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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Distribution and ecology of aquatic pulmonate snails on a Wisconsin River flood-plain

Colburn, Elizabeth Anne, January 1975 (has links)
Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 89-95).
2

The biology and systematic status of Limax (Lehmannia) valentianus Férussac 1823

Westervelt, Clinton Albert, 1936- January 1961 (has links)
No description available.
3

An investigation of the biology and control of the Gray Garden Slug, Deroceras reticulatum (Müller).

Sivik, Frank Philip 01 January 1953 (has links) (PDF)
No description available.
4

Revisão taxonômica da malacofauna fóssil da Bacia de Itaboraí (Paleoceno), Rio de Janeiro / Taxonomic revision of the fossil molluscan fauna of Itaboraí Basin (Paleocene), Rio de Janeiro

Salvador, Rodrigo Brincalepe 06 December 2011 (has links)
As fácies calcárias da Bacia de Itaboraí, Rio de Janeiro, Brasil, são muito famosas por sua abundante fauna de mamíferos. Entretanto, Itaboraí também abriga uma rica fauna de gastrópodes pulmonados do Paleoceno Médio, tanto terrestres quanto dulciaquícolas. Contudo, os estudos lidando com essa malacofauna abrangem apenas as descrições originais das espécies. Nenhuma revisão taxonômica de maior escopo foi realizada nesses pouco mais de 80 anos desde a descoberta da bacia, embora seja possível identificar diversos problemas com a taxonomia desses fósseis. Desse modo, neste estudo realiza-se uma extensiva revisão taxonômica dessa fauna, descrevendo-se inclusive quatro novas espécies. Após a revisão, a nomenclatura e classificação dos pulmonados fósseis de Itaboraí encontram-se da seguinte maneira: Austrodiscus lopesi (Charopidae); Biomphalaria itaboraiensis e ? Vorticifex fluminensis (Planorbidae); Brachypodella britoi (Urocoptidae); Brasilennea arethusae, Brasilennea minor e Brasilennea sp. nov. (Cerionidae); Bulimulus fazendicus, Bulimulus sommeri, Bulimulus trindadeae, Cyclodontina coelhoi, Itaborahia lamegoi, Leiostracus ferreirai e Orthalicidae gen. nov. carvalhoi (Orthalicidae); Cecilioides sommeri (Ferussaciidae); Eoborus sanctijosephi, Eoborus sp. nov. 1, Eoborus sp. nov. 2 (Strophocheilidae); Gastrocopta mezzalirai, Gastrocopta sp. nov. (Vertiginidae); Temesa magalhaesi (Clausiliidae). A espécie Strobilopsis mauryae foi considerada sinônimo de Brasilennea arethusae. Além disso, relata-se pela primeira vez a ocorrência de ? Cyclodontina cf. (Plagiodontes) dentata para Itaboraí. A bacia conta com os registros fósseis mais antigos das famílias Ferussaciidae e Strophocheilidae. Além disso, os registros de Itaboraí das famílias Charopidae, Clausiliidae, Cerionidae, Orthalicidae, Urocoptidae e Vertiginidae estão entre os mais antigos do mundo. Dentre esses, os registros de Cerionidae, Clausiliidae e Urocoptidae merecem destaque por estarem bem afastados das distribuições atuais das famílias. Ademais, os