Figure 2.

(a) Right lateral view of the cranial anatomy of H. colliei indicating the jaw structures and muscles used in the biomechanical modelling of the feeding mechanism. (b) Right lateral view of the jaws of H. colliei indicating the position of the resolved adductive muscle force vector and the anterior and posterior bite points. The distance between the jaw joint and the resolved adductive muscle force vector is the resolved in-lever for jaw adduction. The distances between the jaw joint and the anterior and posterior bite points are the out-levers for anterior and posterior biting, respectively. AMA-α, adductor mandibulae anterior-α; AMA-β, adductor mandibulae anterior-β; AMP, adductor mandibulae posterior.