellatus (Forskål, 1775) in 281 preserved specimens from Mediterranean Türkiye, using a landmark-based geometric morphometric approach with 24 dorsal and 23 lateral landmarks. We found no significant difference between males and females in centroid size or shape for either configuration. Juveniles and adults, by contrast, differed markedly in both size and shape, and cross-validated discriminant analysis separated the two stages with 86.3–89.4% accuracy. Centroid size explained 8.3% (dorsal) and 9.4% (lateral) of total shape variation and accounted for about two-thirds of the juvenile–adult shape difference, but a significant difference remained after we corrected for size (P<0.002). Sex therefore has little influence on head plate shape in C. ocellatus; the main axis of variation is ontogenetic, and the juvenile–adult difference is largely, though not entirely, allometric.