registros de Itaboraí são os mais antigos para os gêneros Austrodiscus, Brachypodella, Cecilioides, Cyclodontina, Eoborus, Gastrocopta, Leiostracus e Temesa (além, é claro, dos três gêneros endêmicos da bacia, Brasilennea, Itaborahia e Orthalicidae gen. nov.). É surpreendente que um registro tão diverso quanto o de Itaboraí seja pouco explorado, uma vez que ele possui um grande potencial para ajudar a responder diversas questões sobre biogeografia e sistemática / The limestones of Itaboraí Basin, Rio de Janeiro, Brazil, are famous for their mammalian fauna. Nevertheless, Itaboraí also harbors a rich fossil molluscan fauna dating from the Middle Paleocene, consisting exclusively of pulmonate snails, both terrestrial and fresh-water. However, the current taxonomy of this fauna comprises only the original descriptions - there is not even a single more thoroughly revision done in the 80 years since the discovery of the basin. Unsurprisingly, many taxonomic problems could be readily identified. Therefore, an extensive taxonomic revision was conducted here, also describing four new species. After such revision work, the nomenclature and classification of Itaboraí\'s fossil pulmonates is as follows: Austrodiscus lopesi (Charopidae); Biomphalaria itaboraiensis e ? Vorticifex fluminensis (Planorbidae); Brachypodella britoi (Urocoptidae); Brasilennea arethusae, Brasilennea minor e Brasilennea sp. nov. (Cerionidae); Bulimulus fazendicus, Bulimulus sommeri, Bulimulus trindadeae, Cyclodontina coelhoi, Cyclodontina cf. (Plagiodontes) dentata, Itaborahia lamegoi, Leiostracus ferreirai e Orthalicidae gen. nov. carvalhoi (Orthalicidae); Cecilioides sommeri (Ferussaciidae); Eoborus sanctijosephi, Eoborus sp. nov. 1, Eoborus sp. nov. 2 (Strophocheilidae); Gastrocopta mezzalirai, Gastrocopta sp. nov. (Vertiginidae); Temesa magalhaesi (Clausiliidae). The species Strobilopsis mauryae was considered a synonym of Brasilennea arethusae. Also, the record of ? Cyclodontina cf. (Plagiodontes) dentata for the basin is presented here for the first time. Itaboraí Basin has the most ancient records of the families Ferussaciidae and Strophocheilidae. Moreover, the basin\'s records of the families Charopidae, Clausiliidae, Cerionidae, Orthalicidae, Urocoptidae and Vertiginidae are among the most ancient in the world. Among these, the records of Cerionidae, Clausiliidae and Urocoptidae deserve special attention for they are greatly removed from these families\' current distribution. Additionally, Itaboraí has the most ancient records for the genera Austrodiscus, Brachypodella, Cecilioides, Cyclodontina, Eoborus, Gastrocopta, Leiostracus and Temesa (besides, of course, the basin\'s three endemic genera: Brasilennea, Itaborahia and Orthalicidae gen. nov.). It is striking that such a diverse fossil fauna like Itaboraí\'s is so scarcely known, for it can potentially offer much help in biogeography and systematics
5

