Results concerning the composite PCA made after size, blade-stem length index (IBS), tip-angle, asymmetry, and shape of the whole projectile (left columns), blade (central columns), and stem (right columns).

<p>Correlation values among the first two PCs and the variables are shown. Bolded values represent strong correlations among a variable and a PC. Explained variance of each PC among parentheses.</p

Results of the modularity analyses made on the three subsamples defined after Figure 3a.

<p>For each grouping we provide the multiset RV coefficient and associated P-value for two modularity hypotheses: blade/stem and tip/rest of the point. Values in parentheses correspond to results obtained after adjusting for reduction (IBS) effects. Significant RVs are bolded.</p

Consensus configurations.

<p>Consensus for the Type 1 (left), 2 (center), and 3 (right) groupings derived from the composite PC analyses presented on Fig. 3. Mean values of size (cs), blade-stem length ratio (IBS), tip-angle (TA), and asymmetry (AS) are presented.</p

Composite principal component analysis.

<p>Scatterplot of the two first principal components performed on the first PC of shape, size, IBS, TA, and asymmetry values. A) Whole point shape analyzed; b) only blade shape analyzed; c) only stem shape analyzed. The color of the points indicate classification of points as Bird IV (solid triangles), Bird V (empty circles) types according to Bird <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048009#pone.0048009-Bird1" target="_blank">[23]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048009#pone.0048009-Bird3" target="_blank">[25]</a>. T1, T2 and T3 represent arbitrary groupings aimed to repeat the modularity analysis on arrays of points sharing similar attributes.</p

Landmark configuration. Landmarks (large dots) and semi-landmarks (small dots) used in this study.

<p>Landmark configuration. Landmarks (large dots) and semi-landmarks (small dots) used in this study.</p

Modularity tests.

<p>Tests of modularity using the method of Klingenberg <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0048009#pone.0048009-Klingenberg2" target="_blank">[45]</a> based on 2D landmark data for 118 points. A) Pure shape dataset, blade/stem hypothesis; b) size-corrected dataset, blade/stem hypothesis; c) IBS-corrected dataset, blade/stem hypothesis; d) IBS-corrected dataset, tip/rest of the point hypothesis; The hypothetical modules tested are shown as red versus light-blue landmark configurations. The histograms show the distribution of the RV coefficients obtained from 10000 permutations of possible combinations of contiguous landmarks. The red arrow indicates the observed RV value. Significant modularity hypothesis are marked with an asterisk.</p

G_matrix

Additive genetic variance-covariance square matrix for skull shape

CovMatrix Symmetric component

Covariance matrix for the symmetric component of shape obtained by conducting the Procrustes ANOVA procedure implemented in Morpho

CovMatrix Asymmetry component

Covariance matrix for the asymmetric component of shape obtained by conducting the Procrustes ANOVA procedure implemented in Morpho

CS - CS.txt

Values of the symmetric centroid size and the logarithm of the symmetric centroid size