African Zoology

Editorial

Carol A Simon — 2025-05-28

No abstract.

Redescription of Arabella iricolor (Montagu, 1804) with descriptions of two new species from the United Kingdom and South Africa

T Darbyshire — 2025-05-28

Arabella iricolor (Montagu, 1804) was described with no diagnostic information for the characters used today to distinguish species within the genus. An updated description, together with genetic data, is provided using the holotype in conjunction with additional specimens collected at or near the type locality, to facilitate comparative analysis of other Arabella species and improve taxonomy within the genus. Arabella iricolor can be distinguished primarily through the long notopodial cirri that reach to or beyond the prechaetal lobes on chaetigers 1–9, in combination with unidentate maxilla I on both sides, four short digitiform pygidial cirri and gradually tapering ventralmost chaetae. The updated description and molecular information enabled the identification of a new species co-habiting with A. iricolor at the type locality and elsewhere. The new species, Arabella ampulliformis sp. nov., is characterised by two lateral pygidial lobes that extend into short cirri, appearing ampulliform in lateral view, in combination with a bifid left maxilla I, short left and long right maxilla II, short notopodial cirri and gradually tapering ventralmost chaetae. A new species from South Africa is also described, Arabella umgazanae sp. nov., distinguished through a bifid left maxilla I, short left and long right maxilla II, short notopodial cirri, two large lateral pygidial lobes and gradually tapering ventralmost chaetae along with additional characters relating to the chaetae, mandibles and maxillary apparatus. Problems surrounding the identification of Arabella species in South Africa are discussed in conjunction with details of the other species reported from the region.

Untangling the Magelonidae (Annelida: Polychaeta) of southern Africa, including the description of a new species

Kate Mortimer — 2025-05-28

‘A monograph on the Polychaeta of Southern Africa’ by J. H. Day, published in 1967 and covering over 700 species, was considered an essential reference text for marine biologists. Nonetheless, despite the major contribution it has made, we now know that the biodiversity of Polychaeta (commonly known as bristleworms) in southern Africa has been underestimated by more than 500 species. As one of the top 20 polychaete families highlighted as requiring revision in southern Africa, direct observation of magelonids in the collections of Iziko Museums of South Africa and Natural History Museum, London identified by John Day, and additional material has been carried out. This has revealed that the original description of Magelona capensis was based on two species. Consequently, an additional redescription of the holotype of M. capensis is provided herein, and the additional material is described as Magelona ekapa sp. nov. The new species shares similarities with eight species comprising the ‘Magelona pitelkai group’, which is further discussed. A redescription of M. cincta is also provided based on the holotype and freshly collected material. A specimen from Morrumbene Estuary, southern Mozambique, originally identified as M. cincta likely represents an undescribed species: images and a description are provided here, but the species will remain undescribed until further material becomes available. A dichotomous indentification key and a table of characters is provided for all known southern African species of the Magelonidae.

Lumbrineris magalhaensis Kinberg, 1865 (Annelida: Lumbrineridae) revealed as two indigenous species in South Africa

Adri van Niekerk — 2025-05-28

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.

A new species of Malacoceros (Annelida, Polychaeta, Canalipalpata, Spionidae) from urban waters in Gabon

Nicolas Lavesque — 2025-05-28

A new species of Malacoceros is described from estuarine equatorial waters in Libreville (Gabon, West Africa). During a recent environmental study aimed to assess the urban impact on an estuarine ecosystem near Libreville, the collection of sediment samples from the area was undertaken. The local invertebrate macrofauna had not been previously well studied, and to document the biodiversity, specimens were examined in more detail. A new species of Malacoceros was discovered, occurring in mangrove areas. The new species is described and illustrated in detail, and information on three molecular markers was retrieved and partially used for species delimitation analysis. The new species resembles Malacoceros indicus (Fauvel 1928) described from India but is easily distinguished by a very conspicuous morphological character, the presence of 7–11 large tubercles along the anterior margin of the prostomium. The presence of such conspicuous tubercles has never been observed before in Malacoceros. Maximum likelihood trees for species of Malacoceros and the close genera of Rhynchospio, for which we have data, are also provided. The suitability of characters used for species delimitation in Malacoceros is discussed.

Refining the morphological characteristics of Dipolydora capensis (Day, 1955) and Dipolydora goreensis (Augener, 1918) (Annelida: Polychaeta: Spionidae) from Atlantic African waters

Vasily I Radashevsky — 2025-05-28

Together with Syllidae, Nereididae and Eunicidae, Spionidae is one of the four more speciose families of polychaete annelids in southern Africa, comprising 25% of the known species and 53–85% of the unresolved cosmopolitans. Among southern African spionids, the genus Dipolydora Verrill, 1881 particularly requires further revision and, in this paper, we contribute by refining the morphological characteristics of D. capensis (Day, 1955) and D. goreensis (Augener, 1918). Neither species has been redescribed since their original description and are currently difficult to distinguish and identify. Therefore, our study provides additional morphological details based on examining type specimens and newly collected materials from South Africa and the Republic of Congo.

