Plot of canonical variate scores from the analysis pictured in Figure 7 against longitude, showing variation in scores in each group (males). Trimeresurus septentrionalis group species are plotted with triangular symbols in shades of red, while albolabris group species are plotted with circular symbols in shades of blue. Trimeresurus septentrionalis sensu stricto includes specimens from central/western Nepal and the western Himalayas in India, while T. albolabris sensu stricto includes specimens from China (including the island of Hainan) and northeastern Vietnam (as determined in the analysis in Fig. 6). Overlap in morphology between geographically proximate populations may be indicative of current gene flow.