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Freshwater ecosystems are the most threatened on Earth, with many species facing extinction. The Clanwilliam sandfish (Labeo seeberi) is South Africa's most threatened migratory freshwater fish and is endemic to the Olifants–Doring River system in the Cape Fold Ecoregion. Non‐native fish predation and river desiccation have caused a recruitment bottleneck, severely compromising juvenile survival and resulting in a declining population of aging sandfish. The Saving Sandfish Project launched an emergency head‐start intervention in 2020 to reduce extinction risk. We (1) rescued juvenile sandfish from drying pools in a key spawning tributary (the Biedouw River); (2) relocated them to 6 off‐stream reservoirs; and (3) released reservoir‐reared sandfish back into their natal river once large enough to evade non‐native fish predation. Here, we estimate survival in the reservoir environment, evaluate return rates relative to wild run size, and assess the probability of return based on conditions at release. Between 2020 and 2022, we stocked 33,391 juvenile sandfish into the 6 reservoirs. After 1 year, the estimated survival rate at one reservoir was 0.679 (range based on 95% CI: 0.385–0.973). Release and return results are presented only for the first (2020) rescue cohort. In 2021, we released 1277 sandfish from 2 reservoirs into the Biedouw River, comprising 16.6% of the 2020 rescue cohort. Mean size at release was 169 mm (SE 0.6) total length. Of those released, 994 were PIT‐tagged. A total of 77 PIT‐tagged sandfish were recorded during the 2022 spawning migration—a return rate of 7.7% of tagged releases in the first year of returns. Size of fish and distance from the Doring River at release were significant predictors of return probability, with larger fish released further from the Doring experiencing a higher probability of return. This program serves as a model for the conservation of freshwater fish where there is an imminent and high risk of extinction. [ABSTRACT FROM AUTHOR]

Recent phylogeographic studies of poorly-dispersing coastal invertebrates in highly biodiverse regions have led to the discovery of high levels of cryptic diversity and complex phylogeographic patterns that suggest isolation, geological, and ecological processes have shaped their biodiversity. Studies of southern African coastal invertebrates have uncovered cryptic diversity for various taxa and phylogeographic patterns that, although sharing some similarities across taxa, do differ. These findings underscore the need for additional studies to better understand the biodiversity levels, distributional patterns, and processes responsible for producing coastal biodiversity in that region. The coastal isopod Deto echinata is of particular interest, as its complex taxonomic history, poor dispersal capabilities, and broad geographic distribution suggest the potential for cryptic diversity. We use mitochondrial and nuclear sequences to characterize D. echinata individuals from localities ranging from northern Namibia to Glentana, about 2,500 km along the coastline on the south coast of South Africa. These are used to assess whether D. echinata harbors cryptic genetic diversity and whether phylogeographic distributional patterns correlate with those previously documented for other coastal isopods in the region. Analysis of mitochondrial and nuclear sequences revealed two deeply-divergent lineages that exhibit a distributional break in the Cape Peninsula region. These findings suggest D. echinata is a cryptic species complex in need of taxonomic revision and highlight the need for further taxonomic and phylogeographic studies of similarly poorly-dispersing coastal invertebrates in southern Africa. [ABSTRACT FROM AUTHOR]

In South Africa, freshwater habitats are among the most threatened ecosystems, and freshwater fishes are the most threatened species group. Understanding patterns in freshwater fish diversity, threat, invasion, and protection status are vital for their management. However, few studies have undertaken such analyses at ecologically and politically appropriate spatial scales, largely because of limited access to comprehensive biodiversity data sets. Access to freshwater fish data for South Africa has recently improved through the advent of the Freshwater Biodiversity Information System (FBIS). We used occurrence records downloaded from the FBIS to evaluate spatial patterns in distribution, diversity, threat, invasion, and protection status of freshwater fishes in South Africa. Results show that record density varies spatially, at both primary catchment and provincial scales. The diversity of freshwater fishes also varied spatially: native species hotspots were identified at a provincial level in the Limpopo, Mpumalanga, and KwaZulu-Natal provinces; endemic species hotspots were identified in the Western Cape; and threatened species hotspots in the Western Cape, Mpumalanga, Eastern Cape, and KwaZulu-Natal. Non-native species distributions mirrored threatened species hotspots in the Western Cape, Mpumalanga, Eastern Cape, and KwaZulu-Natal. Some 47% of threatened species records fell outside of protected areas, and 38% of non-native species records fell within protected areas. Concerningly, 58% of the distribution ranges of threatened species were invaded by non-native species. [ABSTRACT FROM AUTHOR]

