Thesis (M.S.)--Northern Michigan University, 2007. / Bibliography: leaves 103-110.

M.Sc. (Zoology) / Please refer to full text to view abstract

Rivers all over the world have supported the growth of human civilization since the first towns appeared some 7000 years ago. As a result of this growth and the diversification of activities, most of the world’s rivers have been negatively affected. Freshwater is probably the most important resource of mankind. Not only is it vital for terrestrial life but we consume water in such a range of activities that it can aptly be regarded as a ‘pillar of our civilization’. The development of water conservation recycling and management plans is therefore seen as vital. Cohen (1995) has recently highlighted the importance of freshwater to the future of mankind and in this context it is becoming increasingly important to view water as an economic resource in its own right. Being a third world country, South Africa is a developing country with a constant increase in population size. With the increase in the population, it is accompanied by increasing and expanding mining and industrial sectors. Various metals resulting from these sector’s activities are common pollutants in the rivers of South Africa. Although some metals are essential elements that are necessary for normal growth and metabolism in organisms, all metals can become toxic at elevated levels and therefore the monitoring of the freshwater systems is necessary in order to protect the environment and ultimately to protect humankind. Aquatic invertebrates appear to be excellent biological monitors of heavy metal pollution. They are more tolerant of metals than fish, they accumulate metals in relative proportion to the metal concentration in the water, and they concentrate the metal by some predictable, reproducible factor. However the life cycle of aquatic insects are short which limits the value in bioaccumulation studies. In contrast, crabs are relatively long lived and form an integral part of the food chain, as they are vital components in the diet of several animal species including humans. In the present study an integrated approach was employed in order to investigate the metal pollution in the Klip River, Gauteng. Selected physico-chemical characteristics of the water and sediment were analysed, as were the levels of metals bioaccumulated by the freshwater crab, Potamonautes warreni. Different biological aspects were investigated to identify the natural course of the life cycle, including moulting and reproductive cycles, relative abundance and age structure, as well as several behavioural patterns of this crab species. Water and sediment samples were collected from the Klip River and Sedaven Dam (reference locality) every month from August 1997 up to August 1998. Water quality data revealed that although the quality of the water at all sampling localities were relatively high, Lenasia (locality 1) and Dirk Fourie Stadium (locality 4) appeared to be more impacted than the rest of the sampling localities including the reference locality. Results of the metal analysis in the water samples indicated that levels of zinc, iron, manganese and chromium were below the suggested South African guideline values (laid down for the protection of aquatic life) and that elevated levels of cadmium, lead and aluminium were recorded at localities 1,3 and 4. Results of the metal analysis in the sediment samples indicated that there were elevated levels of zinc, lead, iron, manganese, chromium and aluminium at localities 1 and 2. Potamonautes warreni individuals were sampled every month to coincide with the water and sediment samples and the metal concentrations were determined. The results of this investigation showed that elevated levels of zinc, cadmium, lead, iron, manganese, chromium and aluminium was recorded at locality 1 and this indicated that this locality is subjected to above standard discharge. At locality 3 elevated levels of zinc, cadmium and chromium was recorded and at localities 4 and 5 elevated levels of iron and aluminium was recorded. The results of the present study indicates that metal levels in P. warreni are indicative of the environmental levels of metals to which these crabs are exposed. Higher metal levels as compared to the habitat were found in the organisms at all localities. Locality 1 had a higher environmental level than the rest of the localities. Therefore, these organisms are useful bioaccumulative indicators and should be incorporated into biomonitoring programs in conjunction with fish. It must be stressed that further studies be done on the mechanisms of regulation and elimination of certain metals from the body of P. warreni and on sublethal effects of metals on the physiological processes such as reproduction and growth, especially in juvenile crabs. / Prof. G.J. Steyn