Revisão taxonômica da malacofauna fóssil da Bacia de Itaboraí (Paleoceno), Rio de Janeiro / Taxonomic revision of the fossil molluscan fauna of Itaboraí Basin (Paleocene), Rio de Janeiro

Rodrigo Brincalepe Salvador 06 December 2011 (has links)
As fácies calcárias da Bacia de Itaboraí, Rio de Janeiro, Brasil, são muito famosas por sua abundante fauna de mamíferos. Entretanto, Itaboraí também abriga uma rica fauna de gastrópodes pulmonados do Paleoceno Médio, tanto terrestres quanto dulciaquícolas. Contudo, os estudos lidando com essa malacofauna abrangem apenas as descrições originais das espécies. Nenhuma revisão taxonômica de maior escopo foi realizada nesses pouco mais de 80 anos desde a descoberta da bacia, embora seja possível identificar diversos problemas com a taxonomia desses fósseis. Desse modo, neste estudo realiza-se uma extensiva revisão taxonômica dessa fauna, descrevendo-se inclusive quatro novas espécies. Após a revisão, a nomenclatura e classificação dos pulmonados fósseis de Itaboraí encontram-se da seguinte maneira: Austrodiscus lopesi (Charopidae); Biomphalaria itaboraiensis e ? Vorticifex fluminensis (Planorbidae); Brachypodella britoi (Urocoptidae); Brasilennea arethusae, Brasilennea minor e Brasilennea sp. nov. (Cerionidae); Bulimulus fazendicus, Bulimulus sommeri, Bulimulus trindadeae, Cyclodontina coelhoi, Itaborahia lamegoi, Leiostracus ferreirai e Orthalicidae gen. nov. carvalhoi (Orthalicidae); Cecilioides sommeri (Ferussaciidae); Eoborus sanctijosephi, Eoborus sp. nov. 1, Eoborus sp. nov. 2 (Strophocheilidae); Gastrocopta mezzalirai, Gastrocopta sp. nov. (Vertiginidae); Temesa magalhaesi (Clausiliidae). A espécie Strobilopsis mauryae foi considerada sinônimo de Brasilennea arethusae. Além disso, relata-se pela primeira vez a ocorrência de ? Cyclodontina cf. (Plagiodontes) dentata para Itaboraí. A bacia conta com os registros fósseis mais antigos das famílias Ferussaciidae e Strophocheilidae. Além disso, os registros de Itaboraí das famílias Charopidae, Clausiliidae, Cerionidae, Orthalicidae, Urocoptidae e Vertiginidae estão entre os mais antigos do mundo. Dentre esses, os registros de Cerionidae, Clausiliidae e Urocoptidae merecem destaque por estarem bem afastados das distribuições atuais das famílias. Ademais, os registros de Itaboraí são os mais antigos para os gêneros Austrodiscus, Brachypodella, Cecilioides, Cyclodontina, Eoborus, Gastrocopta, Leiostracus e Temesa (além, é claro, dos três gêneros endêmicos da bacia, Brasilennea, Itaborahia e Orthalicidae gen. nov.). É surpreendente que um registro tão diverso quanto o de Itaboraí seja pouco explorado, uma vez que ele possui um grande potencial para ajudar a responder diversas questões sobre biogeografia e sistemática / The limestones of Itaboraí Basin, Rio de Janeiro, Brazil, are famous for their mammalian fauna. Nevertheless, Itaboraí also harbors a rich fossil molluscan fauna dating from the Middle Paleocene, consisting exclusively of pulmonate snails, both terrestrial and fresh-water. However, the current taxonomy of this fauna comprises only the original descriptions - there is not even a single more thoroughly revision done in the 80 years since the discovery of the basin. Unsurprisingly, many taxonomic problems could be readily identified. Therefore, an extensive taxonomic revision was conducted here, also describing four new species. After such revision work, the nomenclature and classification of Itaboraí\'s fossil pulmonates is as follows: Austrodiscus lopesi (Charopidae); Biomphalaria itaboraiensis e ? Vorticifex fluminensis (Planorbidae); Brachypodella britoi (Urocoptidae); Brasilennea arethusae, Brasilennea minor e Brasilennea sp. nov. (Cerionidae); Bulimulus fazendicus, Bulimulus sommeri, Bulimulus trindadeae, Cyclodontina coelhoi, Cyclodontina cf. (Plagiodontes) dentata, Itaborahia lamegoi, Leiostracus ferreirai e Orthalicidae gen. nov. carvalhoi (Orthalicidae); Cecilioides sommeri (Ferussaciidae); Eoborus sanctijosephi, Eoborus sp. nov. 1, Eoborus sp. nov. 2 (Strophocheilidae); Gastrocopta mezzalirai, Gastrocopta sp. nov. (Vertiginidae); Temesa magalhaesi (Clausiliidae). The species Strobilopsis mauryae was considered a synonym of Brasilennea arethusae. Also, the record of ? Cyclodontina cf. (Plagiodontes) dentata for the basin is presented here for the first time. Itaboraí Basin has the most ancient records of the families Ferussaciidae and Strophocheilidae. Moreover, the basin\'s records of the families Charopidae, Clausiliidae, Cerionidae, Orthalicidae, Urocoptidae and Vertiginidae are among the most ancient in the world. Among these, the records of Cerionidae, Clausiliidae and Urocoptidae deserve special attention for they are greatly removed from these families\' current distribution. Additionally, Itaboraí has the most ancient records for the genera Austrodiscus, Brachypodella, Cecilioides, Cyclodontina, Eoborus, Gastrocopta, Leiostracus and Temesa (besides, of course, the basin\'s three endemic genera: Brasilennea, Itaborahia and Orthalicidae gen. nov.). It is striking that such a diverse fossil fauna like Itaboraí\'s is so scarcely known, for it can potentially offer much help in biogeography and systematics
6

