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In South Africa, the role of reptilian ticks in the transmission of haemoparasites is lacking, in part, due to limited information on tick diversity and their associated haemoparasites. The aim of this research was to identify tick species parasitizing reptiles and to molecularly screen these ectoparasites for species of the blood apicomplexan genus Hepatozoon. Samples were collected from Ndumo Game Reserve, KwaZulu-Natal, and the Cape Columbine region, Western Cape. Reptiles collected included 2 snakes, 2 monitor lizards of a single species respectively, as well as 17 tortoises of four species. Ticks collected from these were morphologically identified as Amblyomma latum (n = 2) and Amblyomma marmoreum (n = 98), this identification was molecularly confirmed using 16S rRNA and CO1 genes. Screening for Hepatozoon was done by amplifying the 18S rRNA gene. A species of Hepatozoon, Hepatozoon fitzsimonsi, was identified from A. marmoreum ticks, with an overall prevalence of 10%. This Hepatozoon species, has been described parasitizing tortoises from southern Africa, and has been reported from ticks infesting tortoises from Kenya, East Africa. Even though ticks have been suggested to be the likely vector of this Hepatozoon species, with this supported by the findings of Hepatozoon-like developmental stages in ticks collected off of infected tortoises, a recent systematic revision placed this species in a newly erected genus Bartazoon, a genus vectorised by biting insects. The present study thus provides further support for ticks acting as the potential vectors of H. fitzsimonsi.

INTRODUCTION Parasites of the genus Gyrodactylus von Nordmann, 1832, are predominantly parasites of freshwater and marine bony fishes. To date, 40 species of the genus have been described from Africa, with only 6 of these reported from South Africa. This represents only a small fraction of the known diversity of almost 500 species known worldwide. METHODS In total, 43 of Straighhfin barb, Enteromius paludinosus were collected from Barberspan Bird Sanctuary, North West Province, South Africa. Monogenean parasites were isolated from the fins and fixed on microscope slides in ammonium picrate glycerine. Morphometric evaluation of opisthaptoral hard parts confirmed the identity of these specimens as a new species. RESULTS The description of Gyrodactylus paludinosus sp. nov. is presented. The new species has well-developed, slightly curved superficial inner roots and well-developed rectangular-like ventral bar membrane. Despite the small differences between the hamuli size, it can be distinguished from its congeners, G. kyogae and G. ivindoensis, the only species known from small African barbs, by the shape of ventral bars and marginal hook sickle propers. CONCLUSION The description of Gyrodactylus paludinosus n. sp. increases the total number of Gyrodactylus spp. known from African cyprinid fish to three. Undoubtedly, more attention should be given to studies on small barbs as potential hosts for new species.

The branchial attaching, fish parasitic genus Mothocya Costa, in Hope, 1851 is recorded for the first time from Nigerian brackish waters on Monodactylus sebae (Perciformes: Monodactylidae). Mothocya andonin. sp. is characterised by a trapezoid-shaped cephalon with a subtruncate rostrum; pereonite 1 anterolateral angles only reaching to the posterior margin of the eyes; particularly large and wide coxa 7 extending to pleonite 4; pereopod 7 with a narrow basis; broadly rounded pleotelson; and uropods extending to the pleotelson posterior margin, with subequal rami. Mothocya powellin. sp. is characterised by its small size (7 mm); a posteriorly ovoid body shape; cephalon anterior margin truncate; a short pleon with pleotelson lateral margins converging to a narrowly rounded apex; pleonite lateral margins overlapped by pereonite 7; slender uropods that extend to the posterior margin of the pleotelson with the uropodal exopod almost double the length of the endopod., Graphical abstract Image 1, Highlights • Mothocya andoni n. sp. and Mothocya powelli n. sp. are described. • First records of Mothocya from Nigeria. • Full descriptions and identifying characteristics for the two new species are provided. • Increased knowledge on the understudied eastern South Atlantic.

Thirteen species of sea lice (family Caligidae) are reported from a range of elasmobranch and actinopterygian fishes caught off South Africa or obtained from public aquaria in South Africa. Two new species of Caligus Müller, 1785 are described: C. linearisn. sp. from Pomatomus saltatrix (Linnaeus) and C. tumulusn. sp. from Chrysoblephus cristiceps (Valenciennes). A supplementary description is provided for both sexes of Caligus tetrodontis Barnard, 1948 taken from Amblyrhynchotes honckenii (Bloch) and previous records of this parasite from South African fishes are critically reviewed. It is concluded that Caligus material from Arothron hispidus Linnaeus was previously misidentified as C. tetrodontis and is in urgent need of re-examination. Morphological and molecular observations on Caligus furcisetifer Redkar, Rangnekar & Murti, 1949 indicate that this copepod is phenotypically and genetically identical to Lepeophtheirus natalensis Kensley & Grindley, 1973, and the latter becomes a junior subjective synonym of C. furcisetifer. We include new geographical distribution records for Caligus longipedis Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905 and Lepeophtheirus spinifer Kirtisinghe, 1937, extending into South African waters, as well as both new distribution and host records for Alebion gracilis Wilson, 1905, Caligus dakari van Beneden, 1892 and Lepeophtheirus acutus Heegaard, 1943. The molecular analysis confirmed the monophyly of the genus Caligus. The South African species of Caligus did not cluster together, but the two included South African species of Lepeophtheirus were recovered as sister taxa.

Due to their unusual life cycle that includes parasitic larval and free living adult stages, gnathiid isopods are typically overlooked in biodiversity surveys, even those that focus on parasites. While the Philippines sits within the region of highest marine biodiversity in the world, the coral triangle, no gnathiid species have been identified or described from that region. Here we present the first records of two gnathiid species collected from the Visayas, central Philippines: Gnathia malaysiensis Müller, 1993, previously described from Malaysia, and G. camuripenis Tanaka, 2004, previously described from southern Japan. This paper provides detailed morphological redescriptions, drawings and scanning electron microscope images as well as the first molecular characterisation of both species, Furthermore, a summary of the Central-Indo Pacific Gnathia species is provided.

A fish parasitic isopod recently reported from India as Anilocra leptosoma Bleeker, 1857, was re-examined and morphologically compared to five closely related species: A. capensis Leach, 1818, A. clupei Williams and Bunkley-Williams, 1986, A. leptosoma Bleeker, 1857, A. paulsikkeli Welicky and Smit, 2019 and A. pilchardi Bariche and Trilles, 2006. This species was sequenced and compared to other known Anilocra species based on mitochondrial cytochrome c oxidase subunit I (COI) gene fragments. Both morphological and molecular data corroborate that the Anilocra species parasitising the clupeid fish Tenualosatoli (Valenciennes, 1847) from India should be recognised as a new species, and we describe Anilocra grandmaae n. sp. based on the holotype and paratype females. The key characters of A. grandmaae n. sp. include the body being less than 4.0 times as long as wide; antennula article 3 anterodistal margin expanded, 1.2–1.4 times as wide as long; pleonite 1 concealed by pereonite 7 and lateral margin posteriorly produced; pereopods 1–4 with three nodules on dactylus; endopod of pleopods 3–5 with a proximomedial lobe and folding; and pleotelson ovate, with lateral margins converging smoothly to a caudomedial point., Graphical abstract Image 1, Highlights • Description of a first new Anilocra fish parasitic isopod from India. • First molecular characterisation of a cymothoid isopod from India. • Anilocra grandmaae n. sp. is genetically more closely related to species from the Caribbean than Africa. • First record of a cymothoid isopod parasitising the clupeid fish Tenualosa toil.

Chonopeltis lisikili Van As and Van As, 1996 was original described from the Eastern Caprivi (Namibia) and the Okavango System (Botswana), collected from five Synodontis Cuvier, 1816 (Mochokidae) species. This fish genus is endemic to Africa, with 130 valid species, making it one of the most species-rich and widely distributed mochokid catfish family. During parasitological surveys conducted in the Phongolo River (South Africa), a Chonopeltis Thiele, 1900 species was collected from Synodontis zambezensis Peters, 1852. In total, 21 adult females, four adult males, as well as representatives of the larval developmental stages were found. After morphological comparison, this branchiuran was identified as C. lisikili. This paper provides additional information on body measurements and morphological information of all the life stages of the Phongolo material. Information on Chonopeltis material collected from the Okavango River, Botswana, not yet published is also included as well as the first molecular characterisation of a Chonopeltis species using COI and 18 S rRNA partial sequencing. The endemicity of the host and fish lice necessitates a discussion on the host origin and distribution in more than one river system, particularly referring to host specificity for Chonopeltis species., Graphical abstract Image 1, Highlights • First COI sequence for genus Chonopeltis. • First phylogenetic analysis of Branchiurans using 18 S rRNA. • New host and locality record for Chonopeltis lisikili. • First illustrations of the majority of C. lisikili life stages, in fact for any of the known Chonopeltis species.