M.Sc. / South Africa is a developing country in which the rapid increase in population size is accompanied by expanding mining and industrial sectors. All these factors have resulted in an increase in the demand for good quality water, but various anthropogenic activities continually result in pollution of the freshwater reserves in the country, via either diffuse or point sources. Metals resulting from both mining and industry are common pollutants of South African aquatic systems. Although some are essential elements that are necessary for normal growth and metabolism in organisms, all metals can become toxic at elevated levels, thus resulting in either lethal and sublethal effects. Aquatic organisms can also bioaccumulate metals thereby transferring them to their predators, including man. Monitoring of freshwater systems is thus necessary in order to protect the environment from these toxic substances, and ultimately to protect mankind. Most monitoring programmes should use an integrated approach in which both physico-chemical and biological aspects are monitored. The present study employed an integrated approach in order to investigate the state of metal pollution in two water bodies that are subjected to differential levels of metal contamination. Selected physico-chemical characteristics of the water and sediment were analysed, as were the levels of metals bioaccumulated by the Freshwater River crab, Potamonautes warreni. The specific object of this study was to assess the potential of P. warreni as a suitable bioaccumulative indicator of metal pollution in the aquatic environment. Water and sediment samples were collected from Germiston Lake and Potchefstroom Dam every alternate month between February 1995 and February 1996. Water quality data revealed that although the quality of the water at both sites was relatively high, Germiston Lake appeared to be more anthropogenically impacted than Potchefstroom Dam. Analysis of metal levels in the water and sediment indicated that while levels of copper, manganese, nickel, lead and zinc were higher in Germiston Lake, calcium and iron were present in higher concentrations in Potchefstroom Dam. Cadmium levels differed little between the two sites. With the exception of iron in Potchefstroom Dam, nickel in Germiston Lake, and zinc at both sites, all of the physical and chemical characteristics of the water from the two sites were within the boundaries of the South African guideline values laid down for the protection of aquatic life. Potamonautes warreni individuals were also collected every alternate month, and metal concentrations in these organisms were determined using atomic absorption spectrophotometry. The results of this investigation showed that metal levels in these organisms did tend to reflect those in the environment, with lower levels of calcium and iron and significantly higher (p < 0.05) levels of copper, manganese, lead, nickel, and zinc in P. warreni from Germiston Lake. Cadmium concentrations detected in these crabs were essentially the same at the two sites. All metals, except for cadmium, were influenced by the size of the crabs at one or other site, but never at both, thus suggesting that the presence of size-related trends is influenced by ambient metal levels in the system. Iron and lead concentrations in P. warreni from Potchefstroom Dam were the only metals that were influenced by the sex of the organisms, with higher levels found in female crabs. The results of the present study clearly indicate that metal levels in P. warreni are indicative of the environmental levels of metals to which these crabs are exposed since higher metal levels were found in the organisms from the site that had higher environmental metal levels. These organisms have proven to be useful bioaccumulative indicators of metal pollution in the aquatic environments from which they were captured, and they should therefore be incorporated into biomonitoring protocols. It must, however, be stressed that further research is required to increase our database on metal levels in these crabs from different aquatic systems.

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Freshwater organisms, such as crabs (Crustacea: Decapoda: Brachyura), are useful in studies examining inland historical biogeographic patterns and speciation because they are isolated to specific drainage systems, which often serve as barriers to gene flow. The Afrotropical freshwater crab fauna (Potamonautidae) present ideal organisms for investigating hypothesis relating to evolutionary histories because they occur on continental Africa (sub-Sahara) and islands. However, there is a great deal of undiscovered freshwater crab diversity, especially with the prevalence of undiscovered cryptic lineages, which are poorly studied among freshwater crabs, leading to uncertain regional diversity. In this research, multiple genetic (mt- and nuDNA) markers were used to infer the