Comparative Analysis of Mandibular Shape Variation in Domestic Geese and Ducks Using Linear and Geometric...

Area of Science:

• Avian morphology
• Comparative anatomy
• Biometrics

Background:

• Morphological differences between species and sexes are crucial for understanding evolutionary and ecological adaptations.
• Mandibular morphology in birds offers insights into diet, behavior, and phylogenetic relationships.
• Traditional linear morphometrics and advanced geometric morphometrics provide complementary approaches to quantify shape variation.

Purpose of the Study:

• To comparatively assess species- and sex-related differentiation in avian mandibles using two distinct morphometric methods.
• To evaluate the effectiveness of linear measurements versus 3D geometric morphometrics in discriminating morphological differences.
• To identify specific mandibular morphological variations between domestic geese (Anser anser domesticus) and domestic ducks (Anas platyrhynchos domesticus), and between sexes within each species.

Main Methods:

• Analysis of 80 avian mandibles: 40 from domestic geese (20 males, 20 females) and 40 from domestic ducks (20 males, 20 females).
• Application of traditional linear morphometrics, including specific measurements like LS.
• Utilisation of advanced 3D scanning and landmark-based geometric morphometric techniques for shape analysis.

Main Results:

• Linear measurements showed statistically significant species discrimination (p < 0.001 for LS), with high classification rates for geese (72.5%) and ducks (87.5%).
• Geometric morphometrics revealed clear separation between species groups, with PC1 explaining 50% and PC2 explaining 16.9% of shape variation.
• All linear measurements were significantly different between sexes in domestic geese (p < 0.001), while shape variation was relatively homogeneous within species groups.

Conclusions:

• Both linear and geometric morphometric methods are effective in identifying mandibular morphological differences between avian species and sexes.
• Geometric morphometrics provides a powerful tool for visualizing and quantifying complex shape variations.
• This study contributes valuable data on avian mandibular morphology, highlighting the utility of combined morphometric approaches for taxonomic and sexual dimorphism studies.