The global invasive anguillid gill parasite Pseudodactylogyrus anguillae (Yin and Sproston, 1948) has only recently been documented from eels in South Africa. As there is no known eel trade in South Africa, the source of introduction of this parasite has been debated, and its status as an alien parasite was rendered uncertain. We report on the first infection of Pseudodactylogyrus anguillae from the giant mottled eel Anguilla marmorata from the Phongolo River (South Africa) using classic morphological and molecular methodologies and clarify the introduction status category of this parasite as alien and invasive.

The monogenean genus Heterobothrium (Monogenea: Diclidophoridae) currently consists of 12 accepted species described globally from various pufferfishes (Tetraodontidae). This includes the economically important Heterobothrium okamotoi Ogawa 1991 that causes severe disease in the cultured tiger puffer Takifugu rubripes in Japan. During parasitological surveys targeting near shore marine fishes of South Africa, a new Heterobothrium was discovered on the gills of five evileye pufferfish Amblyrhynchotes honckenii with a prevalence of 100% and mean intensity of 23 (4-72). Specimens were morphologically studied using both light and scanning electron microscopy and molecularly characterized by sequencing the partial ribosomal gene 28S. Heterobothrium victorwepeneri n. sp. differs from its 12 congeners by a combination of morphological characters, such as fourth clamp pair (anteriormost, 180° inverted) as the smallest with some of the sclerites differing in shape from the other pairs, 8 to 9 genital hooks, number of testes 40-50, and absent isthmus. The 28S tree depicted two main branches, one clustering together species of mazocraeidean families while the other clustered together only species of the Diclidophoridae. Heterobothrium victorwepeneri n. sp. is the first species of its genus to be recorded and described from South Africa and from the tetraodontid A. honckenii. This study also provides for the first time 28S sequence for a species of this highly host-specific genus.

Brucethoa bharata gen. et sp. nov. is described from the host fish Glossanodon macrocephalus Bineesh and Endo, 2019 (Argentinidae), at depths of 300–600 metres from the south-west coast of India. T...

Significance The Calvin cycle is the most important carbon fixation pathway in the biosphere. However, its carboxylating enzyme Rubisco also accepts oxygen, thus producing 2-phosphoglycolate. Phosphoglycolate salvage pathways were extensively studied in photoautotrophs but remain uncharacterized in chemolithoautotrophs using the Calvin cycle. Here, we study phosphoglycolate salvage in the chemolithoautotrophic model bacterium Cupriavidus necator H16. We demonstrate that this bacterium mainly reassimilates 2-phosphoglycolate via the glycerate pathway. Upon disruption of this pathway, a secondary route, which we term the malate cycle, supports photorespiration by completely oxidizing 2-phosphoglycolate to CO2. While the malate cycle was not previously known to metabolize 2-phosphoglycolate in nature, a bioinformatic analysis suggests that it may support phosphoglycolate salvage in diverse chemoautotrophic bacteria., Carbon fixation via the Calvin cycle is constrained by the side activity of Rubisco with dioxygen, generating 2-phosphoglycolate. The metabolic recycling of phosphoglycolate was extensively studied in photoautotrophic organisms, including plants, algae, and cyanobacteria, where it is referred to as photorespiration. While receiving little attention so far, aerobic chemolithoautotrophic bacteria that operate the Calvin cycle independent of light must also recycle phosphoglycolate. As the term photorespiration is inappropriate for describing phosphoglycolate recycling in these nonphotosynthetic autotrophs, we suggest the more general term “phosphoglycolate salvage.” Here, we study phosphoglycolate salvage in the model chemolithoautotroph Cupriavidus necator H16 (Ralstonia eutropha H16) by characterizing the proxy process of glycolate metabolism, performing comparative transcriptomics of autotrophic growth under low and high CO2 concentrations, and testing autotrophic growth phenotypes of gene deletion strains at ambient CO2. We find that the canonical plant-like C2 cycle does not operate in this bacterium, and instead, the bacterial-like glycerate pathway is the main route for phosphoglycolate salvage. Upon disruption of the glycerate pathway, we find that an oxidative pathway, which we term the malate cycle, supports phosphoglycolate salvage. In this cycle, glyoxylate is condensed with acetyl coenzyme A (acetyl-CoA) to give malate, which undergoes two oxidative decarboxylation steps to regenerate acetyl-CoA. When both pathways are disrupted, autotrophic growth is abolished at ambient CO2. We present bioinformatic data suggesting that the malate cycle may support phosphoglycolate salvage in diverse chemolithoautotrophic bacteria. This study thus demonstrates a so far unknown phosphoglycolate salvage pathway, highlighting important diversity in microbial carbon fixation metabolism.

Fishes of the order Siluriformes, known as catfishes, have a global distribution with more than 3,600 valid species of which 2,087 occur in the Neotropical region. Despite being highly diverse, abundant, and of economic importance as food and ornamental fishes, knowledge about the diversity and distribution of their helminth parasites is fragmentary and scarce. Eight species of catfishes (Pterodoras granulosus, Trachydoras paraguayensis, Pimelodella avanhandavae, Loricariichthys platymetopon, Pterygoplichthys ambrosettii, Rhinelepis aspera, Hemisorubim platyrhynchos, and Sorubim lima) from the Aguapeí River, Upper Paraná River basin, municipality of Castilho, São Paulo State, Brazil, were surveyed for helminth parasites. Collected fishes were weighed, measured, and examined for helminth parasites following standard methodology. Fifty helminth parasite taxa (23 monogeneans, 13 digeneans, 11 nematodes, and three cestodes) were found from a total of 405 fishes screened. The helminth taxon that showed the highest mean intensity of infection and mean abundance was the nematode Rondonia rondoni from P. granulosus, followed by the nematode Parasynodontisia petterae from R. aspera. The ecological analyses were carried out at the component community level and at the infracommunity level. Trachydoras paraguayensis had the richest helminth component community. Pterygoplichthys ambrosettii had the most diverse helminth component community and R. aspera had the lowest. Both hosts are loricariids and have similar diet. However, the high parasite diversity of P. ambrosettii is due to the number of dactylogyrids species found (10), which are directly transmitted, whereas only three dactylogyrid species were found in R. aspera. At infracommunity level, the nematode species R. rondoni and P. petterae dominated the parasite communities. This study presents 38 new host records, contributing considerably to increase the diffuse knowledge of helminth parasites of Neotropical siluriforms., Graphical abstract Image 1, Highlights • Fifty helminth parasite taxa were recovered from 405 catfishes surveyed. • Monogenea was the most diverse group, representing 46% of the helminth taxa found. • Thirty-eight new host records are presented.

