Figure 10 in Eigensurface analysis, ecology, and modelling of morphological adaptation in the falconiform humerus (Falconiformes: Aves)

Figure 10. Shape models representing along-axis trajectories through the canonical variates space for the CVA of flight style [CV-1 (first row), CV-2 (second row), CV-3 (third row) and CV-4 (fourth row)]. Models were calculated using the method of MacLeod (2007). Detailed inspection of the CV-1 models revealed that low scoring hovering taxa had humeri with larger, more pointed deltoid crests (DC), more rounded bicipital crests (BC) and more distinct bicipital furrows (BF); in higher scoring soaring taxa the humerus is more slender with a flatter appearance, the humeral head (H) is more domed and the external tuberosity (ET) is in a more proximal position. The CV-2 axis represented a shift between chase-hunting, perch-hunting, and low-flying species. From the CV-2 models it is clear that higher scoring taxa have more robust humeri with a thicker shaft (S), larger DC and BC. In specimens that have a lower score on CV-3 (which tended to be perch-hunters), the distal portion of the deltoid crest (DC distal) is larger than in higher scoring specimens, which have smaller DCs and less defined BFs. A high score on CV-4 is indicative of a flatter bicipital surface and a smaller DC (particularly the proximal portion) that extends further down the shaft.