Supplementary Material

Figure S1. Shape change along PC1 of modelled arching shape variation that was removed, since it is biologically irrelevant.

Figure S2. Removed shape change depicting sexual dimorphism and obtained by between-group PCA.

Figure S3. Removed shape change associated with centroid size (allometric shape variation).

Figure S4. Shape change between the three trout lineages, determined by DFA.

Figure S5. Scatterplot of the first two principal components of PCA depicting trout shape variation within Atlantic lineage. Wireframe graphs with marked landmarks represent shape change along the first and second principal components, from negative to positive end.

Figure S6. Scatterplot of the first two principal components of PCA depicting trout shape variation within Danubian lineage. Wireframe graphs with marked landmarks represent shape change along the first and second principal components, from negative to positive end.

Figure S7. Scatterplot of the first two principal components of PCA depicting trout shape variation within hybrid group. Wireframe graphs with 19 marked landmarks represent shape change along the first and second principal components, from negative to positive end.

Table S1. Eigeinvalues in the PCA for shape variation of Atlantic lineage trout.

Table S2. Principal component coefficients of corresponding Procrustes coordinates for first two PCs in the PCA for shape variation of Atlantic lineage trout.

Table S3. Eigeinvalues in the PCA for shape variation of Danubian lineage trout.

Table S4. Principal component coefficients of corresponding Procrustes coordinates for first two PCs in the PCA for shape variation of Danubian lineage trout.

Table S5. Eigeinvalues in the PCA for shape variation of hybrid trout.

Table S6. Principal component coefficients of corresponding Procrustes coordinates for first two PCs in the PCA for shape variation of hybrid trout.

© I. Špelić et al., Published by EDP Sciences 2021