FIG. 7.—The evolutionary origin and loss of key courtship traits in Ensatina, Aneides, and Plethodon. Character origins are shown with solid rectangles; loss is shown with open rectangles: TSW ¼ tail-straddling walk module, c-TSW ¼ circular tail-straddling walk, tbf ¼ turning back towards the female during TSW, tpd ¼ transdermal pheromone delivery (tpd1 and tpd2), opd ¼ olfactory pheromone delivery, fd ¼ foot dance, ps ¼ pulling and snapping, tw ¼ tail wagging, and mgr ¼ mouth grasping. The time of origin or loss for each trait is bounded by the times at the ends of the branch on which it resides. Timecalibrated phylogeny based on Kozak et al. (2009); time scale shown in millions of years.