The conflict between adaptation and constraint : the case of the Siphonariid limpets

Chambers, Richard Jonathan January 1995 (has links)
The reproductive strategies of marine invertebrates have been related to various aspects of both their ecology, and their phylogenetic history. It has been the purpose of this thesis to try and separate these components among Siphonaria, a group of marine pulmonates. The taxonomy of these species is revised and I conclude that nine species are valid. All species deposit benthic egg masses and development may be either direct (S. anneae, S. compressa, S. dayi, S. nigerrima, S. serrata and S. tenuicostulata) or planktonic (S. capensis, S.concinna and S. oculus). Data on distribution and life-history relating to mode of larval development is then presented for 26 species of Siphonaria worldwide. Fifteen species are direct developers, nine are planktonic developers and a further two appear to have a dual developmental capacity, retaining both the velar swimming apparatus of a planktonic developer and the crawling foot of a direct developer. Direct developing species hatch from larger egg capsules, and generally occur higher on the shore than planktonic developers. Worldwide, planktonic developers are more widespread than direct developers, and individual planktonic species may have a greater latitudinal range. In most S~honaria subgenera, mode of larval development appears to be constant, although two subgenera (Patel/opsis and Sacculosiphonaria) include both developmental types. Locally, the intertidal zonation of three sympatric species (S. capensis, S. concinna and S. serrata) does not support a model which predicts direct development on the high shore and planktonic development on the low shore. However, distributions do correspond to particular intertidal microhabitats, and while there may be no, direct relationship between mode of larval development and intertidal height, the physical structure of egg masses, and the microhabitats used for spawning appear adaptive with regards to desiccation in the intertidal. S. concinna (planktonic development) and S. serrata (direct development) occur in similar microhabitats and are likely to be under similar selection pressures. In having different modes of larval development, there appears to be more than one optimal solution in a particular selective regime. In addition, both species seem to apportion similar amounts of energy to reproduction for each spawning episode, and also annually suggesting an optimum allocation of resources to reproduction. Genetic investigations using PolyAcrylamide Gel Electrophoresis (PAGE) confirm the status of the southern African species initially described, and indicate greater genetic variability associated with planktonic developing species than direct developing species. The systematic relationships revealed by DNA fingerprinting support the current classification systems, and also have implications with regards the evolution of larval development: direct development may be the plesiomorphic condition in, and among, some Siphonaria groups. There are both phylogenetic and adaptive explanations for the distribution of reproductive mode among benthic marine invertebrates. An evolutionary question, however, is not just a matter of either adaptation or constraint, it is a combination of these. Both contribute to the distribution of developmental mode among Siphonaria.
7

Environmental physiology of the intertidal limpets Patella (Prosobranchia) and Siphonaria (Pulmonata)

