Figure 2.

Prey capture sequence of S. leptorhynchus feeding on a mysid shrimp held by forceps. The measured kinematic variables are illustrated on the right: the head angle (θ; black), head to body angle at t=0 ms (ϕ₀; red). These angles were calculated based on six landmarks on the pipefish as indicated on the top drawing (1–2, anterior tip of the snout; 3–4, posterior region of the head at the level of the opercular opening; 5–6, approximately one head length further down the body). The determination of the centre of rotation (CR, green) based on the displacement of the upper jaw tip and the dorsal edge of the operculum between t=0 and 3 ms is illustrated in the drawing of t=3 ms. Point p (blue) is the mid-sagittal landmark on the pipefish's body where the ventral movement by the body during dorsal head rotation is approximately negligible. This point was determined from dorsal and ventral body contour tracings of the first frame (t=0 ms) and the frame at t=4 ms of the high-speed video by taking the xy-average of the points on the body where the corresponding contour lines have converged.