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Book
Parasitic Crustacea : State of Knowledge and Future Trends
Authors: --- ---
ISBN: 3030173852 3030173836 Year: 2019 Publisher: Cham : Springer International Publishing : Imprint: Springer,

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Abstract

This book offers the first comprehensive review of parasitic Crustacea, which are among the most successful and diverse parasites. Starting with an introductory chapter, followed by an historic overview and topic-specific chapters, each presenting a different aspect of parasitic crustacean biology, it enables readers to gain a better understanding of how these parasites function and allows direct comparisons between the different parasitic crustacean groups. The authors also discuss, in depth, the adaptations and interactions that have made parasitic Crustacea as successful as they are today, covering topics ranging from the history of their discovery, their biodiversity, phylogeny, evolution and life strategies to their role as vectors, or hosts of other organisms, and their significance in ecological processes. Consisting of ten chapters from leading international experts in the field, this volume offers a one-stop resource for all researchers, lecturers, students and practitioners.


Dissertation
Impact of Prolonged and Seasonal Drought on the Aquatic Invertebrate and Diatom Communities in Nyamithi Pan

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Organisms that live on the floodplain of a river need sufficient water to survive. When the river dries up during a dry period, organisms will be affected although they are generally able to handle such periods and may recover quickly. Not much is known about what happens to the organisms when such a drought lasts longer and is more intense than usual. This is important to understand because when the organisms on the floodplain are negatively impacted, overall biodiversity is in danger. Ultimately, this will have an impact on humans as well because the services that the floodplain provides, such as fertile soils for agriculture, supply of fish and wood will decline. Therefore, this study looked at the effects of a long dry period in 2014-2016 on the aquatic organisms. The study area was lake Nyamithi in the Ndumo Game Reserve (NGR), which lies on the Phongolo floodplain in South Africa. Under normal circumstances this lake receives flood water largely from the Phongolo River through annual controlled flood releases from the Pongolapoort dam located upstream of the river as well as natural floods from the Usuthu River. However, due to an El Niño event no floods have been released from the Phongolo River since December 2014. The organisms that were collected in Nyamithi were macroinvertebrates, zooplankton and diatoms. Macroinvertebrates and zooplankton were collected during nine occasions from September 2014 to November 2017. Diatoms were collected during three occasions from February 2017 to August 2017. Sediments of the lake were sampled once in November 2017. Water quality in Nyamithi decreased overall in the dry period as the water became saltier. The results of this study show that biodiversity of macroinvertebrates and zooplankton was higher before the drought began. During the drought, very different species were found than during the wet period. In 2017 there was a partial recovery of the macroinvertebrates and zooplankton due to flooding of the Usuthu River, meaning species that were present before the drought slowly started to reappear again. A full recovery will probably require a flood release from the Pongolapoort dam into the Phongolo River. Eggs of zooplankton that were found in the sediment of the lake showed that species used to be present that normally live in freshwater and fluctuating conditions. The diatoms were not affected as much because the water remained saline throughout the different sampling occasions in 2017. Future research should continue to collect samples to understand how long it might take for the organisms to recover completely. On the short-term, the conditions in Nyamithi will improve as the drought will subside and the Phongolo River will start flooding again. However, on the long-term, climate change may negatively impact the floodplain because droughts will become more frequent. In addition, human activities such as the construction of dams on rivers and abstraction of water from them make it harder to these systems to recover from disturbance such as drought.

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Dissertation
Ecology, systematics and evolutionary biology of frog blood parasites in northern KwaZulu-Natal
Authors: --- --- --- --- --- et al.
Year: 2019 Publisher: Leuven Potchefstroom KU Leuven. Faculty of Science North-West University. Faculty of Natural and Agricultural Sciences

