Bambusina armata var. raciborskii is a rare desmid previously reported only from Brazil, Madagascar, and Thailand. This study documents its first record from continental Africa, based on material collected in central Angola. To date, only line drawings of this taxon have been published. In this paper the first photographs (both light-and scanning electron micrographs) are provided, emphasising the importance of this record. Cells from Angola closely resembled a smaller morphotype described from Madagascar. Distinguishing features from the nominate variety include divergent spines and swollen spine bases. This record extends the known distribution of the taxon to continental Africa, emphasising the importance of continued algal biodiversity surveys in underexplored regions, particularly Africa. Based on an intensive review of previously published literature and an analysis of morphological characteristics of B. armata var. raciborskii specimens from Angola, the raise of taxonomical status of B. armata var. raciborskii to species rank is proposed.

The first annotated checklist critically summarizes data published on the diversity of photosynthetic euglenids (Euglenophyceae, Euglenales: Euglenaceae and Phacaceae) from southern Africa. The nomenclature and synonymy used in this study are supplemented with the most recent taxonomic studies on particular genera, species or species complexes. In some cases, the specimens are re-identified using published illustrations. The checklist is supported with detailed information about each distributional record. An analysis of the literature showed that the Euglenophyceae flora in southern Africa has not been studied sufficiently and systematically. The number of recorded taxa consist of 154 taxa, including 50 in the genus Trachelomonas, 40 in the genus Phacus, 21 in genus Euglena, 17 in the genus Lepocinclis, 15 in the genus Strombomonas, three in the genus Monomorphina, two in each of the genera Colacium, Cryptoglena and Euglenaria, and one in each of the genera Cyclidiopsis and Euglenaformis.

Euglena sanguinea is a red-pigmented euglenid species known for producing the ichthyotoxin euglenophycin, which has been associated with fish mortalities in various freshwater systems. First reported in South Africa from the Kruger National Park in 2016, E. sanguinea has since spread rapidly across multiple provinces, forming persistent dense blooms in several freshwater bodies. This study documents its expanding range, with confirmed occurrences in dams, ponds, and wetlands in Limpopo, Mpumalanga, KwaZulu-Natal, and the Western Cape provinces. Microscopic investigations revealed consistently high densities of E. sanguinea dominating algal assemblages at all surveyed sites. Cells varied from green in shaded areas to bright red in full sun and showed typical metabolic shape variability. Water quality data recorded across four sites showed temperatures ranging from 21.6 to 31.1 degrees C, pH values between 7.23 and 8.0, electrical conductivity from 202 to 541 mu S cm-1, and total dissolved solids (TDS) between 102 and 271 mg l-1. The persistent and dense nature of these blooms highlights the potential ecological risk posed by E. sanguinea, especially under changing climatic conditions. The findings emphasise the urgent need for continued monitoring and the development of management strategies to mitigate potential impacts on aquatic ecosystems.

Ceratium rhomvoides Hickel is a freshwater photosynthetic dinoflagellate characterised by a robust theca having a blunt-tipped apical horn, one sharply pointed antapical horn and a short, but sharply pointed, postcingular horn. Its Kofoidian plate formula is 4', 6'', 6c, 6''', 2'''', with the fourth apical plate shortened, not reaching the apex. This species was found in freshwater samples from the Limpopo Province (South Africa). Although the species is reported frequently in the rest of the world, it was found only once in Africa, dating from more than a century ago. This study provides a detailed morphological and taxonomical description, distinguishing C. rhomvoides from closely related species, and correcting several historical taxonomical inaccuracies. High-resolution light and scanning electron microscope images of the species are presented, together with an updated record of its geographical distribution. The paper also presents the first record of its presence in southern Africa.

Two extremely rare and morphologically similar Gonatozygon species, namely G. dicranoaculeatum and G. chadefaudii, were previously recorded from only two geographical locations in the world. G. dicranoaculeatum was reported from Zambia and Australian billabongs, while G. chadefaudii was known from French Guiana and Australian billabongs. During June 2023, a Gonatozygon species was discovered in the upper reaches of the Okavango Delta, Botswana. This species had characteristics corresponding to both G. dicranoaculeatum and G. chadefaudii and can, therefore, be regarded as an intermediate between these two species. The main distinguishing characteristics between G. dicranoaculeatum and G. chadefaudii include the structure of the apices and chloroplasts, the presence of girdle bands and a slight median constriction, the cell length-to-width ratio, and the length of the spines on the surface. Gonatozygon cells from the Okavango Delta corresponded to G. dicranoaculeatum with regards to the chloroplast structure and the absence of a median constriction and girdle bands but were closer to G. chadefaudii in terms of their dilated apices and dimensions. Due to the discovery of cells with intermediate characteristics, the authors propose the merger of G. dicranoaculeatum and G. chadefaudii into a single taxon, namely G. dicranoaculeatum, as this name has priority. G. chadefaudii should then be transferred to a synonym of G. dicranoaculeatum.

