Residual velocities as a function of the heliocentric distances of the studied star clusters. The vertical dashed lines represent the boundaries of the SMC Main Body (Piatti 2021a), while the horizontal red line represents the lower residual velocity limit adopted in this work for the star clusters outside the SMC Main Body. Star clusters pertaining to different substructures (Dias et al. 2016) are drawn in different colors, as indicated in the top-right panel. The symbol sizes are proportional to N^eff.