Figure 1.

(a) Set-up for measuring bite forces (lateral view) and principal mandible organization in dragonflies (lower right, frontal view). The black arrow indicates the viewing angle for the three-dimensional model. (b) Three-dimensional representation of a dragonfly mandible in lateral view to show the position of the landmarks (red dots) and semi-landmarks (orange), the joints (asterisks), muscle force and bite force and joint-tip triangle (blue). Circles represent landmarks which are on the backside of the mandible. (c) Lateral section through the mandible of Onychogomphus forcipatus to show the location of the posterior (PR) and anterior (AR) dorsal ridges.