Fig. 8

Reproductive stages according to Bronstein et al. [11] of the studied Diadema setosum population in Dodecanese island complex, observed in December 2019 and July 2020 samplings. A Stage II (recovering): clusters of previtellogenic oocytes formed in the ovarian germinal epithelium which may also occupy the central space of the female gametes. B, C Stage IV (mature): Ovaries (B) and testicular lumen (C) packed with mature ova and spermatozoa, respectively. Oocytes at different maturation stages are distinguished in the germinal epithelium. Ge germinal epithelium, Co coelom, NP nutritive phagocytes, Po previtellogenetic oocytes, Ov ova, Sz spermatozoa, Sc spermatocyte