Cosmarium knopkirri Levanets & Janse van Vuuren sp. nov. (Desmidiaceae, Zygnematophyceae) is a newly discovered desmid species collected from an inland wetland system near Palma, Cabo Delgado Province, northern Mozambique. The diagnostic features distinguishing it from other species in the genus include semicells decorated with four concentric, alternating rows consisting of well-developed, large granules. Granules of one row alternate approximately half of the inter-granule distance with respect to those in the next row. The apical circle consists of 6 finger-like granules, while 6, 8 and 10 hemispherical granules are present on the circles located subapical, median and adjacent to the sinus, respectively.

The history of Actinodontum lomaense has been marked by taxonomic revisions since its initial discovery in samples from Sierra Leone during 1984. The reassignment from the genus Docidium to the genus Actinodontum primarily resulted from pronounced morphological differences, including variations in cell size and shape, ornamentations on the cell wall, and the presence of conical teeth-like structures at the isthmus. This article reports on the discovery of A. lomaense in two locations in southern Africa, marking a significant expansion of the geographical distribution range of the genus, from the tropical regions of Sierra Leone to sub-tropical environments in South Africa and the Kingdom of Lesotho. Additionally, the preference of Actinodontum species for relatively high altitudes, observed in this study, confirms a biogeographical pattern characterising this genus. Cell dimensions recorded in the southern African samples slightly exceeded dimensions previously reported in the literature. As a result, an extention of the dimension ranges for this species is proposed. Findings presented in this article, along with physico-chemical variables measured in their habitat, contribute to our understanding of the ecological preferences and distribution patterns of A. lomaense. It also provides valuable insights into the biogeography of desmid species on the African continent.

This study investigates the morphology and distribution of infraspecific taxa of P. subcoronulatum. Research identified taxonomic issues and discrepancies in prior literature concerning morphological similarities among infraspecific taxa. The consolidation of two closely related taxa into a single variety, P. subcoronulatum var. majus, is suggested as a possible solution. This paper presents the first comprehensive morphological description (including dimensions) along with the first-ever images in the form of scanning electron micrographs of P. subcoronulatum var. majus. In addition, a new known geographical location for this taxon in the Okavango Delta, Botswana, expands its known distribution beyond previous records.

In this study, the authors report the discovery of a rare desmid species (Euastrum compereanum) in Mozambique and Namibia. The species was previously documented from only three African countries, namely Chad, Zambia, and Botswana. In a prior publication about desmids from Namibia a line drawing of this species was included, but the species was identified as E. platycerum var. eximium forma. This paper aims to address this taxonomic discrepancy, rectify the identification, and provide a definitive name assignment. Furthermore, our research expands the known distribution of E. compereanum by introducing a novel geographical record in Mozambique. Aside from the taxonomic correction and geographical distribution expansion, the paper offers the very first photographic documentation of its cellular morphology. Previous publications on this species solely relied on line drawings, making this publication a significant advancement in the understanding of its cell structure. (c) 2024 SAAB. Published by Elsevier B.V. All rights reserved.

The common freshwater dinoflagellate genus Peridinium includes the species P. gatunense and P. bipes, which are found globally. Despite forming a significant portion of algal communities, research on dinoflagellates in Africa is limited. This paper reports the first record of the presence of P. gatunense in South Africa, as well as the reappearance of P. bipes, which was last reported from South Africa during the 1930s. Light and scanning electron microscopy were used for species identification. Knowledge about the presence of these species is crucial because both are potential bloom-forming and associated with several problems having ecological impacts. The presence of both these species has potential in inhibiting the growth of the problematic cyanobacterium Microcystis aeruginosa, as demonstrated by previous studies. It may present a natural and effective solution for the remediation of water bodies subjected to harmful cyanobacterial blooms. These insights are crucial for proactive management of freshwater ecosystems in the country. This paper discusses the morphology, taxonomy, geographical distribution, and some ecological aspects of P. gatunense and P. bipes.

