Common Patterns of Skull Bone Fusion and Their Potential to Discriminate Different Ontogenetic Stages in Extant Birds

The degree of sutural closure between bones generally allows for the classification skeleton maturity in tetrapods. In mammals, skull was previously used as proxy to evaluate ontogenetic stage single individuals. However, due temporal variation, this process can be only applied among mammalian subclades, but not all mammals general. contrast, closures bird skulls could a more reliable clade adult birds commonly show high bone fusion. To test this, we studied series 18 extant species regarding presence an signal and compared results with changes size proportions. Univariate analyses indicate that fusion happens faster altricial than precocial birds. use PCoA multivariate regressions reveal follows common pattern thus identify different stages. general, spreads from posterior anterior ventral dorsal. measurements reflect rather interspecific allometry ontogeny. will help better compare stages maturation birds, including historical material osteological collections.