Comparison of the spectral slope distributions of the primitive families in the inner main belt. The bin size is 0.87%/1000 Å. From left to right, top to bottom: sulamitis vs. Clarissa (this work), Polana vs. Erigone (the largest families, see Morate et al. 2016 for in-depth results), Clarissa vs. Polana, and Sulamitis vs. Erigone. Sulamitis and Erigone have been depicted in red, and Clarissa and Polana in blue. The vertical lines represent the mean values of the slope distributions. See text for more details.