Corrected NUV − i colour versus stellar-mass diagram relation for galaxies in the Spring catalogue. Left: Sample divided according to the chromatic criterion of Boselli et al. (2014; see Fig. 2 therein), showing whether galaxies belong to the RS, the GV, or the BC. For each class, the linear regression analysis is given. Right: Same relation for the sub-sample of ETGs with detailed morphological classifications available (red), and of deficient (H I > 0.4, green) and non-deficient galaxies (H I ≤ 0.4, blue). The slopes of the linear regressions for the ETGs and the H I-deficiency classes are consistent with those corresponding to the three chromatic classes. The NUV and i magnitudes are corrected for dust attenuation (see Boselli et al. 2014).