Location of the sample objects (black dots with error bars) and B-type supergiants analysed in Paper I (open symbols) in two diagnostic diagrams, the sHRD (upper panel) and the HRD (lower panel). For comparison, loci of evolution tracks for stars rotating at Ω_rot = 0.568 Ω_crit (Ekström et al. 2012) are indicated for various ZAMS-masses. Isochrones for the model grid, corresponding to ages of log τ_evol ∈ {6.75, 6.85, 6.95, 7.05, 7.20} are depicted as dotted lines in the upper panel (increasing in age from top to bottom). For HD 91316 the luminosity as derived from the parallactic distance (ID#4a in Table 3) is depicted with a red symbol and marked accordingly. Error bars indicate 1σ uncertainty ranges.