Marine Annelida diversity and taxonomic knowledge in South Africa: A critical review

This is the first comprehensive review of marine Annelida in South Africa, including polychaetes, oligochaetes, sipunculids, thalassematids (echiurans) and siboglinids. The literature was reviewed for taxonomic descriptions and revisions, and the validity of taxa described in southern Africa, including those synonymised with globally distributed species, confirmed. Since 1766, >160 manuscripts authored by >90 researchers reported, described and revised >760 annelids from South Africa. About 46 % of the species are indigenous (of which >15 % were described by South African John Day). Revisions conducted since the 1970s re-identified 49 species previously considered cosmopolitan as indigenous, with several recorded here for South African species lists for the first time. Just over 50 species have junior synonyms that were originally described in southern Africa, and most probably represent valid taxa. Less than 3 % of the non-indigenous taxa are alien, with the rest requiring taxonomic revision. Of the 67 families recorded locally, most revisions have been conducted on Eunicidae, Lumbrineridae, Nereididae, Polynoidae, Serpulidae, Spionidae, Syllidae and Terebellidae. Genetic data (mainly mitochondrial cytochrome oxidase I) are available for less than 10 % of marine annelid taxa reported locally, limiting detection or identification using metabarcoding or environmental DNA studies. Future research should focus on Oligochaeta, Thalassematidae and Sipuncula, and subtidal, deep water and estuarine habitats. Revisionary work should prioritize taxa for which material identified by local experts like John Day and Ramlal Biseswar are available, as they represent material on which local keys are based.