Morphological and molecular systematic review of Quatrefages, 1865 (Annelida: Eunicidae) species from South Africa.

A vast polychaete fauna is hidden behind complexes of cryptic and pseudo-cryptic species, which has greatly hindered our understanding of species diversity in several regions worldwide. Among the eunicids, Montagu, 1813 is a typical example, recorded in three oceans and with various species considered its junior synonyms. In South Africa, specimens previously misidentified as are now known as Lewis & Karageorgopoulos, 2008. Of the six Quatrefages, 1865a species recorded from the same region, three have their distributions restricted to South Africa while the others are considered to have worldwide distributions. Here, we evaluated the taxonomic status of the indigenous and investigated the presence of the widespread species Crossland, 1903 and Schmarda, 1861 in South Africa using morphological and molecular data. Our results reveal that is a junior synonym of , a species previously described from South Africa which is herein reinstated as a valid species. Both and are not present in South Africa and their status as being distributed worldwide deserves further investigation. Day, 1934 and the new species described here, n. sp., had been misidentified as and respectively. Thus, the number of species with distributions restricted to South Africa increased from three to five. This study reiterates the importance of implementing an integrated taxonomic framework to unravel local biodiversity.