phylogenetic relationships and the biogeographical histories of the Afrotropical freshwater crab superfamily, Potamonautidae. Divergence time estimations were used to infer biogeographic histories, to ascertain whether speciation could be linked to past geologic and / or climatic events. Two widely distributed Potamonautes species complexes were targeted for the investigation of regional cryptic species diversity. In Chapter 2, the intraspecific phylogenetic variability within Potamonautes perlatus sensu lato occurring on the Cape Fold Mountain range (South Africa) was examined, with sampling localities occurring in western- and southern flowing drainages. Previous research suggested possible cryptic speciation within this species complex; however, no tangible inferences could be made because of analytical constraints. Two major clades were recovered: one corresponding to western flowing drainages and another to southern flowing drainages. Moreover, three cryptic lineages were recovered: P. perlatus sensu stricto, restricted to western flowing drainages, and two geographically discrete novel cryptic lineages from the southern flowing drainages, described as P. barbarai sp. nov and P. barnardi sp. nov., with divergence (±2.61 Mya) linked to Pleistocene climatic events. Subsequent to the recovery of the two novel lineages from the Cape Fold Mountain range, the Pleistocene climatic events. Subsequent to the recovery of the two novel lineages from the Cape Fold Mountain range, the revision of the P. clarus / P. depressus species complex from the Tugela and uMkomazi drainages (Drakensberg Mountain range, South Africa) was conducted. This species complex was previously found to comprise at least five cryptic lineages (Chapter 3). A coalescent multilocus (three mt- and three nuDNA) Bayesian species delimitation method was used, and an additional three cryptic lineages were recovered, bringing the total to eight species (two already described as P. clarus and P. depressus), with divergence having occurred approximately 10.3 Mya. Following the recent discovery of novel freshwater crab lineages in the mountainous areas of Mozambique and Malawi, a sampling trip to the Zimbabwean Highlands was undertaken, where a novel freshwater crab species was discovered and described as P. mutareensis, highlighting the need to sample high-lying regions (Chapter 4). Furthermore, two additional novel lineages from Mozambique (P. bellarussus sp. nov.) and the Mpumalanga Province in South Africa (P. flavusjo sp. nov) were described (Chapter 5). In Chapter 6, increased taxon sampling, with additional specimens acquired from various museums and personal collections was used to obtain a better resolution of the phylogeny of the Afrotropical Potamonautidae and to infer the ancestral affinities of the two sub-families, Deckeniinae and Potamonautinae. The Potamonautidae were found to have speciated eastward from West Africa, with a late Cretaceous divergence (±107 – 96.04 Mya). The Potamonautinae originated in West Africa (three genera), while the paraphyletic Potamonautes and Platythelphusa had East African affinities. Potamonautes was not monophyletic, comprising several fragmented geographic clades, which may suggest that this genus requires revision. Nevertheless, the overall speciation within the Potamonautidae reflects past geological and climatic events, such as rifting and uplift episodes and the contraction of forests, which occurred from the Tertiary onwards.

Thesis (PhD)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: In the present study, the systematic status, aspects of the evolutionary biology and phylogenetic relationships among species of the African freshwater crab genus Potamonautes in South Africa are examined. Systematic research between allopatric populations of P. brincki, using allozyme and morphometric data has revealed the existence of a new undescribed freshwater crab species occurring in mountain streams of the Cape Peninsula. This species is described in the present study. In addition, the diagnostic value of carapace dentition patterns in the taxonomy of freshwater crabs is explored among two toothed river crab species from South Africa. The latter study utilized P. warreni and P. unispinus where considerable variation in the dentition pattern of the former species has been recorded. Fixed differences in allozyme loci demonstrated that these two taxa should indeed be considered separate, yet closely related species, while the morphometric data failed to reveal this taxonomic separation. The holotype of P. warreni is re-described. The relationship of hybrid taxa between P. depressus and P. clarus populations are investigated. Evident from this study is that populations that occur equidistant from the two parental taxa have undergone extensive introgressive hybridization. Considering the pronounced sequence divergence and the occurrence of