Freshwater fishes are recognised as South Africa's most threatened species group. Reliable, long-term data on fish occurrence records are critical for effectively managing and conserving these species. A comprehensive freshwater fish dataset was compiled and uploaded to the Freshwater Biodiversity Information System (FBIS, freshwaterbiodiversity.org), comprising all available records of formally described freshwater fish species occurring in South Africa. An 18-month historic-data collation effort resulted in the accrual of 35 955 new records of freshwater fish from South Africa spanning 194 years (1828-2022), that have since been uploaded to the Global Biodiversity Information Facility (GBIF). Together with pre-existing GBIF records (24 861), a total of 60 837 freshwater fish records are thus now available for South Africa. The data show a marked decline in the number of native fish occurrence records over the last decade. Conversely, the number of occurrences for non-native fishes increased over the past three decades. A data breakdown is provided for each of South Africa's nine provinces including total number of records, and the numbers of native, non-native, endemic and threatened species. These data provide a much-needed update of the known status and distribution of freshwater fishes in the country. [ABSTRACT FROM AUTHOR]

The tanaid Pagurapseudes dentatus was described from a male collected from the intertidal zone at False Bay, South Africa. The description was poorly illustrated, incomplete, did not describe the female or juvenile stages, and gave no information on its habitat. The species was rediscovered and found to be locally abundant at locations in South Africa, where it inhabits vacant gastropod shells. We redescribe P. dentatus by fully illustrating and describing its morphological characters, including the copulatory female and manca II stages. Pagurapseudes dentatus differs from similar species by a long seta on the basis of the characteristically elongated pereopod-1, as well as its singular distal pectinate setae on the propodus and adjacent to the dactylus of pereopod 6. Nano-CT scanning was used to illustrate and document the unusual mode of occupation of empty gastropod shells by the species. It was found (N = 139) occupying shells of 19 gastropod species from 10 different genera, occurring most abundantly in shells of Tricolia Risso, 1826, Burnupena Iredale, 1918, Assiminea Fleming, 1828, and Gibbula Risso, 1826. It forms dense populations under intertidal boulders, where it co-occurs with, and may compete for empty shells, with at least two common species of hermit crabs. [ABSTRACT FROM AUTHOR]

The parapagurid hermit crabs Sympagurus dimorphus (Studer, 1883) and Parapagurus bouvieri (Stebbing, 1910) form dominant components of South African deeper‐water benthic invertebrate communities and, as adults, forego the use of "traditional" gastropod shells in favour of symbiotically associated Epizoanthus carcinoecia. A total of 1,122 adult S. dimorphus and 549 adult P. bouvieri derived from demersal research trawl surveys were examined to investigate parameters of population structure, carcinoecia association and morphology. S. dimorphus had a female‐biased sex ratio of 1:1.5, and P. bouvieri an equal sex ratio of 1:1. The proportion of males of both species increased with cephalothoracic shield length (CL). The lengths of the major right chelipeds of both S. dimorphus males and females, and P. bouvieri males were positively allometric, and negatively allometric in P. bouvieri females. All P. bouvieri inhabited carcinoecia, while 3.39% (n = 38) of S. dimorphus specimens occupied gastropod shells. There was a positive relationship between S. dimorphus CL and rate of gastropod shell occupation (r2 = 0.96). In S. dimorphus, number of zoanthid polyps forming the carcinoecia pseudoshell increased with both total shell volume (R2 = 0.73) and colony height (R2 = 0.61), but no such relationships were found for P. bouvieri. Euspira napus was the most common original shell around which carcinoecia developed in both S. dimorphus (45.45%) and P. bouvieri (39.00%). We speculate that these hermit species exist along an evolutionary continuum of carcinoecia use. Sympagurus dimorphus retains the ability to occupy both gastropod shells and pseudoshells and, like most other hermit crabs, continue to use shells/carcinoecia as shelters to protect the entire body. In contrast, adult P. bouvieri appear to be totally reliant on carcinoecia, which they use more as a brood pouch covering only the abdomen, rather than as a shelter into which they can fully retract to escape predation. [ABSTRACT FROM AUTHOR]

The herbivorous amphipod Sunamphitoe roberta n. sp. is described from the canopy of kelp beds in False Bay, South Africa. The new species has unusual habits, small family groups burrowing directly into the margins of the swollen primary fronds of the kelp Ecklonia maxima (Osbeck) Papenfuss, 1940. Morphologically, the new species is best distinguished from other species of Sunamphitoe by strong rows of dorsal spines on the outer rami of uropods 1 and 2. These spine rows appear to be employed as 'drill-bits' to excavate kelp tissue and create the burrows. Damage to hosts does not appear to be fatal, but requires further investigation. [ABSTRACT FROM AUTHOR]

