Effect of velocity substructure on the velocity dispersion – richness scaling relation for the SCGF catalogue with a different range of α_AD values. α stands for intercept, β – for slope and σ – for the intrinsic scatter. 2D contours show the 68% and 95% significance levels. Gaussian clusters are marked with solid purple lines and non-Gaussian clusters with dashed black lines. Solid orange lines show the cluster population with a marginal probability of having a substructure (between 85% and 95% confidence level).