Fig. 4.

Kinematic profile of a surgeonfish (Acanthurus chirurgus) bite. (A) shows lateral upper jaw rotation in a surgeonfish (A. chirurgus) throughout a bite sequence, where both jaw rotation and a head flick can be seen. The panels also show a representation of how jaw angle was measured throughout bite sequences from frontal view recordings. (B) Jaw angle for a bite by A. chirurgus. A value of zero represents no change to the angle between the jaws and rest of the head, whereas positive values represent jaw rotation to the Left side (observer’s frame of reference), and negative values, rotation toward the Right side. Numbers in circles represent the jaw angle at a specific time of the bite (dashed lines), as well as the panels seen in (A). (C) represents the velocity of the jaws and head (based on landmarks a2 and c2 respectively) during the same bite depicted in (A) and (B). (D) Example of multiple kinematic profiles of jaw angle from a species with jaw rotation abilities (A. chirurgus), and one without (Siganus magnificus). Note the kinematic variability between bites from A. chirurgus, relative to bites by S. magnificus. For data plots, smoothed lines have been produced, with raw data shown in the background.