The first records of the maritime earwig Anisolabis maritima from South Africa are reported. The species was first discovered in 2015 in the upper intertidal zone of an artificial rubble causeway at Port Shepstone, on the east coast of South Africa, where it appears to feed on driftline isopods and amphipods. The study site operated briefly as a harbour from 1880-1902, suggesting that this introduction took place via shipping at that time and has remained undetected for more than a century. [ABSTRACT FROM AUTHOR]

A new species of hermit crab, Pagurus fraserorum n. sp. (family Paguridae) is described from rocky subtidal reefs off KwaZulu-Natal, South Africa, and illustrated using both conventional drawings and colour photographs, and via three-dimensional (3D) X-ray micro-computed tomography (μCT). Because of the limitation μCT has in detecting very fine and soft structures, a novel approach of manually drawing setation and spinulation onto the two-dimensional images of the 3D visualizations was used to illustrate the pereopods. In addition, an interactive figure and rotation movie clips in the supplement section complement the species description, and the 3D raw data of the 3D type data are downloadable from the Gigascience Database repository. The new species is the sixth species of Pagurus Fabricius, 1775 reported from South Africa and is closely allied to the Indo-Pacific P. boriaustraliensis Morgen, 1990 and P. pitagsaleei McLaughlin, 2002, from which it differs by its shorter ocular peduncles, by the armature of the carpus of the right cheliped, and also in colouration. This study presents the first description of a hermit crab in which a majority of taxonomic details are illustrated through 3D volume-rendered illustrations. In addition, colour photographs and COI molecular barcodes are provided, and the latter compared to COI sequences of specimens from Western Australia previously identified as P. boriaustraliensis and of specimens of P. pitagsaleei from Taiwan, as well as to three additional South African members of the genus. The South African taxon was confirmed to be genetically distinct from all species tested. [ABSTRACT FROM AUTHOR]

The porcelain crab Porcellana africana Chace, 1956, a species native to NW Africa, between Western Sahara and Senegal, is reported from Saldanha Bay, South Africa, and both morphological evidence and DNA analysis are used to confirm its identity. The taxonomic history of P. africana is summarized, and the taxonomic implications of the DNA analysis are discussed. The observations that the South African population appeared suddenly and that it is located in and around a major international harbour, strongly suggest that it represents a recent shipping introduction. Porcellana africana was first detected at a single site within Saldanha Bay in 2012, but by 2016 was abundant under intertidal boulders and within beds of the invasive mussel Mytilus galloprovincialis across most of the Bay. It remains absent along the adjacent oceanic coastline and in other regional harbours, but these should be monitored to detect any subsequent range expansion. [ABSTRACT FROM AUTHOR]

Recent phylogeographic studies along the coastline of southern Africa have uncovered cryptic diversity in several coastal invertebrates, including direct developing crustaceans in the superorder Peracarida. These findings indicating the possible existence of additional cryptic diversity in other yet to be studied peracarids, particularly those known to harbor said cryptic diversity in other regions of the world. Isopods in the genus Ligia are one such taxon. They inhabit patchy rocky beaches, are direct developers, avoid the open water, and exhibit other biological traits that severely constrain their dispersal potential (e.g., poor desiccation resistance). These traits are thought to have led to long- term isolation of populations, and allopatric diversification in Ligia species around the world; however, Ligia species in southern Africa, where three endemic Ligia species of uncertain validity are known to exist, remain unstudied to date. In this study, we used mitochondrial and nuclear markers to characterize Ligia collected in 18 localities from Namibia to the KwaZulu-Natal region of South Africa. We report the presence of cryptic lineages within Ligia species in the region that suggest the need for taxonomic reevaluation of these isopod species. [ABSTRACT FROM AUTHOR]

Background: Along with the conventional deposition of physical types at natural history museums, the deposition of 3-dimensional (3D) image data has been proposed for rare and valuable museum specimens, such as irreplaceable type material. Findings: Micro computed tomography (µCT) scan data of 5 hermit crab species from South Africa, including rare specimens and type material, depicted main identification characteristics of calcified body parts. However, low-image contrasts, especially in larger (>50 mm total length) specimens, did not allow sufficient 3D reconstructions of weakly calcified and fine characteristics, such as soft tissue of the pleon, mouthparts, gills, and setation. Reconstructions of soft tissue were sometimes possible, depending on individual sample and scanning characteristics. The raw data of seven scans are publicly available for download from the GigaDB repository. Conclusions: Calcified body parts visualized from µCT data can aid taxonomic validation and provide additional, virtual deposition of rare specimens. The use of a nondestructive, nonstaining µCT approach for taxonomy, reconstructions of soft tissue structures, microscopic spines, and setae depend on species characteristics. Constrained to these limitations, the presented dataset can be used for future morphological studies. However, our virtual specimens will be most valuable to taxonomists who can download a digital avatar for 3D examination. Simultaneously, in the event of physical damage to or loss of the original physical specimen, this dataset serves as a vital insurance policy. [ABSTRACT FROM AUTHOR]