Morphological and molecular investigation of Scolelepis agilis (Verrill, 1873) (Annelida: Spionidae) from beaches of the Atlantic coast of North America

Corey Bonavia — 2025-05-28

Polychaete worms of the genus Scolelepis are one of the most abundant members of beach ecosystems worldwide. Along the Atlantic coast of North America, specimens of Scolelepis inhabiting high-energy beaches have long been erroneously identified as the European species Scolelepis squamata (O.F. Müller, 1806). In this study, we examined specimens of Scolelepis collected from Massachusetts to Virginia, finding they match Scolelepis agilis (Verrill, 1873), originally described from beaches in New Jersey. Scolelepis agilis can be most easily distinguished from S. squamata based on differences in palp ciliary pattern, morphology of neuropodial lamellae, and the quantity and start of both notopodial and neuropodial hooded hooks. Live specimens of S. agilis collected from New York were also examined to provide data on their reproduction and morphometric analyses. In addition, molecular data (18S, 28S rRNA, cytochrome c oxidase I and 16S rRNA) showed that specimens of S. agilis from the north to mid-Atlantic coast formed a monophyletic group (p-distance ≤ 0.004 for MA, RI, NY and VA populations) and were distinct from S. squamata (p-distance ≥ 0.196 (0.03 SE)). The molecular data also suggest the presence of several misidentified or undescribed species of Scolelepis, highlighting the need for additional taxonomic work on the genus from these localities as well as others (e.g. South Africa) where the worms have been incorrectly identified as S. squamata. A key to species of Scolelepis from the east coast of the United States is provided and a lectotype and paralectotypes for S. agilis are herein designated.

Review of Arctic and Pacific Marenzelleria (Annelida: Spionidae), with new records and comments on Spio gorbunovi Averincev, 1990

Vasily I Radashevsky — 2025-05-28

Here we summarise and map available records of the spionid polychaetes Marenzelleria spp. from the Arctic and Pacific Oceans based on morphology and analysis of sequences of five gene fragments (COI, 16S, 18S, 28S and Histone 3). We define for the first time the complex of M. arctia species, including M. arctia-1 from the Baltic, Barents and White Seas, and M. arctia-2 from the Kara Sea east to the Bering Strait. The relationships of these groups to M. arctia (Chamberlin, 1920) from the type locality of this species in the Beaufort Sea remain unclear. We report a new record of M. neglecta Sikorski and Bick, 2004 from Oregon, USA, and consider the presence of this species in the Canadian Arctic and USA Pacific due to introductions for which routes and vectors remain unclear. We also report M. wireni Augener, 1913 for the first time from Arctic Canada (Nunavut). Molecular analysis showed a genetic similarity of the Canadian specimens with worms identified as M. wireni from the Greenland and Laptev Seas. We expect that a future phylogenetic analysis of the relationships of the Asian population, which is currently referred to M. arctia and has never been studied genetically, will shed light on the origin and evolution of the entire genus. Study of the type specimens of Spio gorbunovi Averincev, 1990, described from the Laptev Sea, revealed that this species is a junior synonym of M. arctia, rather than M. wireni as proposed by previous authors.

Colonisation patterns and reef growth of the invasive serpulid Ficopomatus enigmaticus in a Greek coastal lagoon

Athanasia-Violeta Ntzoumani — 2025-05-28

The reef-building serpulid polychaete Ficopomatus enigmaticus is an invasive species in brackish waters in tropical and temperate zones worldwide and often has massive impacts on ecosystems and anthropogenic activities. In Prokopos Lagoon in Greece, the species has constructed large reefs over the past few decades which occupy a large area of the lagoon. In this study, we used high-resolution aerial photography to map the distribution of these reefs, and conducted a one-year field survey to investigate settlement and growth parameters, including abundance, biomass and body length, using artificial settlement panels. We correlated our findings with physicochemical measurements, specifically focusing on temperature, salinity and dissolved oxygen. Salinity exhibited marked and rapid fluctuations, ranging from less than 2 to over 42 Practical Salinity Units (PSU). These variations did not affect the adult population, but settlement only occurred at salinities above approximately 10 PSU and only when water temperatures surpassed 18–20°C. Settlement was reduced when temperatures were high (> 28 °C) but was not affected by high salinity. The maximum abundance measured was 880 000 individuals m⁻², and reefs attained a weight of 18 kg m⁻² in 11 months. This study contributes further to understanding the species’ environmental tolerances and life cycle, which in turn may help to design future management measures.