fixed allozyme loci between populations, it is postulated that the hybrid populations should be considered to be on a unique evolutionary trajectory worthy of conservation. The population genetic structure of P. calcaratus is examined as this species is unique in its occupation of water holes. Results demonstrate that the genetic population structure is the result of recent colonization and moderate gene flow among populations. Phylogenetic relationships between the southern African freshwater crab fauna is investigated with the use of sequence data from two mitochondial genes (12 S rRNA and 16 S rRNA), allozymes and morphology in an attempt to firstly, test the usefulness of freshwater crabs as biogeographic indicators, secondly to explore the relationship among hybrid taxa, and thirdly to examine Bott's (1955) subgeneric divisions. Results demonstrated that freshwater crabs can be used as biogeographic indicators, that hybrid taxa are phylogenetic ally closely related and that Bott's subgeneric divisions have no systematic basis. Among the three data sets, the sequence data provided the best resolution, while the phylogenetic inferences derived from the allozyme data and the morphology was limited. / AFRIKAANSE OPSOMMING: In hierdie studie word die sistematiek, aspekte van die evolusionêre biologie en filogenetiese verwantskappe tussen spesies van die varswater krap genus Potamonautes ondersoek in Suid Afrika. Navorsing op geografies geisoleerde populasies van P. brincki word met behulp van allosieme en morfometriese data ondersoek en dui daarop dat daar 'n nuwe onbeskryfde spesie op die berge van die Kaapse Skiereiland voorkom. Die nuwe spesies word beskryf in hierdie studie. Die diagnostiese waarde van tand patrone in varswater krappe word tussen twee spesies P. warreni en P. unispinus ondersoek. Genetiese data dui daarop dat alhoewel P. warreni morfologies baie naverwant is aan P. unispin us, is genoegsame verskille in allosiem lokusse wat daarop dui dat die twee taksa volwaardige spesies is. Die holotipe van P. warreni word herbeskryf. Die verwantkap tussen populasies van twee hibried taksa, P. depressus en P. clarus, word ondersoek. Resultate van hierdie studie dui daarop dat noemenswaardige verskille voorkom tussen die twee hibridie taxa en dat die hibriede populasies geneties verskillend is. 'n Argument word aangevoer vir die beskerming van hibriede taksa. Die populasie genetika van P. calcaratus word ondersoek en vergelyk met vorige studies. Die data dui daarop dat minimale geen vloei tusses populasies is en dat die populasie struktuur waarskynlik die resultaat is van onlangse kolonisasie. Die filogenetiese verwantskap tussen die suider Afrikaanse krappe word ondersoek met DNA, allosieme en morfologiese karakters met drie hoofdoele. Eerstens om die gebruik van varswater krappe as biografiese indikatore te toets. Tweedens om die verwantskap van hibriede taksa te ondersoek, en derdens om die status van Bott (1955) se subgenera te bepaal. Resultate dui daarop aan dat varswater krappe wel gebruik kan word as biografiese indikatore. Hibridieserende taxa naverwant is derdens en dat Bott se subgenera geen taksonomiese basis het nie. Die DNA data het die beste resolusie gebied vir die filogenetiese vrae, terwyl die allosieme en morfologiese data 'n laer resolusie bedied het, en meer beperk was.

Kingsleyini corresponde a uma das cinco tribos de Pseudothelphusidae, grupo exclusivamente americano de caranguejos de água doce. Atualmente a tribo inclui 59 espécies agrupadas em 13 gêneros, com distribuição associada aos rios, riachos e igarapés das bacias do Amazonas e do Orinoco. Desde a criação de Kingsleyini o aumento de novos táxons atribuídos a esta tribo não tem sido acompanhado por estudos cladísticos. No presente trabalho é realizada a análise cladística de Kingsleyini, acompanhada de uma revisão morfológica e taxonômica do grupo. Com este propósito, foram estudados espécimes de 60 espécies representantes das cinco tribos e duas subfamílias inclusas em Pseudothelphusidae. O material estudado se encontra depositado nas coleções carcinológicas de seis instituições e inclui os tipos nominais de 29 espécies. Na revisão morfológica foram descritas e ilustradas estruturas somáticas e sexuais da morfologia externa do grupo de estudo. Os estudos morfológicos foram auxiliados por técnicas de Microscopia Electrônica de Varredura (MEV) e cortes histológicos. A partir destas observações foram propostas modificações na terminologia utilizada para denominar as estruturas do primeiro apêndice sexual masculino (primeiro gonópodo) em Kingsleyini. A parte taxonômica deste trabalho inclui chaves de identificação, mapas de distribuição, listas sinonímicas e a descrição e ilustração do primeiro apêndice sexual masculino para a grande maioria das espécies examinadas, assim como a diagnose dos gêneros considerados monofiléticos. A análise filogenética