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Blood parasites have been recorded in a variety of vertebrate and invertebrate hosts, inhabiting both aquatic and terrestrial environments. Until this study, only a few blood parasite surveys had been carried out on frogs in sub-Saharan Africa. Thus information on the diversity of these parasites remained limited. To increase our knowledge of frog blood parasites, a large multi-approach study on the diversity, evolutionary biology, and ecology of frog blood parasites was undertaken. The majority of the fieldwork took place in northern KwaZulu-Natal (KZN), South Africa, focussing specifically on the area adjacent to the Phongolo River and its associated floodplain. However, samples also included those collected from frogs in the southern regions of the Kruger National Park, South Africa, and from frogs in Belgium. The latter was fortuitous, as Europe is the type locality for many frog blood parasite species and genera. These samples provided essential data for phylogenetic comparisons between the African and European species. Presently this is the largest multi-species, generic and family amphibian blood parasite survey to be completed, including a total of 643 anurans of 38 species, 20 genera and 13 families. The study was divided into three main components for the collection, analysis and reporting of data. The first component was to determine the frog blood parasite diversity, the second to determine phylogenetic relationships in conjunction with the former component, and lastly the ecological and host-vector-parasite relationships. Blood samples were drawn from the femoral artery of each frog and thin blood smears prepared for screening and morphometrics; the remaining blood fixed in 70% molecular grade EtOH for later molecular analysis. Giemsa stained blood smears were screened microscopically for the presence of any blood inhabiting organisms. Positive infections were then further analysed according to the aims of the respective chapters. Analyses included both morphological and molecular aspects. Morphology was used for the description and identification of species, and molecular analyses were used to assist with the morphology-based descriptions, as well as to allow for phylogenetic relationship comparisons of the blood parasites with one another.In the present study, three new species of Hepatozoon were described from hyperoliid frogs (Afrixalus fornasini, Hyperolius argus, and Hyperolius marmoratus), namely Hepatozoon involucrum Netherlands, Cook & Smit, 2018; Hepatozoon tenuis Netherlands, Cook & Smit, 2018; and Hepatozoon thori Netherlands, Cook & Smit, 2018. Phylogenetic relationships show that species of Hepatozoon isolated from African frogs form as a monophyletic group, separate from the species of Hepatozoon isolated from European and North American frogs. Two species of Dactylosoma Labbé, 1894, were found parasitising three species of frogs namely, Ptychadena anchietae and Sclerophrys gutturalis from South Africa, as well as Pelophylax lessonae from Belgium. Based on morphometrics and molecular findings a new dactylosomatid, Dactylosoma sp. 1, is described form Pty. anchietae and Scl. gutturalis. The species of Dactylosoma isolated from Pel. lessonae conforms morphologically with Dactylosoma splendens Labbé 1894, thus placing in question the validity of D. splendens synonymy with D. ranarum (Kruse, 1890). Phylogenetic analysis shows species of anuran Dactylosoma as a monophyletic group, separate from the other haemogregarine groups. Five species of frogs from South Africa and two from Belgium were found parasitised with haemococcidia. Based on morphological, morphometric and molecular findings Lankesterella minima (Chaussat 1850) is redescribed from Pelophylax kl. esculentus (Linnaeus, 1758) and Pel. lessonae (Camerano, 1882) from Belgium. Additionally, two new species of Lankesterella were described, namely Lankesterella sp. 1 in Pel. lessonae from Belgium, and Lankesterella sp. 2 in Afr. delicates and Afr. fornasini from South Africa. Furthermore, a new genus of haemococcidia, with a new species combination, is described from Phr. mababiensis, Pty. anchietae, and Pyx. edulis from South Africa; as well as a new species, haemococcidia sp. 2, described from Afr. fornasini from South Africa. This is the first study to provide molecular data for species of haemococcidia from African and European anurans.A new species of amphibian filarial nematode (Onchocercidae: Waltonellinae) was described from the toads Scl. gutturalis and Scl. garmani. The life history of this nematode was elucidated from its natural mosquito vectors Uranotaenia (Pseudoficalbia) mashonaensis and Uranotaenia (Pfc.) montana. All stages of development were characterised using morphological and molecular methods. This study is the first to elucidate the life history of an amphibian filarial nematode from southern Africa, and provide data on its phylogenetic placement within the Onchocercidae. In addition to the taxonomic and phylogenetic perspective of this study, this study also aimed at exploring the potential of frog blood parasites as indicators of environmental health. For this, blood parasites infecting grass frogs (Ptychadena Boulenger, 1917) from the Phongolo River system in South Africa were used as a case study. In general, findings indicate that frogs from more impacted sites harboured more blood parasites than from less-impacted sites.In summary, this study explored the efficacy of a large multi-species, multi-approach survey on the diversity of frog blood parasites from northern KwaZulu-Natal, South Africa. Based on the results several new species of frog blood parasites from different taxa were discovered and described, greatly contributing to knowledge and species records on the overall diversity of frog blood parasites from South Africa. Furthermore, this study provides the first molecular data for species of Dactylosoma and Lankesterella for frogs from Africa, as well as the first molecular data for a filarial nematode for frogs from South Africa. The phylogenetic relationships of species of Hepatozoon, Dactylosoma, Lankesterella, and the filarial nematode were also characterised based on comparisons to other available molecular data. From an ecological perspective, blood parasites from this study adhere to several criteria of what is considered a good indicator and thus demonstrate potential as indicators for healthy ecosystems and intact food webs. The results of this study establish a foundation for future research into the blood parasite biodiversity in northern KZN, an area that this study has highlighted as not only rich in anuran diversity, but also rich in anuran blood parasite diversity. Furthermore, this study provides a baseline for future taxonomic and ecological studies on these parasite groups, not only in South Africa but globally as well.

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