Arenicolidae (Annelida) in Norwegian waters: species occurrence, bathymetric distribution and identification of juvenile specimens

Marthe R Dille — 2025-05-28

The two species of Arenicolidae, Arenicola marina and Arenicolides ecaudata, are common along the Norwegian coast. Juveniles and anterior fragments are often encountered when grab sampling, making traditional morphological characteristics insufficient for species identification. This study examined the robustness of the characteristics and development of branchiae in juvenile specimens of Arenicolides ecaudata (n = 109) and Arenicola (n = 44) (A. marina and Arenicola sp.) and additional specimens to assess geographic and bathymetric distribution. Neuropodia were discovered to be efficient in distinguishing the species. Branchiae of A. ecaudata appear when specimens measure between 7–13 mm, while in A. marina they appear in specimens measuring between 3–5 mm. The ring formula in anterior chaetigers is a key characteristic in differentiating between Arenicola species. This characteristic alone is insufficient for reliable species identifications, as study findings corroborated error rates in identification based on the ring formula. The bathymetric range of both species has increased considerably. Arenicola marina was documented at 194 m depth and A. ecaudata at 387 m depth. DNA barcodes with the cytochrome c oxidase subunit I (COI) gene were produced for three specimens of Arenicolides ecaudata, representing the first publicly available COI barcode sequences for this species. Five specimens of Arenicola marina, with similar sequences to specimens from other north-eastern Atlantic localities were also barcoded in BOLDsystems.

Serpulid diversity of coralligenous build-ups in the southwestern Ionian Sea

Rossana Sanfilippo — 2025-05-28

Coralligenous build-ups in the Ionian Sea off southeastern Sicily, Italy, first discovered about 20 years ago, were recently studied as part of the Italian FISR project ‘CresciBluReef’. Coralligenous build-ups are a priority habitat in the Mediterranean Sea, yet their origin and species richness are still poorly known. In the studied area, calcareous algae constitute the primary framework of the concretions, and serpulid worms and other invertebrates contribute secondarily. Live and dead serpulid associations were sampled from four build-ups at a depth of 33–37 m. Thirty-five living species of Serpulidae were detected (12 Serpulinae, 15 Filograninae and 8 Spirorbinae), some of which were frequent and abundant. This greatly outnumbers the 7 species previously found at a single build-up in the same area, and the 10 species reported from nearby coralligenous concretions. All but two of the species were already known from the Mediterranean Sea, although eight of the species (three of which are still under description) are reported for the first time from the coralligenous biocoenosis. Our findings highlight that: (i) the serpulid species richness of the studied build-ups is higher than that known in other Mediterranean areas; (ii) the serpulid associations at the four build-ups are comparable in composition and structure, except for a slight reduction in numbers of individuals with depth; and (iii) at each build-up, serpulids are more abundant in the top part than in the bottom part of the concretions.

Diversity, distribution and knowledge gaps of Polychaeta on the continental shelf of southern Namibia

Amoré Malan — 2025-05-28

This study investigated the diversity, composition and distribution patterns of polychaete macrofauna inhabiting unconsolidated sediments on the continental shelf of southern Namibia. During the austral summer of 2021, 910 Van Veen grab samples were collected from 91 sites in water depths ranging between 43 and 146 m. All benthic macrofauna (> 1 mm) were extracted, identified, enumerated and weighed. Polychaetes were the most abundant taxon, equating to 66% of total abundance and 37% of total biomass. A total of 83 712 polychaete specimens comprising 112 species, 80 genera and 33 families were collected. Several taxa identified were listed as putative cosmopolitans (19 taxa) or have known wide local distributions (10 taxa). Voucher specimens were collected for DNA barcoding to improve reference sequence libraries for the region. Hierarchical cluster analyses using both abundance and biomass data were undertaken to determine spatial distribution patterns in polychaete communities. Both datasets yielded similar results with polychaete assemblages divided into inshore and offshore communities, that were further subdivided at a local scale. Investigation of physical and chemical drivers suggested that polychaete communities in southern Namibia are structured to varying degrees by water depth, latitude, sediment composition, redox potential and organic content. Deeper stations comprised the highest diversity of polychaeta fauna. Species adapted to hypoxic conditions (e.g. Sigambra parva, Pararionospio pinnata, Diopatra cf. monroi and Nepthys cf. hombergii) dominated an area known as the mudbelt, where organically enriched silts and clays originating from the Orange River are deposited on the mid-shelf between the 40 and 120 m isobaths.

Eunicid polychaete worms used as bait with particular reference to Australia, South Africa and France; the need for development of management plans based on their biology and ecology

Pat Hutchings — 2025-05-28

Worldwide, bait worms are collected for recreational and subsistence fishing, and fetch high prices in bait shops. While a variety of polychaete families are collected, we focus only on the “Marphysa” group (Family Eunicidae) occurring in rivers, estuaries and protected bays. We discuss the management strategies currently in place in Australia, South Africa and France, and we suggest that they are inadequate and fail to take into account Eunicid diversity and biology. While the reproductive strategies of only a few species have been investigated, they all exhibit very different strategies, and this must be taken into account when developing management and monitoring plans to ensure sustainable harvesting. Information is also needed on the impacts of collecting in these coastal habitats and their ecosystems that are increasingly being impacted by climate change. We also comment on the collection of the “Marphysa” group elsewhere in the world.

Gesa Hartmann-Schröder (1931–2022): A leading polychaete systematist

Dieter Fiege — 2025-05-28

No abstract.