Extended Data Fig. 6: Shape differences associated with the first pair of PLS vectors (PLS1) for the beak block and the skull block for the main lineages of passerines.

Polar histograms summarizing angle comparisons between the PLS1 vectors for the beak (b) and skull (c) blocks. As orientation of PLS1 vectors is arbitrary, the maximum possible angle between PLS1 vectors is 90°. * indicates single angular comparison of the PLS1 vectors of Passeroidea excluding DF and HH.