Fig. 5

Phylomorphospace of avian and longipterygid unguals, based on traditional morphometrics, grouped by pedal ecology. Grey lines indicate phylogenetic relationships. Line drawings of claws for selected taxa are provided for reference. Data is visualised with PCA (A) and LDA (B). In PCA (A), PC1 describes talon curvature and PC2 describes interdigital size variation. In LDA (B), LD1 describes the size ratio of digits II and IV to digit III and LD2 describes the size ratio of digits I and IV to digit III. See Additional file 1: Fig. S1 for precise character loadings. Taxon abbreviations: Lx1 Longipteryx chaoyangensis, Lx2 Longipteryx sp., Rp Rapaxavis pani, Sw Shanweiniao cooperorum, Sj Shenjingornis yangi