Skull Shape Variation Among Domestic Duck Breeds and Their Wild Ancestor: Orvia, Pekin and Mallard

The skull is a critical structure for morphological characterisation across species and breeds, providing valuable insights into taxonomic classification and functional anatomy. This study aimed to investigate the cranial morphological variations among Orvia and Pekin domestic ducks and the wild Mallard (Anas platyrhynchos Linnaeus, 1758) using geometric morphometric methods. Furthermore, it examined whether these morphological characterisations could differentiate between domestic breeds and Mallard, and whether they exhibited allometric effects. In this study, the skulls of 59 one-year-old male ducks were analysed after slaughter. The skulls were modelled in 3D and subjected to geometric morphometric analysis. The results revealed significant differences in skull size among the Orvia, Pekin, and Mallard ducks (p < 0.001), with Orvia exhibiting the largest skull size. While overall shape differences were found among the duck groups, no statistically significant shape differences were observed between the Pekin and Mallard groups. The Orvia displayed broader skulls, whereas the Pekin and Mallard groups exhibited narrower and more elongated skull shapes. Additionally, a significant size-shape relationship was observed in the Pekin and Mallard groups, but no significant allometric relationship was found for the Orvia group. These findings contribute valuable insights into the morphological differentiation and anatomical understanding of domestic and wild ducks, offering a foundation for further comparative morphological studies. © 2025 John Wiley & Sons Ltd.