foi realizada a partir de 92 caracteres obtidos de 57 táxons terminais: 49 terminais do grupo interno (Kingsleyini) e oito do grupo-externo (representantes dos demais Pseudothelphusidae). Como resultado da análise cladística foram obtidas seis hipóteses filogenéticas igualmente parcimoniosas: todas elas apoiam o monofiletismo de Kingsleyini e a exclusão do gênero Spirocarcinus da tribo. O monofiletismo dos gêneros Fredius, Kingsleya, Eudaniela e Rodriguezus também encontra-se sustentado em todas as hipóteses filogenéticas obtidas, enquanto que os gêneros Microthelphusa, Neopseudothelphusa, Orthothelphusa e Brasiliothelphusa revelaram-se parafiléticos. / Kingsleyini is one of the five tribes of Pseduthelphusidae, a American freshwater crabs family. Hitherto, this tribe includes 59 species and 13 genera with distribution associated to creeks and rivers of the Amazon and Orinoco basins. Since the establishment of Kingsleyini, the increase of new taxa attributed to the tribe has not been followed by cladistics studies. In this study, a phylogenetic analysis of Kingsleyini is provided, along with a morphological and taxonomic revision. With this aim, specimens of 60 species belonging the five tribes and two subfamilies comprising Pseudothelphusidae were studied. The specimens studied are housed in the carcinological collections of six institutions and included the nominal types of 29 species. In the morphological revision, somatic and sexual structures of external morphology were described and illustrated. Morphological studies were aided with Scanning Electron Microscope (SEM) techniques and histological sections. Based on these observations, some changes in the terminology of the first gonopod of Kingsleyini are proposed. The taxonomic part includes identification keys, distribution maps, synonymy lists, and descriptions and illustrations of the first gonopod for most species studied; along with diagnose for the genera considered monophyletic. For the phylogenetic analyses, 92 morphological characters were examinated for 57 taxa terminals: 49 ingroup (Kingsleyini) and eight outgroup (others pseudothelphusids). Six phylogenetic hypotheses equally parsimonious were retrieved: all supporting the monophyly of Kingsleyini, and the exclusion of Spirocarcinus of the tribe. The genera Fredius, Kingsleya, Eudaniela and Rodriguezus were supported as monophyletic groups, while Microthelphusa, Neopseudothelphusa, Orthotheplhusa and Brasiliothelphusa were retrieved as paraphyletic groups.

Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2007 / Urban rivers are the most utilised and yet degraded rivers worldwide. The urban rivers of the Western Cape are no different. The Lourens River flows through the agricultural and urban areas of Somerset West in the Western Cape and as a result is subjected to a variety of pollution sources. In the upper reaches this river flows through two large farms where metal containing pesticides are used. Further downstream it passes through an urban area where a variety of pollution sources could contribute to the contamination of the river. The extent to which the Lourens River, and the ecosystem it supports, is affected by metal pollutants is not known. The aim of this study was to determine the concentrations of metals in the Lourens River as well as the contribution of agricultural and urban activities to metal contamination of the river. Sediment and crab (Potamonautes perlatus) samples were collected over a period of one year from seven sites over the length of the river. Sediment samples were also collected from a sedimentation pond on the bank of the river where orchard run-off water is remediated. Preliminary analysis of samples was done for ten metals (AI, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb and Zn). Results from these analyses determined the selection of six metals (AI, Cr, Cu, Fe, Mn and Zn) for further investigation in this study. The concentrations of metals detected in collected samples varied significantly throughout the sampling period. This can be attributed to various factors such as rainfall patterns, the fact that pesticide application varies throughout the year and other urban activities. AI, Cr, Fe and Zn were found in significantly higher concentrations in the urban areas. These higher levels of contamination, relative to the upper parts of the river, can probably be attributed to various urban activities contributing to the contamination of run-off into the river. The sedimentation pond results revealed high concentrations of AI and Fe, while Cu, Cr, Mn, and Zn were found in lower concentrations. All six metals however followed the same pattern where the first four sampling occasions showed higher concentrations than the last three occasions. It can be concluded that agricultural and urban activities do contribute significantly to the metal contamination of the Lourens River.

