The understanding of South African polychaetes has greatly benefited from John Dayʼs seminal contributions, particularly his 1967 monograph. However, many of the species he documented were described as non-endemic or cosmopolitan. Some of these may in fact represent distinct species, leading to an underestimation of the true diversity of Southern African polychaetes. This study examines four species belonging to the highly diverse and morphologically variable family Syllidae. Three of these were previously identified as Syllis prolifera, Syllis variegata, and Paraehlersia ferruginea based on Day’s monograph. Detailed morphological analyses and comparisons with Day’s material reveal that these specimens represent new species, which are described and illustrated here. The fourth species was identified as Syllis amicarmillaris following Simon et al. (2014), despite its occurrence approximately 250 km from the type locality. Our observations confirm that this population corresponds to S. amicarmillaris, with the only noted differences being related to the smaller size of our specimens, compared to the type description. Our results suggest that syllid diversity in South African waters is likely underestimated, and that further expanding molecular sampling —especially within syllid species complexes— will be essential to uncover hidden diversity and clarify species boundaries.

Background: Alien species are a growing concern due to harmful impacts on the environment and ecosystem services. However, relatively little information exists about alien marine species in Namibia. Objectives: To compile the first list of marine alien and cryptogenic species for Namibia. Methods: A systematic search of the primary literature was combined with searches of historic taxonomic literature, the World Register of Introduced Marine Alien Species (WRiMS), the Global Biodiversity Information Facility (GBIF), the Ocean Biodiversity Information Systems (OBIS), iNaturalist and the grey literature, to identify alien and cryptogenic species that have been reported from Namibia. Results: A total of 26 alien and 12 cryptogenic species have been documented along the Namibian coast. Most species have a Northern Hemisphere native range and more than half were first recorded pre-2000. The primary likely mechanism of introduction has been shipping [i.e., hull fouling (63% of species), ballast water (20%) and ship boring (7%)] but mariculture (10%) has also played a role. The Ikaras Region supports the most alien (23) and cryptogenic (11) species. This likely reflects the presence of the busy Robert Harbour in L & uuml;deritz, the proximity to the South African west coast, which is known to support >60 alien species and the fact that this region is the most accessible and well studied. Conclusion: This study provides first insights into marine invasions in Namibia, but dedicated surveys for alien taxa will improve our understanding of the full extent of invasions along the Namibian coast.

The global decline in biodiversity, driven by habitat loss, overexploitation, climate change, biological invasions, and illegal trade, poses significant challenges for conservation management. Although many South African ecosystems and species are under threat, effective conservation efforts are hindered by incomplete foundational biodiversity data and assessments, caused by taxonomic gaps and unverified distributions. DNA barcoding has emerged as an invaluable tool for species identification and classification of biodiversity. While substantial barcoding progress has been made, for many taxa, others remain underrepresented in sequence databases. This study evaluates the status and progress of DNA barcoding in South Africa through a gap analysis, comparing verified species checklists with barcoded sequences from the Barcode of Life Database (BOLD) and GenBank to assess taxonomic and geographic representation. A literature review (2003-2023) highlights applications across terrestrial, freshwater, and marine habitats. Of the 931,476 South African species barcode records, 52% were publicly available. Although the insects dominated with the highest number of records and BINs, reptiles had the highest taxonomic representation. Plants and fungi were underrepresented (16.1% and 2.8%, respectively). Regionally, Mpumalanga and Limpopo provinces showed the highest BIN counts, while North-West and Free State provinces had the lowest. The majority of barcode records were for mtDNA genes such as cytochrome c oxidase subunit I (COI) and were contributed by both local and international institutions. Discrepancies between GenBank records and those mined by BOLD indicated that many GenBank sequences for South Africa have poor quality metadata, including geographic sampling locality information. While significant progress has been made across taxa, further efforts are needed to expand species and geographic coverage, enhance sequence quality, improve species metadata, and resolve inconsistencies in BIN assignments, particularly for underrepresented groups such as plants and fungi. These advances would strengthen biodiversity assessments and support conservation efforts in South Africa.

