Spin parameter λ_Re of MaNGA galaxies as a function of their ellipticity ε. Colours indicate the density of the sample galaxies, with contours enclosing 20%, 40%, 60% and 80% of the data points. The dash-dotted black line represents the theoretically predicted locus for an axisymmetric galaxy with λ_Re, intr = 0.4 (assuming anisotropy δ = 0.7 × ε_intr) viewed over all inclinations, as proposed by Wang & Peng (2023). Throughout this work, galaxies above and below this curve are defined as the faster and slower populations, respectively. For comparison, the classical division between fast and slow rotators from Cappellari (2016) is also shown as the dashed red curve.