Marshall, David John January 1992 (has links)
Physiological response to environmental change is examined in species of the intertidal limpets, Patella (Prosobranchia) and Siphonaria (Pulmonata). Characteristics of heart beat were determined using impedance pneumography and these are described. Heart rate of P. granularis is related to temperature and body size, and cardiac arrest in this limpet is apparently stress-related. Siphonaria oculus may exhibit a temperature-independent, extreme, and often prolonged bradycardia (<10 beats/min). When measured shortly after aerial exposure, heart rate and oxygen consumption of the above limpet species are closely correlated. The relationships of aerial oxygen consumption with body weight and ambient temperature were determined for the above high shore species of limpet. Both have low aerial rates of oxygen consumption relative to low shore limpet species, and their QlO values decrease with increasing temperature. Diel field recordings of heart rate of S. oculus, taken during summer and winter, suggest absence of temperature acclimation, and this was also shown for oxygen consumption at high aerial temperatures (30°C) in laboratory experiments. Oxygen consumption of P. granularis is partially temperature compensated temperature acclimation). In air, even though S. oculus loses water faster, it shows greater tolerance of water loss and survives longer than P. granularis. Prolonged aerial exposure of S. oculus leads to depression of heart rate and of V02 (down to 18% of the pre-exposure rate), responses interpreted as representing adaptive metabolic rate depression. In P. granularis aerial heart rate remains constant and V02 never falls below IX 38% of pre-exposure rate. This reduction in V02 in air is considered as being stress-related, resulting from impairment of oxygen uptake. In declining oxygen tension S. capensis shows a better capacity for oxyregulation than P. granularis. On exposure to hypoxia, sand-inundation and hyposalinity, S. capensis may show typical bradycardia ( <10 beats/min), suggesting depression of aerobic metabolism, and on return to pre-exposure conditions there is no overshoot of heart rate, suggesting absence of oxygen debt. The effect of hypoxia, sand-inundation and hyposalinity on heart rate of P. granularis is variable; this becomes depressed and is often interspersed with extended cardiac arrest. When conditions are normalized, this species exhibits a clear overshoot of heart rate. The significance of differences in physiological response between patellid and siphonariid limpets is discussed with regard to their habitat segregation, particularly in the upper-shore zone (open rock and tidal pools) and sand-inundated rock substrata, where only siphonariid limpets may be found. While not previously characterized in marine gastropods, metabolic rate depression by Siphonaria, through facilitating isolation and conserving food reserves, is suggested as a key factor determining their distribution in physico-chemically more extreme and variable intertidal habitats.
8

Integrated strategies for investigating endocrine mechanisms in Biomphalaria glabrata as a test organism for androgenic chemical testing

Kaur, Satwant January 2015 (has links)
Endocrine and metabolic disease or dysfunctions are of growing concern in modern societies across the globe, underlining the need for continued focus on the development of pharmaceuticals. Subsequent scientific research has revealed a trend in the increase of such abnormalities and expansion of chemical industries, highlighting concerns that these disorders may, in part, be caused by exposure to environmental pollutants. This has led to changes in legislation concerning chemicals safety testing involving an increasing number of vertebrate animal tests as a part of environmental risk assessment process, at significant financial and ethical costs. A solution that is appropriate and aligned with the three R’s (reduction, refinement and replacement) in relation to animal research is to exploit the use of small invertebrate organisms as possible replacements for mammals. In line with the above approach/solution, this thesis is based on the null hypothesis that common genes, proteins and processes in gastropod molluscs and humans underlie the response of male reproductive organs to androgenic chemicals. Using a freshwater pulmonate snail, Biomphalaria glabrata, physiological effects of two steroid androgens on the development of mollusc secondary sexual organs were studied. Furthermore, an exhaustive investigation on the mollusc nuclear receptor repertoire and reproductive type neuropeptides was conducted. This also included the study of the evolutionary degree of conservation of these genes in non-model molluscs. The results obtained suggest that the snails did not respond to, and were not affected by exposure to the androgens. These results were supported by the absence of the members of subfamily 3C of nuclear receptors, which includes some of the “vertebrate” steroid hormone targets, suggesting that this mollusc may be an inappropriate model for steroid hormone mediated mammalian endocrine function. The nuclear receptor (NR) repertoire of B. glabrata comprised of 39 nuclear receptors representing all the known subfamilies of the NR superfamily. 21 reproductive type neuropeptide genes were identified encoding precursors that are predicted to release over 124 bioactive cleavage products. The consequence of these findings is significant in the context of the development of alternative model organisms for chemical testing as well as elucidating the taxonomic scope of nuclear receptor mediated endocrine disruption.
9

