Comparison of genetic distances within the Psammophis species, between sister species pairs, between non-sister species. The distances (y axis) are based on the ML tree. Horizontal bars with asterisks on top of the graph indicate significant differences in the observed genetic distances (p < 0.001; tested by the Tukey HSD post hoc test of ANOVA). The average distance between P. tanganicus and P. cornusafricae sp. nov. (0.127 subst. per site) is shown by the dashed line. The animal depicted is specimen NMP-P6V 76373 (sample JIR510) of P. cornusafricae sp. nov.