Lumbrineris magalhaensis Kinberg, 1865 (Annelida: Lumbrineridae) is a marine polychaete worm that was first described from the Magellan Strait, Chile; thereafter it was also reported in sub-Antarctic, temperate and tropical regions, where it was likely misidentified. In South African waters, Lumbrineris magalhaensis may have been erroneously synonymised with Lumbriconereis pettigrewi McIntosh, 1885, which was first described from off the Cape of Good Hope. Specimens collected from the Knysna Estuary on the south coast of South Africa were recently identified as Lumbrineris magalhaensis based on identification keys for local fauna. However, the specimens all differ from descriptions of the type material and previous descriptions of Lumbrineris magalhaensis, as well as from re-examined specimens of Lumbriconereis pettigrewi (three syntypes, collected off the Cape of Good Hope, South Africa), with regard to prostomium shape, numbers of teeth on maxillae III and IV, shape of maxilla II, size and colour of maxilla II connecting plates, arrangement of limbate chaetae and the habitat. The specimens from Knysna have therefore been designated as Lumbrineris knysnaensis van Niekerk, Kara, Alvarez Aguilar & Simon sp. nov. Furthermore, the synonymisation of Lumbriconereis pettigrewi and Lumbrineris magalhaensis has been reversed, owing to differences in prostomium shape, number of teeth on maxilla IV, depth of collection and habitat type; therefore, Lumbrineris pettigrewi comb. nov. reinst. is supported. Analysis of mtDNA cytochrome c oxidase subunit I (COI) indicated that the Knysna specimens represent a single species and do not match any other known species, corroborating the morphological data. Further morphological and genetic investigations of Lumbrineris magalhaensis from other regions are needed to resolve the taxonomy of this species.ZooBank: This article is registered in Zoobank under urn:lsid:zoobank.org:pub:D740599A-4A9B-4DC0-8948-C7BB7628FE5DThe new species is registered in ZooBank under urn:lsid:zoobank.org:act:03727E90-9743-460F-ABCA-BEBF9FBB1CD2

Determining how organisms respond to environmental gradients or variability is a central theme in ecology which is used to predict niche occupation. In this study we assessed the natural population variability of a locally widespread nereidid Ceratonereis (Composetia) keiskama to determine whether its broad distribution can be used to infer a generalist autecological niche. This was examined in the recently discovered estuarine-like stromatolite-forming pools in South Africa where this polychaete also occurs. Results suggest that neither temperature nor salinity were important predictors of C. keiskama density, attesting to its broad ecophysiological tolerance. Instead, sediment properties were correlated with presence in estuaries and the stromatolite pools, which suggests that foraging conditions or biotic interactions are more important autecological drivers. Notably, C. keiskama density in the stromatolite pools was on average an order of magnitude higher than in most estuaries and this species is the dominant epibenthic macroinvertebrate within the stromatolite sediment, suggesting an opportunistic occupation of this niche. These findings highlight the importance of linking species ranges to niche occupation of diverse habitat types, and it frames future work which should address the population level connectivity and gene transfer between such different environments.

Regeneration is critical for survivorship after injury, sublethal predation, and asexual reproduction; it allows individuals to recover, potentially enabling populations of bait species to overcome the effects of bait collection through incidental asexual reproduction. Opportunities for regeneration are created when worms break during collection (which happens more often than not) and are thrown back into the estuary. Additionally, the trade and movement of bait could result in the range expansion of invasive species. This study investigated bait collection habits of local fishermen and the in situ incidence of regeneration in the estuarine moonshine worm, Diopatra aciculata. The evidence shows that this species is capable of anterior and posterior regeneration. The disproportionately small percentage of worms that seem to be recovering from the degree of damage that may be inflicted during bait collection suggests that regeneration may not help worms to withstand the effects of bait collection. However, the continuous movement and discarding of even small numbers of bait in other estuaries can lead to range expansion through incremental build-up, forming new populations, if these fragments are large enough to regenerate.