Prescottiella sudanensis is a rare, asymmetrical desmid currently known from only a few countries in equatorial Africa. During the present study, P. sudanensis cells were found in water samples from Vogel Pan located in the far north-eastern side of Namibia, thereby expanding the known geographical distribution of the species. The location of the sampling site, which is situated in a direct line halfway between the Makgadikgadi pans and Okavango Delta towards the east (Botswana) and the Etosha pans towards the west (Namibia), suggests that migrating birds are likely vectors spreading desmids from one waterbody to another. In this paper a morphological description (including dimensions) and micrographs of P. sudanensis are presented, and the known geographical distribution of the species is discussed in relation to migration routes of birds. As the genus and species names are invalid according to ICN Art. 40.1, the names are also validated in this paper.

Although Micrasterias apiculata is widely distributed and frequently found in samples throughout the world, its variety M. apiculata var. tjitjeroekensis, has a very limited geographical distribution. It was previously found in only three locations in the world. The variety was originally described in 1908 from Java, Indonesia (southeast Asia) and 20 years later detected in the Democratic Republic of Congo, Africa. The third finding of M. apiculata var. tjitjeroekensis was during the late 1980's in KwaZulu-Natal, South Africa, but it was described incorrectly under the name M. apiculata var. lacerata f. ornata. M. apiculata var. lacerata f. ornata closely resembles M. apiculata var. tjitjeroekensis and due to similarities, it is proposed to reduce the name M. apiculata var. lacerata f. ornata as a synonym of M. apiculata var. tjitjeroekensis. In this case, the current finding of M. apiculata var. tjitjeroekensis, in samples from northern Mozambique near the Tanzanian border, repre-sents the fourth record of its presence in the world, the third for Africa, and the first for Mozambique. Up to now only French and German descriptions, together with line drawings, of M. apiculata var. tjitjeroekensis were available. This paper presents the first English description of the cell morphology, as well as the first photomicrographs, illustrating structures previous portrayed in line drawings. Based on new findings, it is proposed that the minimum value of existing cell dimension ranges should be adjusted. A lectotype for M. apiculata var. tjitjeroekensis is designated here.(c) 2022 SAAB. Published by Elsevier B.V. All rights reserved.

Four species of the genus Mallomonas (M. alpina, M. annulata, M. caudata, and M. cratis), a unicellular silicascaled chrysophyte, and one species of Synura (S. curtispina), a colonial silica-scaled chrysophyte, were found in the Mooi River, North West Province, South Africa. Entire Mallomonas cells, having intact scales and bristles, were photographed with the scanning electron microscope, enabling accurate species identification. Cells of Synura curtispina, with distinct scales on the surface, was also found. Short descriptions and dimensions of each species are given, and their known geographical distribution and ecological preferences are discussed. Two species (M. annulata and M. cratis) represent first distribution records for Africa, and four species represent first records for South Africa. Only one species (M. alpina) was previously recorded in South Africa. & COPY; 2023 SAAB. Published by Elsevier B.V. All rights reserved.

Micrasterias foliacea (Desmidiales, Zygnematophyceae) is an interesting desmid species as its filamentous life form is quite different from all other species within the genus. Due to the large size of the filaments and cells, accurate species identification is easy. After its original description from Rhode Island (USA) it was recorded from five continents, but no record could be found of its presence in Europe. In this paper a review of the worldwide distribution of M. foliacea (Desmidiales, Zygnematophyceae) is presented, to-gether with notes on the species' ecology. In addition to its currently known geographical distribution, the paper also records the species' presence at two new locations in southern Africa, namely Botswana (Oka-vango River) and Mozambique (Palma, Cabo Delgado). The paper presents a discussion of taxonomical levels of intraspecific taxa, based on morphological characteristics. It is proposed that the taxonomical status of M. foliacea Bailey ex Ralfs f. nodosa should be raised to the variety, as its nodular cell wall thicken-ings are unique morphological features.

