Velocity dispersion measurements as a function of alpha abundances. LEWIS galaxies are colour-coded as in Fig. 1. Green triangles are UDGs analysed by Ferré-Mateu et al. (2023). Values of σ_eff for LEWIS are from Paper II. The dashed black line and the corresponding shaded region represent the average trend of massive early-type galaxies from ATLAS^3D survey (Cappellari et al. 2011). The light blue line and the corresponding shaded region represent the average trend ATLAS^3D survey together with the sample of dwarf galaxies in the Fornax cluster from the SAMI survey (Romero-Gómez et al. 2023).