The Knysna Estuary is a large, clear-water embayment and one of the most important estuaries for conservation in southern Africa. The estuary is detritus-dominated and the benthic food webs have low diversities of carnivores, which may make the estuary vulnerable to invasions through the empty niche hypothesis. In the last two decades, the Knysna Estuary has experienced an increase in the population of the cryptogenic and apparently omnivorous estuarine moonshine worm (Diopatra aciculata). Our goal was to describe the trophic role of D. aciculata. We measured carbon and nitrogen stable isotopes in all the common macrophytes and macroinvertebrates across four seasons to 1) establish the isotopic landscapes of three disparate sites within the Knysna Estuary where D. aciculata occurs, 2) establish whether the trophic level of D. aciculata matches those of other common macroinvertebrates, and 3) establish whether the isotopic niche of D. aciculata overlaps with those of syntopic macroinvertebrates. Communities at the different sites differed in food web width, most likely due to differences in primary producer diversity. Our findings suggested that D. aciculata is a facultative carnivore, and some sub-populations are sustained primarily by animal tissues. Isotopic niche overlap analysis showed that direct competition with other common macroinvertebrate consumers is doubtful and D. aciculata occupies a unique niche within the estuary.

The current study investigates the final unresolved cosmopolitan species of Marphysa in South Africa, Marphysa corallina, collected from KwaZulu Natal, Eastern and Western Cape provinces, together with another species collected from northern KwaZulu Natal. Morphological and genetic data prove that M. corallina, originally described from Hawaii, does not occur in South Africa. The curvature of the inner base on maxilla I, the elevated inner base of maxilla II, and the ventral cirrus as a transverse welt with a rounded tip allow us to identify it as a new species of Treadwellphysa, T. izinqa sp. nov. (common name: brown wonderworm). Characteristic traits include the basal reddish and distal golden colour of the subacicular hook, the ear-shaped postchaetal lobe, and tridentate falcigers which is reported for the first time for the genus. This species is harvested as bait on the south coast of SA, although less frequently than the more common blood wonderworm, Marphysa haemasona Quatrefages, 1866, and can be distinguished by its more uniform brown colouration and white-tipped antennae. A second species, Marphysa mzingazia sp. nov., is characterized by red eyes, six branchial filaments extending to the posterior end, the golden aciculae in posterior chaetigers, weakly bidentate yellow/brown subacicular hooks, and the presence of similar sized spinigers along the body. A molecular analysis based on cytochrome oxidase I fragments confirm both taxa as different species. A key for all South African species of Marphysa is included.

This systematic review analysed scientific publications to identify relevant research about the impact of alien polychaete species around the world, using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analysis) guide. The criterion for inclusion was studies published in English, with the key terms (e.g. ‘impact’, ‘alien species’, ‘polychaetes’) in the title, abstract and keywords. The literature search was conducted in Scopus and Web of Science from April to December 2020. The search resulted in 150 papers that included information about impact of alien polychaete species. Of these studies, 98% were published in the last 25 years, reporting on the impact of 40 species in 18 regions of the world. Sixty-one per cent of the research was conducted in the Baltic Sea, South-west Atlantic and Mediterranean Sea. The most frequent type of study was field surveys (46%) and the most studied system was open coast areas (36%). The species with the highest number of publications about their impacts were Ficopomatus enigmaticus , Marenzelleria viridis , Sabella spallanzanii and Boccardia proboscidea . Based on evidence of their most severe documented impacts in their introduced ranges, the impact mechanisms (IMos) of the alien polychaete species were strongly related to their biology and lifestyles. We found that species that build conspicuous reefs and tube-dwellers mainly showed physical and structural impact on ecosystems; shell-borers, mainly parasitism and infauna species, showed mainly chemical, physical and structural impacts on ecosystems. Some recommendations for the study of alien polychaete species are discussed.