Kingsleyini corresponde a uma das cinco tribos de Pseudothelphusidae, grupo exclusivamente americano de caranguejos de água doce. Atualmente a tribo inclui 59 espécies agrupadas em 13 gêneros, com distribuição associada aos rios, riachos e igarapés das bacias do Amazonas e do Orinoco. Desde a criação de Kingsleyini o aumento de novos táxons atribuídos a esta tribo não tem sido acompanhado por estudos cladísticos. No presente trabalho é realizada a análise cladística de Kingsleyini, acompanhada de uma revisão morfológica e taxonômica do grupo. Com este propósito, foram estudados espécimes de 60 espécies representantes das cinco tribos e duas subfamílias inclusas em Pseudothelphusidae. O material estudado se encontra depositado nas coleções carcinológicas de seis instituições e inclui os tipos nominais de 29 espécies. Na revisão morfológica foram descritas e ilustradas estruturas somáticas e sexuais da morfologia externa do grupo de estudo. Os estudos morfológicos foram auxiliados por técnicas de Microscopia Electrônica de Varredura (MEV) e cortes histológicos. A partir destas observações foram propostas modificações na terminologia utilizada para denominar as estruturas do primeiro apêndice sexual masculino (primeiro gonópodo) em Kingsleyini. A parte taxonômica deste trabalho inclui chaves de identificação, mapas de distribuição, listas sinonímicas e a descrição e ilustração do primeiro apêndice sexual masculino para a grande maioria das espécies examinadas, assim como a diagnose dos gêneros considerados monofiléticos. A análise filogenética foi realizada a partir de 92 caracteres obtidos de 57 táxons terminais: 49 terminais do grupo interno (Kingsleyini) e oito do grupo-externo (representantes dos demais Pseudothelphusidae). Como resultado da análise cladística foram obtidas seis hipóteses filogenéticas igualmente parcimoniosas: todas elas apoiam o monofiletismo de Kingsleyini e a exclusão do gênero Spirocarcinus da tribo. O monofiletismo dos gêneros Fredius, Kingsleya, Eudaniela e Rodriguezus também encontra-se sustentado em todas as hipóteses filogenéticas obtidas, enquanto que os gêneros Microthelphusa, Neopseudothelphusa, Orthothelphusa e Brasiliothelphusa revelaram-se parafiléticos. / Kingsleyini is one of the five tribes of Pseduthelphusidae, a American freshwater crabs family. Hitherto, this tribe includes 59 species and 13 genera with distribution associated to creeks and rivers of the Amazon and Orinoco basins. Since the establishment of Kingsleyini, the increase of new taxa attributed to the tribe has not been followed by cladistics studies. In this study, a phylogenetic analysis of Kingsleyini is provided, along with a morphological and taxonomic revision. With this aim, specimens of 60 species belonging the five tribes and two subfamilies comprising Pseudothelphusidae were studied. The specimens studied are housed in the carcinological collections of six institutions and included the nominal types of 29 species. In the morphological revision, somatic and sexual structures of external morphology were described and illustrated. Morphological studies were aided with Scanning Electron Microscope (SEM) techniques and histological sections. Based on these observations, some changes in the terminology of the first gonopod of Kingsleyini are proposed. The taxonomic part includes identification keys, distribution maps, synonymy lists, and descriptions and illustrations of the first gonopod for most species studied; along with diagnose for the genera considered monophyletic. For the phylogenetic analyses, 92 morphological characters were examinated for 57 taxa terminals: 49 ingroup (Kingsleyini) and eight outgroup (others pseudothelphusids). Six phylogenetic hypotheses equally parsimonious were retrieved: all supporting the monophyly of Kingsleyini, and the exclusion of Spirocarcinus of the tribe. The genera Fredius, Kingsleya, Eudaniela and Rodriguezus were supported as monophyletic groups, while Microthelphusa, Neopseudothelphusa, Orthotheplhusa and Brasiliothelphusa were retrieved as paraphyletic groups.