MEPS prepress abstract  -  doi: 10.3354/meps07411

ABSTRACT: Within the brittle star genus Amphipholis, individuals are generally small, gonochoric, broadcast spawners and species often have restricted distribution areas. By contrast, Amphipholis squamata (Ophiuroidea, Echinodermata) is a species complex found worldwide, is hermaphrodite and broods its young. We used two complementary methods to estimate the selfing rates of the species found in the North Western Mediterranean Sea. Firstly, we analysed 190 specimens from Les Goudes using three co-dominant microsatellites and deduced the selfing rates from heterozygote deficiency, developing an original method to infer confidence intervals. Not a single heterozygote was discovered, leading to estimated selfing rates of 1.0 for all species, with an inferior limit between 0.77 and 0.98. In seven other European localities, not a single heterozygote was found. Secondly, we analysed 91 brooders and their 369 juveniles using seven nuclear markers. All progeny displayed the same DNA fingerprint as their parent, confirming that selfing rates are very high. Such high selfing rates, by contributing to colonization success (Baker’s rule), may solve the paradox of cosmopolitism for these ophiuroids lacking a larval phase, supposed to ensure dispersal.