Previous identifications and characterisations of southern African polychaete species are brief and many are based on northern hemisphere taxa. Hence, many species from family Nereididae were either misidentified or incorrectly synonymised with species from other regions, leading to an incomplete understanding of the nereidid diversity and biogeography in the region. As such, a thorough taxonomic review was conducted on museum specimens of the convoluted genus Neanthes Kinberg, 1865 present in southern Africa, with emphasis on those originally described from South Africa: Neanthes agulhana (Day, 1963), N. operta (Stimpson, 1856), N. papillosa (Day, 1963), and N. willeyi (Day, 1934). Morphological examinations based on the type material revealed that N. capensis is valid over N. willeyi, and N. agulhana is transferred to Nereis after redescribing the species; likewise, the alien status of both species in the Mediterranean Sea is questioned and rejected, respectively. The original type specimens of N. papillosa and N. operta are lost, although the former is recognised as valid based upon the original description, whereas the latter species is now considered indeterminable. Nereis polyodonta Schmarda, 1861, previously synonymised with N. operta, is reinstated and transferred to Neanthes. The current taxonomic status of the remaining Neanthes species recorded from southern Africa is pending a thorough re-evaluation. The phylogenetic status of this genus was investigated using a mitochondrial data set of Neanthes species globally, generated in this study or mined from GenBank and BOLD, in addition to other genera in Nereididae. Phylogenetic analysis suggests that Neanthes is polyphyletic; nonetheless, the majority of the relationships within the genus could not be resolved. A global scale assessment with an in-depth integrated approach in taxonomy is needed to distinguish this genus.

Polychaete worms are used widely as bait in South Africa, but common names are not used consistently among fishers or in the literature. This can have implications for conservation, since different polychaete species will not be equally vulnerable to exploitation, and uncertainties about the names of species make it difficult to monitor harvests to assess catch rates. This study develops a consensus view of English and Afrikaans common names for known bait species, building on names already used by fishers and in the literature. The greatest (but not complete) consensus in use of names among fishers and in the literature was for species in the families Arenicolidae, Eunicidae and Nereididae. However, most species are known by multiple common names, some common names are used for multiple species in different families, and the use of at least one name has changed. By applying principles like those used to develop scientific names, we propose a binomial naming system that includes a collective common name that applies to the family or genus, and which, for most species, is already used by fishers, as well as qualifying names that apply to the individual species. The qualifying names may refer to a morphological character that can be observed in the field, its distribution, ecology or the specific name. Research is needed to develop consensus names in isiXhosa.

Originally published in 1967, John H Day’s work ‘A monograph on the Polychaeta of southern Africa’ is still used widely to identify polychaetes. However, ongoing taxonomic revisions have revealed that several putative cosmopolitan or locally widespread taxa contained in the monograph are complexes of species with discrete distributions, globally and locally. This study therefore aimed to develop lists of taxa, including unresolved cosmopolitan and widespread indigenous species, that should be prioritised for revision to unlock their hidden diversity. A total of 609 species (56 families and 316 genera) were scored according to their time since description, global and local distribution, availability of genetic data and vouchers, alien status and economic importance, and then ranked. At least half the taxa reported locally are unresolved cosmopolitan complexes, and a quarter have wide local distributions, probably hiding cryptic diversity. Accordingly, we estimate that approximately 500 polychaete species are still undescribed in southern Africa. The four highest-scoring families (Syllidae, Nereididae, Spionidae and Eunicidae) comprise 25% of the species and 53–85% of the unresolved cosmopolitans, while multiple species are considered pests, used as bait or possible aliens. Prioritised genera (e.g. Eunice, Syllis, Nereis, Prionospio, Dipolydora) and species (e.g. Pseudonereis variegata) are usually members of prioritised families, but some species are not (e.g. Sabella cf. pavonina, Fimbriosthenelais zetlandica, Paleanotus chrysolepis, Gunnarea gaimardi, Capitella capitata). All taxon levels should therefore be considered to ensure that all species most in need of revision are identified. Ways to facilitate revisions are discussed.

Polychaete worms of the Polydora-complex (commonly referred to as polydorins) include some of the most common pests of cultured molluscs. Modern culture of molluscs, particularly oysters, is associated with large-scale movement of stock which facilitates movement of polydorins either as "hitchhikers" on the transported molluscs or in the packaging. In 2009, a species identified as Polydora cf. ciliata Johnston, 1838 was reported from oysters in a culture facility in Port Elizabeth, South Africa. Since then, more specimens of this species were recorded on farmed oysters from Namibia, Kleinzee and Paternoster on the west coast of South Africa, but tentatively reidentified as Polydora cf. websteri Hartman in Loosanoff and Engle, 1943 based on morphology and limited genetic evidence. The main aim of this study is therefore to clarify the identity of these specimens by integrating morphological and genetic (mitochondrial COI, Cyt b and nuclear 18S rRNA) evidence. Specimens from South Africa match the morphology of the lectotype of P. websteri and are morphologically and genetically very similar to P. websteri from Australia, China, Japan, and the east, gulf and west coasts of the USA. This confirms the presence of P. websteri in South Africa, making this the second most widespread polydorin pest of aquaculture known. Understanding the full distribution range of the species will help to better understand its global route of invasion and consequently assist with preventing or at least minimising further spread. Polydora websteri increases the number of polydorin pests in South Africa to seven.

