Left: the dynamically recovered stellar mass-to-light ratios ϒ_*(r) evaluated at radii r = 2.″5 and r = 7.″5 vs. SSP age in the corresponding annulli. Right: the same but for the total mass-to-light ratio (including dark matter). For this comparison, we calibrated all mass-to-light ratios to the z band. The mass-to-light ratios appear to be anticorrelated with age. If the IMF is assumed to be universal across formation epochs, then this trend is counterintuitive, because one would expect that mass-to-light ratio is positively correlated with the time passed since star formation. The dotted line indicates the expected present-day z-band mass-to-light ratio for a single stellar population with a universal Kroupa IMF and a metallicity of [Z/H] = −0.3 (C. Maraston 2005) as a function of its age.