Haemogregarine (Apicomplexa: Adeleorina) blood parasites are commonly reported from anuran hosts. Dactylosomatidae (Jakowska and Nigrelli, 1955) is a group of haemogregarines comprising Dactylosoma Labbé, 1894 and Babesiosoma Jakowska and Nigrelli, 1956. Currently Dactylosoma and Babesiosoma contain five re-cognised species each. In the current study, a total of 643 anurans, comprising 38 species, 20 genera, and 13 families were collected from South Africa (n = 618) and Belgium (n = 25), and their blood screened for the presence of dactylosomatid parasites. Three anuran species were found infected namely, Ptychadena anchietae (Bocage, 1868) and Sclerophrys gutturalis (Power, 1927) from South Africa, and Pelophylax lessonae (Camerano, 1882) from Belgium. Based on morphological characteristics, morphometrics and molecular results a new dactylosomatid, Dactylosoma kermiti n. sp. is described form Pty. anchietae and Scl. gutturalis. The species of Dactylosoma isolated from Pel. lessonae could not, based on morphological or molecular analysis, be identified to species level. Phylogenetic analysis shows species of Dactylosoma infecting anurans as a monophyletic group separate from the other haemogregarine groups. Additionally, the mosquitoes Uranotaenia (Pseudoficalbia) ma-shonaensis Theobald, 1901 and U. (Pfc.) montana Ingram and De Meillon, 1927 were observed feeding on Scl. gutturalis in situ and possible dividing stages of this new parasite were observed in the mosquitoes. This study is the first to describe a dactylosomatid parasite based on morphological and molecular data from Africa as well as observe potential stages in possible dipteran vectors. This paper forms part of a VLIR-UOS TEAM funded project (ZEIN21013PR396), co-funded by the National ResearchFoundation of South Africa (NRF project CPRR160429163437, grant105979, NJ Smit, PI). The financial assistance of the NRF towards ECNsupported by the DAAD-NRF doctoral scholarship (Grant UID: 108803), and the VLIR-OUS university scholarship (ID 0620854/Contract000000076310), is acknowledged

In this study we explore the sub-lethal effects of two malaria vector control pesticides, deltamethrin and dichlorodiphenyltrichloroethane (DDT), on Xenopus laevis by incorporating different levels of biological organisation. Pesticide accumulation in frog tissue was measured alongside liver metabolomics and individual swimming behaviour to assess whether changes presented at these different levels, and if such changes could be linked between levels. Results showed evidence of concentration dependent accumulation of DDT and its metabolites, but no measurable accumulation of deltamethrin in adult X. laevis after 96 h of exposure. Both DDT and deltamethrin were shown to cause alterations in the liver metabolome of X. laevis. We also showed that some of these changes can be enhanced in exposure to a mixture of these two pesticides. Initial behavioural responses recorded directly after exposure were seen in the form of decreased activity, less alterations between mobility states, and less time spent at the water surface. This response persisted after 96 h of exposure to a mixture of the two pesticides. This study shows that sub-lethal exposure to pesticides can alter the biochemical homeostasis of frogs with the potential to cascade onto behavioural and ecological levels in mixture exposure scenarios.

Organochlorine pesticides (OCPs) in South Africa have for the most part been banned, except dichlorodiphenyltrichloroethane (DDT) which is still used as malaria vector control. The aim of this study was to determine OCP residues in the aquatic fauna of one of South Africa's most populated areas, Soweto. Risk to human health through OCP exposure via fish consumption was investigated. Clarias gariepinus was chosen as bioindicator because it is an apex predator that is in abundance, but is also a valued food source. Dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and chlordanes (CHLs) were detected in the fish tissue with the DDTs being the most prevalent at all sites. Of the three locations, Fleurhof, Orlando, and Lenasia, the latter location's fish had the highest ΣOCP load, ranging between 81 and 1190 ng/g wm. The DDTs were determined to be from historic use, whereas the CHL levels indicated more recent inputs. Although the possibility of illegal use cannot be excluded completely, the presence of OCPs outside of their allowed areas of use indicate that these compounds not only stay in the aquatic systems long term, but may be of concern in areas previously not considered high risk areas. The OCP residues in C. gariepinus from the study area pose an extremely high risk to human health when consumed, and has a cancer risk as high as 1 in 10. This potential problem should be kept in consideration when developing national health and conservation strategies.

Schizophrenia is a heritable complex phenotype associated with a background risk involving multiple common genetic variants of small effect and a multitude of environmental exposures. Early twin and family studies using proxy-genetic liability measures suggest gene-environment interaction in the etiology of schizophrenia spectrum disorders, but the molecular evidence is scarce. Here, by analyzing the main and joint associations of polygenic risk score for schizophrenia (PRS-SCZ) and environmental exposures in 1,699 patients with a diagnosis of schizophrenia spectrum disorders and 1,542 unrelated controls with no lifetime history of a diagnosis of those disorders, we provide further evidence for gene-environment interaction in schizophrenia. Evidence was found for additive interaction of molecular genetic risk state for schizophrenia (binary mode of PRS-SCZ above 75% of the control distribution) with the presence of lifetime regular cannabis use and exposure to early-life adversities (sexual abuse, emotional abuse, emotional neglect, and bullying), but not with the presence of hearing impairment, season of birth (winter birth), and exposure to physical abuse or physical neglect in childhood. The sensitivity analyses replacing the a priori PRS-SCZ at 75% with alternative cut-points (50% and 25%) confirmed the additive interaction. Our results suggest that the etiopathogenesis of schizophrenia involves genetic underpinnings that act by making individuals more sensitive to the effects of some environmental exposures. ispartof: WORLD PSYCHIATRY vol:18 issue:2 pages:173-182 ispartof: location:Italy status: published

The branchial-attaching cymothoid genus, Elthusa Schioedte & Meinert, 1884 is a genus with a worldwide distribution of 36 species, including the three species described here. Elthusaraynaudii (Milne Edwards, 1840) is the only species that has been described from southern Africa. All South African material held at the National Museum of Natural History, Paris, France (MNHN) and the Iziko South African Museum, Cape Town (SAMC) identified as, or appearing to belong to, Elthusa was examined. Four species were identified, Elthusaraynaudii and three species that proved to be undescribed. Elthusaxenasp. n. can be distinguished by an evenly rounded pereonite 1 anterior margin, a roughly rectangular pleotelson, and narrowly rounded uropod apices that extend to more than half the length of the pleotelson. Elthusaacutinasasp. n. is identified by the produced and narrowly rounded cephalon anterior margin, acute uropods that are shorter than half the length of the pleotelson, and pereonite 1 anterior margin with medial projection. Elthusarotundasp. n. is characterised by the round body shape, broadly rounded uropod apices, and protrusions on the proximal and lateral margins of the merus and carpus of pereopod 7. A key to the South African Elthusa species is provided, together with a table summarising the hosts and localities of the 33 previously known species of Elthusa.

South African clinids are a major component of the temperate intertidal regions that are also known to participate in life cycles and transmission of several groups of parasites. However, the knowledge of trematode diversity of these fishes is incomplete. In this study, two species of Clinus Cuvier, the super klipfish Clinus superciliosus (Linnaeus) and the bluntnose klipfish Clinus cottoides Valenciennes, were collected from six localities along the South African coast and examined for the presence of trematodes. Metacercariae of Cardiocephaloides Sudarikov, 1959 were found in the eye vitreous humour and brain of C. superciliosus and in the eye vitreous humour of C. cottoides. Detailed analyses integrating morphological and molecular sequence data (28S rDNA, ITS2 rDNA-region, and COI mtDNA) revealed that these belong to two species, Cardiocephaloides physalis (Lutz, 1926) and an unknown species of Cardiocephaloides. This study provides the first report of clinid fishes serving as intermediate hosts for trematodes, reveals that the diversity of Cardiocephaloides in South Africa is higher than previously recorded, and highlights the need for further research to elucidate the life cycles of these trematode species. The broad geographical distribution of Cardiocephaloides spp. was confirmed in the present study based on molecular sequence data. The host-parasite interactions between clinid fishes and metacercariae of Cardiocephaloides are yet to be explored.

The digenetic trematode family Gorgocephalidae comprises just a few species, and the literature devoted to the lineage consists of only a handful of reports. With one exception, all reports have been based on material collected in the Indo-West Pacific, an expansive marine ecoregion stretching from the east coast of Africa to Easter Island, Hawaii and French Polynesia. We collected adult and intramolluscan gorgocephalids from kyphosid fishes and littorinid gastropods from several Australian localities, and from South Africa and French Polynesia. Specimens of Gorgocephalus kyphosi and G. yaaji were collected from, or near, their type-localities, providing new morphological and molecular (COI, ITS2 and 28S) data needed for a revised understanding of species boundaries in the family. Two new species are recognized: Gorgocephalus euryaleae sp. nov. and Gorgocephalus graboides sp. nov. New definitive host records are provided for described species and three new intermediate hosts are identified. These new records are all associated with Kyphosus fishes and littorinid gastropods, reaffirming the restriction of gorgocephalids to these hosts. Most significantly, we provide evidence that G. yaaji is distributed from South Africa to French Polynesia, spanning the breadth of the Indo-West Pacific. Our findings have significant relevance regarding digenean species delineation over geographic range.

