CMR for A3667, A3376, and A168 using the OmegaWINGS photometric sample (grey filled circles). Overplotted are galaxies in the extended spectroscopic galaxy sample (Vulcani et al. 2022) with MORPHOT T-type morphologies. The dash-dotted line represents the 1σ above and below the fitted RS (solid), and the vertical dotted red line indicates the V-band magnitude limit (V₀ = −18) corresponding to the spectroscopic mass-completeness of log(M_*/M_⊙) = 9.48. The inset box indicates the slope (m), intercept (c), and standard deviation (σ) of the linear fit to the RS.