A long-term sightings and photographic identification (photo-ID) database documented the inter-annual and monthly trends in white shark ( Carcharodon carcharias) sightings, sex ratios and life-history stages at Seal Island, False Bay, South Africa, over the period 2004-2012. A total of 1105 sightings were recorded during 171 scientific surveys incorporating 577 h of observation (annual mean 64.10 h, range 23.71-178.69 h). The mean annual sighting rate was 1.87 (range 0.90-3.19) sharks per hour and sighting rates declined over the nine-year study period. It is unknown whether the decline resulted from an actual population decline, or was due to changes in shark distribution or environmental conditions, but it highlights the need for ongoing monitoring at this site. The overall sex ratio was 1.0: 1.0: 2.3 for male: female: unsexed sharks, respectively. Of the 1105 sightings, 39% ( n = 433) were photo-ID'd, representing 303 individual sharks (112: 111: 80, male: female: unsexed) and 130 resightings. Of the 303 photo-ID'd sharks, 71% were sighted in a single year only, indicative of transient behaviour. Of the 29% of sharks that were resighted in more than one year, 65% were resighted in the following year, indicating site fidelity to Seal Island, whereas 35% skipped one or more years between encounters, indicative of a temporary absence. The majority (60%) of the photo-ID'd sharks were immature, 32% were subadult and only 8% were mature. No young-of-the-year sharks and few adults were recorded, indicating that Seal Island is not an adult aggregation site, nor a pupping or nursery area, but rather is best described as a seasonal feeding ground. Large females were rarely resighted again after they approached length-at-maturity (≥450 cm TL), whereas some adult males were recorded consistently across years. The emigration of subadult female sharks approaching maturity from Seal Island, combined with the small number of mature sharks of both sexes reported from any South African location, indicate that adult aggregation sites, and thus areas of reproductive importance, still remain unknown. [ABSTRACT FROM AUTHOR]

Faunistic studies in sublittoral and littoral marine habitats on the Cape Peninsula, South Africa, have yielded three new species belonging to the genus Heteromysis, subgenus Heteromysis: H. cancelli sp. n. associated with the diogenid hermit crab Cancellus macrothrix Stebbing, 1924, and H. fosteri sp. n. extracted from 'empty' urchin and gastropod shells. The first documented mysid-cephalopod association is reported for H. octopodis sp. n. which was found in dens occupied by Octopus vulgaris Cuvier, 1797, but was also captured from tide pools. The three new species differ from previously known E. Atlantic species, among other characters, by a single spine on the endopods of uropods in combination with large cornea and absence of median sternal processes on thoracic somites. They are also characterized by a white stripe along the dorso-lateral terminal margin of the eyestalks in living specimens. The new species appear quite similar to each other, but are distinguished by different depths of the telson cleft, different distributions of spines on the lateral margins of the telson, different numbers of segments on thoracic endopod 4, and by differently modified setae on the carpus of the third thoracic endopod, as well as on the carpopropodus of the fourth endopod. An updated key to the species of Heteromysis known from the E. Atlantic is given. [ABSTRACT FROM AUTHOR]

Background: There is no comprehensive inventory and analysis of the composition, distribution, origin and rate of introduction of the alien fauna of South Africa. Objectives: To provide such an analysis to facilitate effective ecological management, and compile a comprehensive inventory of introduced animal species across major habitats. Methods: All available databases and references were used to compile the inventory, forming the basis of subsequent analyses. A graduated map was produced to identify concentrations of alien species. Results: Of the 571 alien animal species analysed, insects comprised the largest component (53%, 300 species), followed by molluscs (9%, 51 species), annelids (8%, 48 species), arachnids (7%, 41 species), vertebrates (7%, 41 species) and crustaceans (6%, 36 species). Vertebrate introductions (88%) were largely intentional, whereas 84% of invertebrate introductions were unintentional Conclusions: Almost all marine and most terrestrial alien species were accidentally introduced, whereas freshwater introductions were almost entirely intentional. Some 13% had not spread significantly, 16% had spread significantly and 71% had become fully invasive. Vertebrate introductions virtually ceased after the 1950s, but rate of introduction of invertebrates remained linear. The overall rate of species accumulation was fairly low until 1880, but accelerated sharply thereafter. Most terrestrial alien species originated from Europe (28.6%) and Asia (25.0%) and the lowest proportion (6.1%) from Africa. Freshwater introductions largely originated from the Americas, with few from Africa. The most invaded areas were around Cape Town, (up to 162 introduced species/half-degree grid cell), followed by Gauteng and Durban. [ABSTRACT FROM AUTHOR]