Clinus superciliosus was collected for element analysis from six localities along the South African west and south coasts. Concentrations in muscle and liver were determined, considering size and sex. No significant positive correlation between size and concentrations were detected, except for Mn and Sn in liver from Simons Town marina, while no significant differences in sex were detected. The majority of element concentrations were significantly higher in fish from Tsitsikamma in the Garden Route and the small town Chintsa, while some concentrations were significantly higher in muscle at Simons Town marina. Land-use activities had a limited role in element bioaccumulation in klipfish. Element concentrations were influenced by large scale oceanographic processes (currents; upwelling) and localised seasonal geogenic derived run-off. Limited data on element accumulation patterns of intertidal fish species in South Africa, highlights the need for long-term monitoring and further studies on different resident and transient intertidal fish species.

To date, micropollutants from anthropogenic sources cannot be completely removed from effluents of wastewater treatment plants and therefore enter freshwater systems, where they may impose adverse effects on aquatic organisms, for example, on fish. Advanced treatment such as ozonation aims to reduce micropollutants in wastewater effluents and, thus, to mitigate adverse effects on the environment. To investigate the impact and efficiency of ozonation, four different water types were tested: ozonated wastewater (before and after biological treatment), conventionally-treated wastewater, and water from a river (River Ruhr, Germany) upstream of the wastewater treatment plant effluent. Zebrafish (Danio rerio) embryos were used to study lethal and sublethal effects in a modified fish early life-stage test. Mortality occurred during exposure in the water samples from the wastewater treatment plant and the river in the first 24 h post-fertilization, ranging from 12% (conventional wastewater) to 40% (river water). Regarding sublethal endpoints, effects compared to the negative control resulted in significantly higher heart rates (ozonated wastewater), and significantly reduced swimming activity (highly significant in ozonated wastewater and ozone reactor water, significant in only the last time interval in river water). Moreover, the respiration rates were highly increased in both ozonated wastewater samples in comparison to the negative control. Significant differences between the ozonated wastewater samples occurred in the embryonic behavior and heart rates, emphasizing the importance of subsequent biological treatment of the ozonated wastewater. Only the conventionally-treated wastewater sample did not elicit negative responses in zebrafish, indicating that the discharge of conventional wastewater poses no greater risk to embryonic and larval zebrafish than water from the river Ruhr itself. The sublethal endpoints embryonic- and larval behavior, heart rates, and respiration were found to be the most sensitive endpoints in this fish early life-stage test and can add valuable information on the toxicity of environmental samples.

The examination of eight spotted skates, Raja straeleni Poll, resulted in the discovery of four new species of Acanthobothrium van Beneden, 1849, namely A. microhabentes sp. n., A. microtenuis sp. n., A. crassus sp. n., and A. dolichocollum sp. n., located off the Western Cape of South Africa. With a total of over 200 valid species of Acanthobothrium recognised worldwide, the use of an integrative approach becomes imperative in the interest of simplifying interspecific comparisons between congeners. In accordance with this, the four new species were incorporated into the category classification system established by Ghoshroy and Caira in 2001, where they were identified as category 2 species, which, at present, includes 47 recognised species of Acanthobothrium. Nevertheless, each of the four new species exhibits postovarian testes, a most intriguing and highly unusual feature among Acanthobothrium, instantly differentiating them from most congeners. This feature has been reported in 12 congeners, which have previously been considered to be restricted to waters of the Indo-Pacific Ocean. Not only do the four new congeners represent the first species of Acanthobothrium reported from southern Africa, but they also represent the first reported species with postovarian testes from the southern Atlantic Ocean. Regarding the legitimacy of the four new species, only two other category 2 species are reported to exhibit this feature, namely A. popi Fyler, Caira et Jensen, 2009, and A. bobconniorum Fyler et Caira, 2010, to which the four congeners were compared to. Acanthobothrium microhabentes sp. n. is the smallest of the congeners and differs from A. popi and A. bobconniorum by having fewer testes and postovarian testes, a shorter body, fewer proglottids, a shorter scolex, and longer cephalic peduncle. Acanthobothrium microtenuis sp. n. differs from A. popi and A. bobconniorum by having fewer testes and postovarian testes, a shorter scolex, longer cephalic peduncle, and the possession of columnar spinitriches on the anterior region of the terminal proglottid. Acanthobothrium crassus sp.n. differs from A. popi and A. bobconniorum by having fewer postovarian testes, a narrower cirrus-sac, larger vitelline follicles, and a longer cephalic peduncle. Acanthobothrium dolichocollum sp. n. is the longest of the four new species and differs from A. popi and A. bobconniorum by having fewer postovarian testes, more postporal testes, a larger body, more proglottids, larger testes and vitelline follicles, and an exceptionally long cephalic peduncle. Apart from differences in overall size, the four new species differ in a combination of measurements for the scolex, vitelline follicles, muscular pad and cephalic peduncle, and the number of proglottids and testes. The four species were recovered from a previously unexplored host and locality, expanding the host associations and geographical distribution of the genus.

Parasitological examination of freshwater fishes of the Phongolo River in north-eastern KwaZulu-Natal, South Africa resulted in the discovery and morphological and molecular characterisation of a new species of Wenyonia Woodland, 1923 (Cestoda: Caryophyllidea). The new species from the plain squeaker, Synodontis zambezensis Peters (Siluriformes: Mochokidae), is morphologically most similar to Wenyonia acuminata Woodland, 1923, a species reported from three species of Synodontis in north-eastern, western and central Africa (Sudan, Nigeria, Democratic Republic of the Congo). Both these species are markedly different from congeners by having a nematoform body and a digitiform scolex. Wenyonia gracilis sp. n. differs from W. acuminata in its general body size, length and width of main body regions (testicular and uterine regions), a posterior extension of the testes into the uterine region, numerous postovarian vitelline follicles filling the entire medulla, eggs c. 1/3 larger in size, and a scolex with an apical introvert but devoid of longitudinal furrows and a well-defined base. Wenyonia gracilis is the seventh species in the genus and the first autochthonous caryophyllidean ever reported and described from southern Africa (south of the Zambezi River).

This study investigated the occurrence and phylogenetic relationship of protozoan parasites and Ehrlichia infecting domestic animals from three municipalities in uMkhanyakude district of KwaZulu-Natal province, South Africa. A total of 208 blood samples collected from clinically healthy cattle, sheep, goats and dogs from uMkhanyakude district were examined by polymerase chain reaction (PCR) assays, using either genus or species-specific primers to determine the occurrence and phylogenetic relationship of various protozoan parasites and Ehrlichia of veterinary importance. A total of 5/109 (4.6%) cattle were PCR-positive for the presence of Toxoplasma gondii , 33/109 (30.3%) for Babesia bovis, 24/109 (22.02%) for Babesia bigemina and 20/109 (18.3%) for Trypanosoma sp., while 3/10 (30%) of sheep were PCR-positive for Theileria ovis and none of the goats were positive for any of the detected pathogens. The co-infection of 4/109 (3.7%) B. bovis and B. bigemina was detected in cattle. Only Ehrlichia canis was detected in dogs with infection rate of 20/48 (41.7%). Sequences of PCR-positive isolates ( B. bovis, B. bigemina, E. canis, T. ovis and T. gondii ) showed that they were closely related to their relevant species from various countries. These findings have expanded our knowledge about the prevalence and phylogenetic similarity between protozoan parasites and Ehrlichia isolates of South African origin. To date, this is the first study in South Africa to detect T. gondii infections from cattle blood using PCR.

Mass Nile crocodile (Crocodylus niloticus) deaths in Africa’s premier conservation area, the Kruger National Park (KNP), prompted numerous studies to determine possible causes of the sudden die-offs. The majority highlighted the involvement of the anthropocene to crocodile mass mortalities. One of the potential causative agents was identified as legacy compounds such as organochlorine pesticides (OCPs) present in the various aquatic ecosystems of the KNP. Thus, this study aimed to quantify OCP levels in wild crocodiles from the aquatic systems associated with the KNP. As part of a larger study, muscle tissue samples were collected from tails of 12 wild crocodiles. Results indicated that eight of the 19 OCPs analysed for were quantifiable. These included DDTs (2130–167968 ng/g lw), chlordanes (BD – 7583 ng/g lw) and cyclodeines (BD – 872 ng/g lw). Measured concentrations indicated spatial- and sex-related differences in accumulation patterns. DDT and its metabolites, paricularly p,p’-DDE accumulated to the highest concentrations of the OCP groups. Levels of the different groups of OCPs were the highest recorded in recent history from any crocodilian tissue. The different measured OCP residues were between 2.5 and 120 times higher than levels reported in literature, depending on the compound. These results are of ecotoxicological significance and have several management implications. In view of individuals being sampled from a conservation area it emphasizes the fact that pollutants know no boundaries and that premier conservation areas such as the world renowned KNP may be some of the most contaminated areas of the world.

