FIG. 1.

Kinematic movements in different backgrounds. (A, A') Two angles and three distances were ultimately recorded from each strike; see text for measurement details. Note that these two images represent different frames and do not necessarily reflect the maximum measurement for any variable. (B–G) Example strikes from six groups of analyzed fish. Leftmost panels show the frames as the fish starts to open its mouth; next is the panel immediately before food is enveloped; next is the frame at which the fish shows maximum hyoid depression; rightmost panel shows the fish after the mouth completely closes. Arrowheads indicate prey item before envelopment. Asterisk in (B) indicates the high degree of cranial elevation in young larvae. Arrows in (D, E) indicate large amount of jaw protrusion in WT and hyperthyroid adults. Numbers in bottom left corners indicate the milliseconds from the frame at which prey item is enveloped. Scale bar = 1 mm. WT, wild type.