Phase–space diagram for galaxies coded according to their distance from the best fit derived for HI gas-rich late-type systems. Filled black dots show galaxies within 1σ from the relation, filled blue dots show galaxies > 1σ above the relation, empty circles show galaxies 1σ–3σ below the relation, and filled dots show galaxies > 5σ below the relation. The solid lines delimit the different regions extracted from the simulations of Rhee et al. (2017) to identify galaxies in different phases of their infall into the cluster: first (not yet fallen), recent (0 <  τ_inf <  3.6 Gyr), intermediate (3.6 <  τ_inf <  6.5 Gyr), and ancient (6.5 <  τ_inf <  13.7 Gyr) infallers.