Fig. 2. Simultaneous lateral and dorsal images from high-speed video, illustrating the four phases of a stride. Some kinematic landmarks are visible in the dorsal view. Time for each frame of this run (20.8 g lizard, 1.4 m s^–1) is shown in milliseconds in the upper right corner of each lateral view frame. The left foot is highlighted in both the lateral and dorsal images to show foot position at each phase. The blue circle in each lateral frame marks the same grid intersection to serve as a global point of reference that does not move with the lizard. Bars at the top of the figure represent footfall patterns for the right and left feet for this run. Colors of each section indicate stride phase, progressing from black to light gray: slap, stroke, recovery up and recovery down. See text for details on phase determination. The light blue box around the bars indicates when the foot is in the water. Numbers below the left foot footfall pattern indicate mean percent duration of each phase for all analyzed runs, simplified for clarity. Actual values (mean ± S.E.M.) from slap to recovery down averaged for 11 basilisk lizards are: 13.9±5.2%, 17.5±5.1%, 49.1±4.4% and 19.5±6.8%.

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