Carbon fixation via the Calvin cycle is constrained by the side activity of Rubisco with dioxygen, generating 2-phosphoglycolate. The metabolic recycling of 2-phosphoglycolate, an essential process termed photorespiration, was extensively studied in photoautotrophic organisms, including plants, algae, and cyanobacteria, but remains uncharacterized in chemolithoautotrophic bacteria. Here, we study photorespiration in the model chemolithoautotroph Cupriavidus necator (Ralstonia eutropha) by characterizing the proxy-process of glycolate metabolism, performing comparative transcriptomics of autotrophic growth under low and high CO2 concentrations, and testing autotrophic growth phenotypes of gene deletion strains at ambient CO2. We find that the canonical plant-like C2 cycle does not operate in this bacterium and instead the bacterial-like glycerate pathway is the main photorespiratory pathway. Upon disruption of the glycerate pathway, we find that an oxidative pathway, which we term the malate cycle, supports photorespiration. In this cycle, glyoxylate is condensed with acetyl-CoA to give malate, which undergoes two oxidative decarboxylation steps to regenerate acetyl-CoA. When both pathways are disrupted, autotrophic growth is abolished at ambient CO2. We present bioinformatic data suggesting that the malate cycle may support photorespiration in diverse chemolithoautotrophic bacteria. This study thus demonstrates a so-far unknown photorespiration pathway, highlighting important diversity in microbial carbon fixation metabolism.

Background The African leopard Panthera pardus pardus (L.) is currently listed as a vulnerable species on the IUCN (International Union for the Conservation of Nature) red list of threatened species due to ongoing population declines. This implies that leopard-specific parasites are also vulnerable to extinction. Intracellular apicomplexan haemoparasites from the genus Hepatozoon Miller, 1908 have been widely reported from wild carnivores in Africa, including non-specific reports from leopards. This paper describes two new haemogregarines in captive and wild leopards from South Africa and provides a tabular summary of these species in relation to species of Hepatozoon reported from mammalian carnivores. Methods Blood was collected from nine captive and eight wild leopards at various localities throughout South Africa. Thin blood smears were Giemsa-stained and screened for intraleukocytic haemoparasites. Gamont stages were micrographed and morphometrically compared with existing literature pertaining to infections in felid hosts. Haemogregarine specific primer set 4558F and 2733R was used to target the 18S rRNA gene for molecular analysis. Resulting sequences were compared to each other and with other available representative mammalian carnivore Hepatozoon sequences from GenBank. Results Two species of Hepatozoon were found in captive and wild leopards. Of the 17 leopards screened, eight were infected with one or both morphologically and genetically distinct haemogregarines. When compared with other species of Hepatozoon reported from felids, the two species from this study were morphometrically and molecularly distinct. Species of Hepatozoon from this study were observed to exclusively parasitize a particular type of leukocyte, with Hepatozoon luiperdjie n. sp. infecting neutrophils and Hepatozoon ingwe n. sp. infecting lymphocytes. Phylogenetic analysis showed that these haemogregarines are genetically distinct, with Hepatozoon luiperdjie n. sp. and Hepatozoon ingwe n. sp. falling in well supported separate clades. Conclusions To our knowledge, this is the first morphometric and molecular description of Hepatozoon in captive and wild African leopards in South Africa. This study highlights the value of using both morphometric and molecular characteristics when describing species of Hepatozoon from felid hosts.

Twenty-one species of acanthocephalans, representative of thirteen genera from ten families of seven orders and three classes, are included in this updated checklist of acanthocephalans in South Africa.Although South Africa appears to have a less diverse acanthocephalan fauna compared to some other countries such as Iran in Asia, or Brazil in South America, this is probably an artefact of fewer parasitological surveys.

Coral reefs harbor the greatest biodiversity per unit area of any ecosystem on earth. While parasites constitute the majority of this biodiversity, they remain poorly studied due to the cryptic nature of many parasites and the lack of appropriate training among coral reef ecologists. Damselfishes (Pomacentridae) are among the most abundant and diverse fishes on coral reefs. In a recent study of blood parasites of Caribbean reef fishes, the first ever apicomplexan blood parasites discovered in damselfishes were reported for members of the genus Stegastes. While these blood parasites were characterized as “Haemohormidium-like”, they appear to be distinct from any other known apicomplexan. In this study, we examined host associations, geographic distributions, and provide further insights on the phylogenetic affiliation of this parasite. A combination of morphological characteristics and 18S rDNA sequences suggest that this parasite may be the same species at multiple sites and occurs from the southern to the northern extreme of the eastern Caribbean, although it appears rare in the north. At present it appears to be limited to members of the genus Stegastes and infects all life history stages. It is most common in benthophagous species that occur in high population densities and appears basal to a major monophyletic clade containing species of coccidia, distinct from the Piroplasmida, the order to which Haemohormidium spp. have been assigned. These findings suggest a possible fecal-oral mode of transmission., Graphical abstract Image 1, Highlights • A new species of Haemorhormidium-like apicomplexan blood parasite has recently been discovered in Caribbean damselfishes. • Morphological and molecular data indicate that it is widespread in the eastern Caribbean. • This parasite is limited to damselfish species of the genus Stegastes and infects juveniles and adults. • It is most common in benthophagous species that occur in high population densities. • This parasite resembles coccidia but 18S rDNA show it to be distinct from known genera, as well as genera of piroplasms.

Haemogregarines (Apicomplexa: Adeleiorina) are a diverse group of haemoparasites reported from almost all vertebrate classes. The most commonly recorded haemogregarines to parasitize anurans are species of Hepatozoon Miller, 1908. To date 16 Hepatozoon species have been described from anurans in Africa, with only a single species, Hepatozoon hyperolli (Hoare, 1932), infecting a member of the Hyperoliidae. Furthermore, only two Hepatozoon species are known from South African anurans, namely Hepatozoon theileri (Laveran, 1905) and Hepatozoon ixoxo Netherlands, Cook and Smit, 2014, from Amietia delalandii (syn. Amietia quecketti) and three Sclerophrys species, respectively. Blood samples were collected from a total of 225 individuals representing nine hyperoliid species from several localities throughout northern KwaZulu-Natal, South Africa. Twenty frogs from three species were found positive for haemogregarines, namely Afrixalus fornasinii (6/14), Hyperolius argus (2/39), and Hyperolius marmoratus (12/74). Based on morphological characteristics, morphometrics and molecular findings three new haemogregarine species, Hepatozoon involucrum Netherlands, Cook and Smit n. sp., Hepatozoon tenuis Netherlands, Cook and Smit n. sp. and Hepatozoon thori Netherlands, Cook and Smit n. sp., are described from hyperoliid hosts. Furthermore, molecular analyses show anuran Hepatozoon species to be a separate monophyletic group, with species isolated from African hosts forming a monophyletic clade within this cluster.

Recently, Mozambique tilapia (Oreochromis mossambicus Peters, 1852) were listed on the IUCN Red List as near-threatened as their populations are at risk due to hybridization. Another factor that potentially contributes to their population decline is that they are regularly infected by the invasive parasitic copepod anchorworm, Lernaea cyprinacea Linnaeus, 1758. Considering anchorworm-infected Mozambique tilapia are common, understanding their condition with respect to infection is difficult as uninfected fish from the same localities have been unavailable for comparison. A severe drought in southern Africa has created hypersaline environments in the Phongolo River floodplain of north-eastern South Africa, such that freshwater parasites cannot survive and uninfected fish are now found. To determine how infection influences host health, infected and uninfected Mozambique tilapia were collected before and during drought conditions, from Nyamiti pan of the Phongolo River floodplain. Anchorworm-infected fish prevalence was recorded, and anchorworms were collected from hosts and identified to the species level using molecular data of the 18S rRNA gene. For each fish, intensity of anchorworm infection, total length, and weights of the gutted body, liver, spleen, and gonads were recorded. Gutted condition factor, hepato-, spleeno-, and gonado-somatic index values per fish, and prevalence of infection per collection were determined. A rapid health assessment was also conducted to determine a health score for each fish. Molecular analyses confirmed the anchorworm studied was L. cyprinacea. Prior to and during drought, prevalence of infection was 100%, and 0%, respectively. Before drought, fish had significantly reduced hepato-, spleeno-, and gonado-somatic index values, and higher health assessment scores, yet significantly higher gutted condition. Anchorworm intensity was indirectly correlated with fish liver and gonad condition. This study demonstrates that host condition and health varies greatly with respect to drought and infection, and provides the necessary data for follow-up studies in post-drought conditions., Graphical abstract Image 1, Highlights • Invasive Lernaea cyprinacea, confirmed by 18S rRNA data, infect Mozambique tilapia. • Severe drought has induced a natural freshwater ectoparasite removal treatment. • Prevalence of anchorworm-infected tilapia was 100% before and 0% during drought. • Anchorworm infection is related to reduced fish health and some host energetics. • Accordingly infection may alter host fitness and population dynamics.