BACKGROUND:Common names are frequently used inconsistently for marine annelid species used as bait in the peer-reviewed literature, field guides and legislative material. The taxonomy of many such species based on morphology only also ignores cryptic divergences not yet detected. Such inconsistencies hamper effective management of marine annelids, especially as fishing for recreation and subsistence is increasing. This study investigates the scale of the problem by studying the use and names of bait marine annelids in the Western Cape Province of South Africa.METHODS:Fifteen recreational and six subsistence fishers at 12 popular fishing sites in the Western Cape Province donated 194 worms which they identified by common name. Worms were assigned scientific names according to a standard identification key for polychaetes from South Africa, and mitochondrial cytochrome oxidase I (COI) amplified and sequenced.RESULTS:This study identified 11 nominal species known by 10 common names, in the families Siphonosomatidae, Arenicolidae, Sabellaridae, Lumbrineridae, Eunicidae, Onuphidae and Nereididae. Cryptic diversity was investigated through employing mitochondrial COI sequences and these data will facilitate future identifications among widely distributed species. Several species (Siphonosoma dayi, Abarenicola gilchristi, Scoletoma species, Marphysa corallina, Lysidice natalensis, Heptaceras quinquedens, Perinereis latipalpa) are reported as bait for the first time, and while the names blood- and moonshineworms were consistently applied to members of Arenicolidae and Onuphidae, respectively, coralworm was applied to members of Sabellaridae and Nereididae. Analysis of COI sequences supported morphological investigations that revealed the presence of two taxonomic units each for specimens initially identified as Gunnarea gaimardi and Scoletoma tetraura according to identification keys. Similarly, sequences for Scoletoma species and Lysidice natalensis generated in this study do not match those from specimens in China and India, respectively. Further research is required to resolve the species complexes detected and also to refine the use of names by fishermen over a wider geographic range.

In the Western Indian Ocean (WIO), more than 76 records from peer-reviewed and grey literature identified approximately 60 invertebrate taxa harvested for bait and food. The most diverse phyla were Mollusca, followed by Arthropoda and Annelida, with few records of Porifera, Nemertea and Echinodermata. Importance of each phylum differs according to country, with arthropods (Upogebia africana and Kraussillichirus kraussi), and annelids (Marphysa mossambica) being most important in South Africa and Kenya, respectively. Of the taxa utilised, only 42 are reliably identified to species level, suggesting that the diversity of species utilised in the region is greatly underestimated. Most of the data on biology and exploitation were for species from South Africa. Less data were available from Kenya with minimal to none being available from the remaining WIO countries. This limits the understanding of biology and trends in exploitation of most bait taxa, and consequently information required for developing national and regional management policies. Bait management guidelines are available only for South Africa, but require updating in view of changes in use of bait resources. We recommend the development of coordinated multidisciplinary, multicountry research aimed at increasing data and information to feed into policy development and support national and regional bait resource management.

In this study we report a new record of a cryptogenic polychaete from southern Africa. The species was found inhabiting sand tubes in intertidal sand flats in the Knysna Estuary on the southern coast of South Africa. Morphological comparisons using light and scanning electron microscopy showed extensive taxonomic similarities with Dipolydora socialis described from other localities and from museum vouchers. In addition, 18S rRNA and COI barcodes were generated for the species. Genetic analysis of the assembled polydorid dataset corroborated the morphological data in delineating the species as a taxonomic unit with >99% genetic similarity to available sequences of D. socialis in the GenBank database. Dipolydora socialis has been reported as having a widespread distribution, and since it can reside within tubes associated with fouling communities or as a shell borer, several vectors may have been responsible for its global spread and introduction to southern Africa. Finally, considering the many cryptic complexes that are currently being uncovered within polychaetes, including spionids, future taxonomic studies should incorporate additional genetic data from other regions of the world to determine whether D. socialis may also be part of a larger species complex.

