“…Genetic differentiation has often been reported within the Mediterranean occidental basin in restricted dispersers (Boissin, Hoareau, Féral, & Chenuil, 2008; Rastorgueff, Chevaldonné, Arslan, Verna, & Lejeusne, 2014), but rarely in species with larval dispersal. Mediterranean corals showed strong population differentiation in this region (Ledoux et al., 2010; Masmoudi et al., 2016; Mokhtar‐Jamai et al., 2011), but the effective dispersal distance of these species is debated, and cryptic semi‐isolated ecotypes are suspected (Aurelle et al., 2017). Only the edible sea urchin Paracentrotus lividus shares a long larval duration and within‐basin genetic differentiation that was also found unexpected by (Penant, Aurelle, Feral, & Chenuil, 2013), although the genetic structure was not as strong and clear‐cut as found here in S. haemastoma .…”