Summary The monogenean, Afrogyrodactylus ardae sp. n., is described from the African tetra, Rhadbalestes septentrionalis (Characiformes: Alestidae), collected from the Niokolo Koba and Gambie Rivers in the Niokolo-Koba National Park, Senegal during 2008. The newly described species can be differentiated from three known species of the genus based on the dimensions of its opisthaptoral hard parts, having the smallest ones, and based on the shape of the marginal hooks sickle. The present finding represents a new host record for the genus Afrogyrodactylus.

Gnathiid isopods are one of the most common fish ectoparasites, and are found in both temperate and tropical oceans. On coral reefs, gnathiids are most active at dusk and dawn, and contribute significantly to trophic dynamics, as they are a prey resource for cleaner fish and parasitize numerous fishes. Gnathiids also inhabit temperate intertidal waters, but their activity patterns and contribution to intertidal trophic dynamics remain unstudied. To provide the first ecological data on temperate intertidal gnathiid activity patterns, 172 gnathiid-freeClinus superciliosuswere set in an intertidal system in Tsitsikamma National Park, South Africa, during early morning, morning, afternoon, early evening, and evening, high and low tide, and within the inter- and infra-tidal zone to examine gnathiid infestation levels. After exposure, gnathiids from each fish were identified to the species level, counted, and their developmental stage was recorded. All gnathiids were identified asGnathiia africana. On average, 1 ± 5SD gnathiids were collected from each fish, and the majority of gnathiids collected were stage 1. Significantly more gnathiids were collected during morning and afternoon compared with all other time periods. The number of gnathiids collected was not influenced by the fish's exposure to high or low tide, or placement within the tide zone. AlthoughG. africanais free from cleaner fish predation because cleaner fish do not reside in temperate intertidal habitat,G. africanaabundance is surprisingly small. Future studies should examine what regulatesG. africanapopulation size and the role they play in temperate intertidal food webs.

Norileca indica (Milne Edwards, 1840) is fully redescribed based on ovigerous females collected from Maputo Bay, Mozambique, from the branchial cavity of the fish host Selar crumenophthalmus Bloch, 1793. An identification key to the species of Norileca Bruce, 1990 is given. Furthermore, a fragment of the mitochondrial cytochrome oxidase I (COI) gene from N. indica was sequenced for the first time. This is the first molecular characterisation of a species of Norileca.

Chonopeltis Thiele, 1900 presently comprises 14 species, it is endemic to Africa and its species show a high degree of host-specificity towards fish families and in some cases, individual fish species. Chonopeltis meridionalis Fryer, 1964 was originally described from Labeo rosae Steindachner collected in the River Nuanetsi in Rhodesia, now Zimbabwe, Limpopo River System. At the time of description C. meridionalis was the most southerly species of the genus. Chonopeltis victori Avenant-Oldewage, 1991 was described from the River Olifants, Mpumalanga, South Africa, which also forms part of the Limpopo River System. The host fish was Labeo rosae and Labeobarbus marequensis (A. Smith), whilst C. koki Van As, 1992 was described from Labeo cylindricus Peters, collected in the River Zambezi, Eastern Caprivi, Namibia. During surveys conducted in 2012, additional material of a species of Chonopeltis was collected from Labeo rosae in the River Olifants. Upon closer examination, the new material was identified as C. meridionalis. Further investigation revealed that C. victori and C. koki share a number of characteristics with C. meridionalis. This paper provides the first scanning electron microscopy of C. meridionalis, includes additional information on fully-mature as well as sub-adult males and females. Finally, it was concluded that C. victori and C. koki are junior synonyms of C. meridionalis.

The new cymothoid species, Elthusa winstoni sp. n., a branchial parasite of fishes from the family Acanthuridae Bonaparte, 1835 in Hawaii, is described and figured. The female adults can be distinguished by the strongly vaulted body and compacted body shape; rostrum with a small median point; short antennae which are close together (only 6 articles in both antennula and antenna); short and wide uropods extending to half the length of the pleotelson; short dactyli on pereopod 7; and large recurved robust setae on the maxilla. This is the first record of an Elthusa Schioedte & Meinert, 1884 species from the Hawaiian Islands and only the fifth cymothoid described from this region.

Fish parasites from the isopod family Cymothoidae have, in recent years, received increased global attention due to both their ecological and economic importance. This is particularly true for the buccal inhabiting genus Ceratothoa Dana, 1852, whose members have been implicated in negatively impacting the health of both farmed and wild-caught fishes. As research on this group increases, so does our understanding of their host specificity and distribution. The aims of this paper were thus to review the current distribution and host records of Ceratothoa and describe a new species, Ceratothoa springbok n. sp. from South Africa. Including the new species described here, there are currently 25 accepted Ceratothoa spp. known from eight of the 12 marine biogeographical realms of the world. The majority of Cymothoidae species are known to occur in the tropical realms, whereas our analyses show that the greatest diversity of Ceratothoa spp. can be found in temperate realms. These results indicate the possibility that Ceratothoa is more diverse in temperate regions. This review also highlights the low diversity of Ceratothoa from the oceans around both North and South America. Current records indicate that species of Ceratothoa parasitise 108 fish species in 76 genera and 41 families. Eleven Ceratothoa spp. demonstrate host specificity up to host genus or family level. Amongst the hosts, members of the Sparidae are parasitised by 13 species of Ceratothoa, making it the host family with the highest diversity of parasites from this genus. The new species, C. springbok n. sp., also parasitises a sparid and was found in the buccal cavity of the carpenter seabream, Argyrozona argyrozona. This new species, the largest of all recorded Ceratothoa (up to 65 mm) and amongst the largest of all Cymothoidae, is characterised by its truncate and ventrally folded frontal margin, pereonite 1 with medial indentations, the wide anterolateral margins of pereonite 1 with an inwardly produced point, and a well-developed carina on the basis of pereopod 7. A key to the southern African Ceratothoa is provided.

Supplementary informationis available for this paper athttps://doi.org/10.1038/s41467-020-18906-7, Six CO2 fixation pathways are known to operate in photoautotrophic and chemoautotrophic microorganisms. Here, we describe chemolithoautotrophic growth of the sulphate-reducing bacterium Desulfovibrio desulfuricans (strain G11) with hydrogen and sulphate as energy substrates. Genomic, transcriptomic, proteomic and metabolomic analyses reveal that D. desulfuricans assimilates CO2 via the reductive glycine pathway, a seventh CO2 fixation pathway. In this pathway, CO2 is first reduced to formate, which is reduced and condensed with a second CO2 to generate glycine. Glycine is further reduced in D. desulfuricans by glycine reductase to acetyl-P, and then to acetyl-CoA, which is condensed with another CO2 to form pyruvate. Ammonia is involved in the operation of the pathway, which is reflected in the dependence of the autotrophic growth rate on the ammonia concentration. Our study demonstrates microbial autotrophic growth fully supported by this highly ATP-efficient CO2 fixation pathway., We acknowledge Änne-Michaelis and William Newell for assistance with the LC-MS forthe metabolomics experiments and Daniel Amador-Noguez for access to the LC-MS usedfor13C intracellular metabolomic analysis. We thank Ines Cardoso Pereira and John vander Oost for critically reading the manuscript. This research was funded by the Neth-erlands Organisation for Scientific Research (NWO) through SIAM Gravitation Grant024.002.002 and the Innovation Program Microbiology (WUR), NJC acknowledgesfunding from NWO through a Rubicon Grant (019.163LW.035) and a Veni Grant(VI.Veni.192.156)., info:eu-repo/semantics/publishedVersion