Abstract Moonshine worms are a popular bait species used for fishing. The taxon was not detected during surveys of the macrobenthos conducted in Knysna in the 1940s and 1990s, and was first reported as a harvested bait species in the mid-2000s, suggesting that it appeared for the first time in the estuary in the last three decades. A previous molecular analysis identified the worms as Diopatra aciculata, a species first described from Australia. This study provides an updated detailed morphological description of D. aciculata in South Africa to facilitate future identifications and also investigates the species' distribution and population size in the Knysna Estuary. Specimens were examined by scanning electron, stereo- and compound microscopes. Diopatra aciculata has tubes that protrude from the sediment in sandy areas, often decorated with algae and shell fragments; a large body size, up to 600 mm long and 11.5 mm wide. It has 10–18 rings on ceratophores; 5–10 teeth on pectinate chaetae; uni- and bidentate pseudo-compound falcigers and dorsal cirri approximately as long as branchiae. Diopatra aciculata was detected up to 12 km from the mouth of the Knysna Estuary with densities measured at 18 sampled sites. Statistical analysis retrieved high and low density groups that were significantly different from one another (Kruskal-Wallis H(14, 800) = 376.55; P = 0.01), but distribution of high density sites was patchy. We estimate that the population comprises 20–24 million individuals. Given the size of individual worms and the population estimate, this species can be expected to have significant ecological impacts in the estuary.

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, Marphysa sanguinea 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 M. sanguinea are now known as Marphysa elityeni Lewis & Karageorgopoulos, 2008. Of the six Marphysa 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 M. elityeni and investigated the presence of the widespread species Marphysa macintoshi Crossland, 1903 and Marphysa depressa Schmarda, 1861 in South Africa using morphological and molecular data. Our results reveal that M. elityeni is a junior synonym of Marphysa haemasoma, a species previously described from South Africa which is herein reinstated as a valid species. Both M. macintoshi and M. depressa are not present in South Africa and their status as being distributed worldwide deserves further investigation. Marphysa durbanensis Day, 1934 and the new species described here, M. sherlockae n. sp., had been misidentified as M. macintoshi and M. depressa respectively. Thus, the number of Marphysa 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.

The perceived cosmopolitanism of polychaete worms could be an artefact of historical factors such as poor original species descriptions, lack of type material and the European taxonomic bias, to name a few. Thus, it is possible that several cosmopolitan species hide complexes of cryptic and pseudocryptic species. Two putative cosmopolitan species, Platynereis dumerilii and Platynereis australis, collected in South Africa were investigated here (1) to determine whether the South African taxa are conspecific with the morphologically identical taxa from France and New Zealand (the respective type localities of P. dumerilii and P. australis), (2) to compare the South African species morphometrically to determine whether their morphological characters are reliable enough to separate them, and (3) to investigate whether these species have geographically structured populations along the coast of South Africa. Molecular data (COI and ITS1) confirm that P. dumerilii and P. australis do not occur in South Africa. Instead, the South African taxon formerly thought to be Platynereis dumerilii is new and is described here as Platynereis entshonae, sp. nov.; the identity of the other South African species is currently unresolved and is treated here as Platynereis sp. Surprisingly, Platynereis massiliensis (type locality: Marseilles) nested within the South African Platynereissp. clade but, since it is part of a cryptic species complex in the Mediterranean, the name is considered doubtful. Morphological characters traditionally used to define these South African Platynereis species are not reliable as predefined morphological groupings do not match phylogenetic clades and principal component scores revealed no separation in morphological characters that could distinguish between them. Haplotype networks and phylogenetic trees revealed that P. entshonae, sp. nov. and Platynereis sp. have geographically structured populations along the South African coast. http://zoobank.org/urn:lsid:zoobank.org:pub:6E36A210-9E48-430F-8A93-EDC27F0C5631