This paper reports on the presence of three Mallomonas species (Phylum Ochrophyta) in the Vaal River, South Africa. Scanning electron microscope observations of entire cells with intact scales and bristles allowed accurate identifications of M. corymbosa, M. kenyana and M. portae-ferreae. Descriptions and dimensions of each of the three species are given, their geographical distribution is discussed and physico-chemistry of the water at the time of their finding is presented. M. corymbosa was recorded for the first time in Africa, expanding its known geographical distribution to an additional continent. The climatic preferences of the tropical and subtropical species, M. kenyana were extended to temperate regions in South Africa. These species were present under eutrophic to hypertrophic conditions, a water temperature of 25.4 degrees C, neutral to slightly alkaline water (pH 7.25) and a conductivity value of 440 mu S/cm. (C) 2022 SAAB. Published by Elsevier B.V. All rights reserved.

A unique opportunity to study the sexual reproduction of Chlamydomonas proboscigera was presented when this species reached high densities in the Vaal River, South Africa during 2019. A peculiar and unique way of sexual reproduction in C. proboscigera was revealed for the first time and differs from earlier knowledge on the sexual reproduction of this species. Evidence of copulating gametes obtained during the study proved that C. proboscigera can also reproduce sexually by oogoniogamy and not only through isogamy, as previously believed. Gametes of different sizes copulated with each other and in addition to previously described copu-lation sites, results of this study indicated that gametes may attach to each other at different sites on the cell surface, including at their posterior ends, the posterior end of one gamete can attach to the side of the other gamete (laterally) or the posterior end of one gamete may attach sub-apically to the other gamete. Data on environmental variables at the time of sexual reproduction showed that oogoniogamy occurred under clear water conditions with low temperatures, sufficient nutrient concentrations, and slightly alkaline pH levels. Low temperatures may have played a role in inducing sexual reproduction to form resistant overwintering stages in the form of zygospores. (c) 2021 SAAB. Published by Elsevier B.V. All rights reserved.

Background: Effluents from agricultural activities, metal and peat mining, urban and industrial areas, informal settlements and wastewater treatment plants all influence tributaries feeding the Mooi River. All these land uses ultimately result in a deterioration of water quality in the Mooi River.Objectives: The main objective was to relate the effects of inflowing tributaries to water quality and phytoplankton assemblages in the Mooi River.Method: Physico-chemical environmental variables were compared with water quality objectives and known limits to assess general water quality in the Mooi River over a one-year period. Water quality and phytoplankton in tributarieswere compared to that at sites upstream and downstream from their inflows to determine the extent to which the tributaries affected the Mooi River. Multivariate analysis assisted in the interpretation of phytoplankton and physico-chemical data at the different sites.Results: Seven phytoplankton phyla were identified in the Mooi River. Diatoms and green algae were most dense and diverse. Cyanobacteria were responsible for various problems, especially in the Wasgoedspruit where they dominated and reached high densities. Lowest phytoplankton density and diversity were found in the upstream and downstream sections of the river, while maximum density and diversity were found during summer in the middle reaches. The inflow of tributaries, especially the Wasgoedspruit, had a pronounced effect on water quality downstream. Phytoplankton density and diversity were less affected than chemical variables, especially nutrient concentrations.Conclusion: Various land use activities surrounding the Mooi River’s tributaries contributed to a deterioration of water quality in the main stream of the Mooi River.

Chlamydomonas proboscigera is a unicellular, ellipsoidal-to-spherical chlorophyte distinguished by a flattened papilla, a large spherical pyrenoid and a disc-shaped stigma located anterior in a cup-shaped chloroplast. The species is common in eutrophic water, but also occurs in terrestrial environments, such as soils. Previously, Chlamydomonas proboscigera was only described from certain parts of Europe, Asia and northern Africa (Algeria). The findings of C. proboscigera in South Africa during 2019, represent the first reported record of this species in the southern hemisphere and sub-Saharan Africa.

Blooms of Euglena sanguinea Ehrenberg were observed at two different locations in South Africa, Mpumalanga province during 2016 and Limpopo province during 2020. Besides being responsible for a blood-red discolouration of the water, the species is also toxic, causing fish mortalities. Samples from South Africa were dominated by E. sanguinea and very low concentrations and diversity of other algal species were present. Microscopic studies revealed that the size ranges and the morphology of the cells corresponded to descriptions of the species in literature. High quality micrographs, illustrating the general cell structure and most features used for accurate identification, are provided. Intensive literature searches allowed mapping of the worldwide geographical distribution of the species, which revealed that it was sparsely distributed throughout Africa, because it was reported from only seven countries. Only one previous record of its presence in experimental ponds in South Africa exists, rendering this study a second record for its presence in the country.