Anuran filarial nematodes are restricted to two comparatively small subfamilies (Icosiellinae and Waltonellinae) of the filariae that currently comprise six genera and 41 recognised species. However, the life histories of only five anuran filarial nematodes, proposed as an ancestral group based on molecular phylogenetic studies, have been elucidated. Furthermore, data on the natural vectors (in situ) and parasite transmission is limited. In the current study we elucidate the life history of Neofoleyellides boerewors n. gen. n. sp. parasitising the guttural toad, Sclerophrys gutturalis and the mosquito vectors Uranotaenia (Pseudoficalbia) mashonaensis and Uranotaenia (Pseudoficalbia) montana. Additionally, we report on the unique host-seeking behaviour of the mosquito vectors which locate their toad hosts using their calls. The complex host-vector relationship and specialised host-seeking behaviour by these mosquitoes indicate biases towards host species and male toad infections. ispartof: International Journal For Parasitology vol:50 issue:3 pages:177-194 ispartof: location:England status: published

Animal behavioural traits determine trophic interaction strength, which in turn structures ecological communities. Behavioural responses to prey cues can inform upon how prey are perceived and detected and therefore determine whether certain stimuli can increase or dampen predatory efficiency and therefore community structuring. We examined the functional foraging traits of an amphibian predator Xenopus laevis on mosquito larvae (Culex sp.), with regard to responses towards different prey cues. We assessed a suite of foraging behaviours exhibited when supplied with three abundances of live prey (2, 4 and 20); non-injury prey cues; prey injury kairomones from mechanically damaged prey in order to determine the importance of cues in stimulating foraging. High abundance of live prey caused frogs to visit the top of the arena significantly more than in the other treatments. This suggests that hydromechanical and visual cues alert X. laevis to prey items in different spatial zones, which results in foraging where the prey have aggregated, while the non-injury prey cue resulted in a decrease in foraging behaviours. The injury kairomone cue elicited a significantly farther distance travelled, and similar responses in terms of velocity of movement and duration of time spent moving when supplied with 20 live prey items. Previous work on X. laevis predation has focused on prey detection via lateral line sensitivity, however, the strength of response elicited by the prey injury kairomone treatment indicates that there are also complex olfactory pathways involved in detecting prey items. This is possibly related to abiotic context (i.e. turbid ponds) and high predator density in the wild.

Seventy-seven alien freshwater species are currently naturalised in South Africa. This list includes 7 protozoan, 1 cnidarian, 2 cestode, 13 monogenean, 1 nematode, 1 oligochaete, 6 crustacean, 16 insect, 7 mollusc and 21 fish species. Their origins include all continents except Antarctica and the main pathways for their introduction into the wild are intentional releases (42% of taxa), as parasitic contaminants (35%) or stowaways (14%). Escape from captivity has been relatively unimportant (one fish and one crayfish) and direct introductions for fisheries (49% of taxa), biological control (19%) and stowaways or contaminants (22%) are the most common vectors. The chapter provides an overview of the alien freshwater taxa that are naturalised in South Africa and offers insights into which areas of research are data deficient. Generally, the introduction pathways and vectors for intentionally introduced taxa, such as insects imported for biological control or fishes introduced for fisheries, are well understood and documented. Data on other taxa, and particularly on invertebrates, are scant and only certain groups, such as the parasites of fishes, and snails, for which there is directed research interest, are documented. As a result, increased survey effort is urgently required.

Due to the increasing consumption of platinum (Pt), especially in automobile exhaust catalysts, environmental concentrations of Pt are of emerging concern worldwide. Limited information exists on environmental concentrations, particularly in Pt mining regions, while South Africa is the world’s main supplier of Pt. Moreover, other metals are also released as by-products of Pt mining, which might also cause environmental concern. Certain fish parasite taxa have the ability to accumulate metals orders of magnitude higher than their hosts and can be used to reliably detect metals with naturally low abundance. Studies on Pt accumulation in parasite-host systems are limited. Therefore, the aims of the present study were (1) to determine the accumulation of a variety of metals (cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), platinum (Pt), and zinc (Zn)) in helminth fish parasites compared with their hosts from a reference site and an impoundment impacted by Pt mining activities; (2) to assess whether there is a difference between bioaccumulation of metals in infected and uninfected hosts, as well as between hosts with different infection intensities; and (3) to compare the biomarker responses (acetylcholine esterase activity (AChE), metallothionein content (MT), catalase activity (CAT), reduced glutathione content (GSH), malondialdehyde content (MDA), protein carbonyls induction (PC), superoxide dismutase activity (SOD), and cellular energy allocation (CEA)) between infected and uninfected hosts. The cestode Atractolytocestus huronensis accumulated significantly higher concentrations of Cr, Ni, and Pt than their host Cyprinus carpio, while the nematode Contracaecum sp. accumulated significantly higher concentrations of Pt and Zn than their host Clarias gariepinus. Infected fish showed lower metal concentrations compared to uninfected fish, while the parasites had no significant effects on their hosts’ biomarker responses. The parasites demonstrated the bioavailability of metals derived from Pt mining activities and their ability to resist its toxic effects. Thus, these parasites are promising sensitive accumulation indicators for Cr, Ni, Pb, and Pt contaminations from Pt mining activities.

Formate can be directly produced from CO2 and renewable electricity, making it a promising microbial feedstock for sustainable bioproduction. Cupriavidus necator is one of the few biotechnologically-relevant hosts that can grow on formate, but it uses the Calvin cycle, the high ATP cost of which limits biomass and product yields. Here, we redesign C. necator metabolism for formate assimilation via the synthetic, highly ATP-efficient reductive glycine pathway. First, we demonstrate that the upper pathway segment supports glycine biosynthesis from formate. Next, we explore the endogenous route for glycine assimilation and discover a wasteful oxidation-dependent pathway. By integrating glycine biosynthesis and assimilation we are able to replace C. necator's Calvin cycle with the synthetic pathway and achieve formatotrophic growth. We then engineer more efficient glycine metabolism and use short-term evolution to optimize pathway activity. The final growth yield we achieve (2.6 gCDW/mole-formate) nearly matches that of the WT strain using the Calvin Cycle (2.9 gCDW/mole-formate). We expect that further rational and evolutionary optimization will result in a superior formatotrophic C. necator strain, paving the way towards realizing the formate bio-economy.

Biomarkers are applied as early warning indicators of organisms’ exposure to pollutants. The aim of this study was to utilise a multi-biomarker approach in the freshwater shrimp Caridina nilotica (Decapoda: Atyidae) as indicators of persistent pollutant exposure. A suite of biomarkers was selected to cover oxidative stress and damage, and energetics of the organisms. Five sites, representing an agricultural and pesticide application gradient, were sampled during two flow related hydro-periods in rivers of the Phongolo floodplain, north-eastern South Africa. Cytochrome P450 (CYP) activity was significantly higher in shrimp at sites directly adjacent to regions of increased human activity. Increased oxidative responses, i.e. catalase (CAT; p

Reliable data on the diversity of the genus Diplostomum (Digenea: Diplostomidae) parasitising freshwater fishes in South Africa, as well as in Africa, is almost non-existent. Most of the morphology-based identifications of species within this genus reported from Africa require critical revision. The aim of the present study was to determine the diversity of Diplostomum metacercariae in South African fishes applying molecular and traditional morphological techniques. To achieve this aim, a total of 216 fishes belonging to 21 species collected in the Rivers Phongolo, Riet, Usuthu and Mooi in three provinces of South Africa were examined. Metacercariae of Diplostomum were recovered from the eye lenses of 38 fishes belonging to five species of the families Anguillidae, Cichilidae and Mochokidae, with an overall low prevalence of infection (18%). Metacercariae were subjected to morphological study and molecular sequencing of the partial mithochondrial cox1 and ribosomal 28S rDNA genes as well as of ribosomal ITS1-5.8S-ITS2 region. Morphological and phylogenetic analyses revealed the presence of three species which matched those previously reported from Nigeria, Iraq and China, therefore those from Tilapia sparrmanii and Synodontis zambezensis were named Diplostomum sp.; those from Anguilla labiata, Oreochromis mossambicus and S. zambezensis were named Diplostomum sp. 14; and those from Pseudocrenilabrus philander were named Diplostomum sp. 16. Geographic distribution of several species of Diplostomum appeared to be wider than expected. Morphological description and novel sequence data generated during this study will contribute to the elucidation of the life cycles of Diplostomum sp., Diplostomum sp. 14 and Diplostomum sp. 16 and advance further research of diplostomids in Africa., Graphical abstract Image 1, Highlights • Exploring the diversity of trematodes in freshwater fishes from South Africa. • Molecular evidence for three species of Diplostomum in the Southern Hemisphere. • First detailed morphological data for metacercariae of Diplostomum in South Africa. • First report on the distribution of Diplostomum across the Palaearctic and Afrotropics.

