Figure 1

Shape differences between morphs assessed with geometric morphometrics. (A) Landmarks marking the anterior tip of the ethmoid plate (EP, leftmost landmark), lower jaw (MC, Meckel’s cartilage) and hyoid arch (HA). (B) Pairwise Mahalanobis (upper panel) and Procrustes distances (lower panel) between morphs and their significance obtained with 10.000 permutations. AC, Aquaculture charr from the Hólar breeding stock; LB and SB, Large and small benthivorous charr, respectively; PL, Planktivorous charr. ***P <0.001; **P <0.01; *P <0.05. (C) and (D) Scatterplots of the canonical variate (CV) analysis scores for four morphs of Arctic charr (AC, Black dots; LB, Blue dots; PL, Green dots; SB, Red dots). Wireframes depict shape changes associated with the two CVs shown in each graph (CV1 and CV2 in part (C) and CV1 and CV3 in part (D)). In the wireframes, the shape corresponding to the extreme negative CV score is shown in black, and the shape corresponding to the extreme positive CV score is shown in red. The scale factor is in units of Mahalanobis distance and is set to 6. Confidence ellipses are set to 90%.