Trypanosomes are ubiquitous blood parasites of fishes and at least 16 species were originally described infecting African freshwater fishes. This number was later reduced to six and in the late 1990s it was proposed that most records of freshwater fish trypanosomes across Africa are Trypanosoma mukasai Hoare, 1932. Recently, results from a molecular analysis of fish trypanosomes from the Okavango Delta, Botswana, reported the presence of at least two genotypic groups and concluded that the identification of T. mukasai remains problematic. The aims of the present study were thus to elucidate the life cycle of a freshwater fish trypanosome from southern Africa and to do a morphological and molecular characterization of this parasite from both the fish host and leech vector. To locate trypanosome stages, leeches were removed from fishes captured in the Phongolo River, South Africa, and fish blood films and leech squashes were Giemsa-stained and screened. To determine whether trypanosome stages in fishes and leeches were of the same genotype, DNA was extracted and fragments of the 18S rDNA gene were amplified and sequenced. Trypanosomes were detected in the fish families Cichlidae, Clariidae, Mochokidae and Schilbeidae. Sequence data showed that the trypanosome from one of the leeches, identified as Batracobdelloides tricarinata (Blanchard, 1897), was highly similar to those obtained from the plain squeaker, Synodontis zambezensis, with 0.7% difference recorded between them. From morphological and molecular data presented here, it is clear that the trypanosomes from Phongolo are closely related to those of the Okavango and should be considered as a single diverse species with genetic differentiation between 0.4-2.9%, under the 3-5% differences expected to be seen between true distinct species within the rRNA. Developmental stages of the trypanosome found in the leech B. tricarinata supports its status as the vector and the molecular evidence shows the relationship between the trypanosome in the fish and leech, but also illustrates the exceptional genetic and morphological diversity of a single species of trypanosome between host species. The work presented here provides us with clear information to take further steps in resolving the taxonomy and systematics of African freshwater fish trypanosomes. [Abstract copyright: Copyright © 2020. Published by Elsevier Ltd.]

The reliance of parasites on their hosts makes host-parasite interactions ideal models for exploring ecological and evolutionary processes. By providing a consistent supply of parasites, in vivo monocultures offer the opportunity to conduct experiments on a scale that is generally not otherwise possible. Gnathiid isopods are common ectoparasites of marine fishes, and are becoming an increasing focus of research attention due to their experimental amenability and ecological importance as ubiquitous, harmful, blood-feeding "mosquito-like" organisms. They feed on hosts once during each of their three juvenile stages, and after each feeding event they return to the benthos to digest and moult to the next stage. Adults do not feed and remain in the benthos, where they reproduce and give birth. Here, we provide methods of culturing gnathiids, and highlight ways in which gnathiids can be used to examine parasite-host-environment interactions. Captive-raised gnathiid juveniles are increasingly being used in parasitological research; however, the methodology for establishing gnathiid monocultures is still not widely known. Information to obtain in vivo monocultures on teleost fish is detailed for a Great Barrier Reef (Australia) and a Caribbean Sea (US Virgin Islands) gnathiid species, and gnathiid information gained over two decades of successfully maintaining continuous cultures is summarised. Providing a suitable benthic habitat for the predominantly benthic free-living stage of this parasite is paramount. Maintenance comprises provision of adequate benthic shelter, managing parasite populations, and sustaining host health. For the first time, we also measured gnathiids' apparent attack speed (maximum 24.5 cm sec-1; 6.9, 4.9/17.0, median, 25th/75th quantiles) and illustrate how to collect such fast moving ectoparasites in captivity for experiments. In addition to providing details pertaining to culture maintenance, we review research using gnathiid cultures that have enabled detailed scientific understanding of host and parasite biology, behaviour and ecology on coral reefs.

Anurans from the genus Xenopus have long been used as standard testing organisms and occur naturally in tropical and sub-tropical areas where malaria vector control pesticides are actively used. However, literature on the toxic effects of these pesticides is limited. This review analyses the available data pertaining to both Xenopus and the pesticides used for malaria vector control in order to determine the pesticides that have the greatest potential to influence amphibian health while also identifying gaps in literature that need to be addressed. Amphibian diversity has shown the fastest decline of any group, yet there are still voids in our understanding of how this is happening. The lack of basic toxicity data on amphibians with regard to pesticides is an issue that needs to be addressed in order to improve effectiveness of amphibian conservation strategies. Meta-analyses performed in this review show that, at current usage, with the available acute toxicity literature, the pyrethroid pesticide group could hold the highest potential to cause acute toxicity to Xenopus sp. in relation to the other MVCPs discussed, but the lack of data cripples the efficacy with which meta-analyses can be performed and conclusions made from such analyses. Several studies have shown that DDT accumulates in Xenopus sp. from malaria vector control areas, but accumulation of other MVCPs in frogs is still largely unknown. Through this review we hope to encourage future research into the field of amphibian ecotoxicology and to promote the use of the Xenopus standard model in order to build comprehensive datasets that may be used in amphibian conservation.

Transmission electron microscopy (TEM) was used to study the ultrastructure of the uterus and egg morphology in the enigmatic bothriocephalidean tapeworm Tetracampos ciliotheca. The uterine wall, underlain by well-developed muscle bundles, consists of a syncytial epithelium which is characterized by the abundance of free ribosomes, mitochondria and cisternae of granular endoplasmic reticulum (GER). On the apical surface of the uterine epithelium, there is an abundant network of cytoplasmic microlamellae projecting into the uterine lumen. The lumen is filled with freely lying eggs which are located close to the uterine wall but do not contact with the microlamellae of the uterine epithelium. The developed eggs possess an oncosphere surrounded by four envelopes: (1) a thin egg shell; (2) an outer envelope; (3) a syncytial, ciliated inner envelope; and (4) the oncospheral membrane. The mature hexacanth is armed with three pairs of oncospheral hooks, as well as somatic and hook muscles and five types of cells (1) binucleated subtegumental cell, (2) somatic cells, (3) penetration gland cells, (4) nerve cells and (5) germinative cells. Considering the relative scarcity of descriptive and comparative studies on the ultrastructure of the uterus and egg morphology in the order Bothriocephalidea, we concluded that Tet. ciliotheca displays a unique type of egg development. Based on these results, we discuss plausible ideas relating to the function of these structures for consideration in future studies.

A new species of Grillotia Guiart, 1927 was recovered from the spotted skate (Raja straeleni Poll) from the south coast of the Western Cape, South Africa. Grillotia sasciae n. sp. is described based on morphological and molecular data. This species most closely resembles species in the subgenus Grillotia (viz., Grillotia borealis Keeney and Campbell, 2001, Grillotia brayi Beveridge and Campbell, 2007, Grillotia dollfusi Carvajal, 1971, Grillotia erinaceus Dollfus, 1969, Grillotia musculara Hart, 1936 and Grillotia patagonica Menoret and Ivanov, 2012) in having four hooks per principal row and intercalary hook rows in the metabasal region of the tentacular armature, a band of hooks on the external tentacular surface, numerous proglottids, and the presence of an uterine pore, a hermaphroditic sac, and internal and external seminal vesicles. The molecular phylogenetic analysis of the partial 28S rDNA gene, confirms the morphological data as it also groups Grillotia sasciae n. sp. within the G. erinaceus species complex. Grillotia sasciae n. sp. is distinctive among all other valid species in the complex by having two enlarged, uncinate hooks in the basal armature, of a different shape and size from the remaining hooks 1(1') in the metabasal armature. In addition, the retractor muscle of Grillotia sasciae n. sp. attaches at the posterior region of the tentacular bulb rather than the middle portion, continuing posteriorly as seen in most congeners (viz., G. erinaceus, G. borealis, G. brayi, G. musculara and G. pantagonica). The new species is the seventh species within the subgenus Grillotia and the first record of a species of Grillotia from southern African waters.