Genetic variation within two pulmonate limpet species, Siphonaria capensis and S. serrata along the South African coast

Seaman, Jennifer Ann January 2003 (has links)
Dispersal rates are known to play a fundamental role in establishing the genetic structure found within a species. Dispersal in marine benthic invertebrates is largely dependent on life history strategy. The presence of pelagic larvae will potentially result in high dispersal within a species, while direct development limits dispersal. This study used two intertidal pulmonate limpet species to investigate the relationship between dispersal potential and genetic structure of populations. Siphonaria capensis produces benthic egg masses, which release pelagic larvae. These float in ocean currents before settling and metamorphosing into adults. S. serrata reproduces by direct development. The larvae hatch as completely metamorphosed juveniles after developing in an egg case not far from the parent. The high dispersal capacity of S. capensis pelagic larvae should result in high levels of within-population variation since individuals within a particular population may originate from several different populations. This should lead to high levels of gene flow along the coast and to low genetic differentiation among populations. On the other hand, the low dispersal potential of S. serrata should cause low levels of genetic variation within populations, as relatives will remain close to one another. Low levels of gene flow and high genetic differentiation among populations are expected in this species. In dealing with the relationship between life history strategy and population genetic structure in these two species, a series of indirect techniques was utilised. Multivariate analyses of the morphological variation within each species showed that variation in size was similar between the two species and largely governed by environmental factors. Variation in shell shape was largely under genetic control and supported the predictions made for each species. Variation in total proteins was relatively uninformative in terms of examining the differences between the two species. Allozyme analysis and mtDNA sequencing clearly showed differences between the species in terms of their population genetic structure. High levels of gene flow were found within S. capensis. This was strongly influenced by ocean currents, with the close inshore Agulhas current along the Transkei coast contributing to high levels of dispersal and hence gene flow. Low levels of gene flow occurred within S. serrata, resulting in low within-population variation and high among-population differentiation.
10

Factors conditioning the distribution of fresh water pulmonates, <em>Biomphalaria </em>spp., <em>Bulinus </em>spp., and <em>Lymnea </em>spp., in Babati District, Tanzania.

Lydig, Anna January 2009 (has links)
<p>The aim of this essay was to investigate if different variables affected the distribution of fresh water pulmonate in Babati District, Tanzania. Can the absence of intermediate host be explained by basic vegetation evaluation, pH, conductivity and temperature? Or can it be explained by other factors as animals and vegetation in the surrounding? The study was carried out in Babati District, in Lake Babati, Kiongozi/Farahani River and the irrigation schemes in Matufa and Gichameda from the 23td of February until 7th of March, 2009. The species found during the survey were <em>Biomphalaria, Bulinus, </em>and <em>Lymnea. </em>Only <em>Biomphalaria pfeifferi </em>were present in the genus <em>Biomphalaria</em>. In <em>Bulinus </em>spp.<em>, B. globosus, B. forskalii, </em>and <em>B. africanus </em>were present. <em>Lymnea spp</em>. was represented by <em>L. natalensis</em>. Statistical tests were carried out with logistic models. The results of the statistical analysis revealed different significant results for the different snail species present. <em>L. natalensis </em>showed a significantly positive effect of the water temperature and was distributed in water temperatures ranging from 20.9°C to 24.3°C, which is in the lower range in this study. <em>Biomphalaria pfeifferi </em>and <em>Bulinus spp</em>. were significantly affected to an increase in conductivity. L. natalensis did show a significant effect of the type of bottom in the water body, and found muddy bottoms more suitable. Animal activity (livestock) did show a significant effect on the distribution of <em>L. natalensis </em>which found habitats without animals more suitable. Both <em>B. pfeifferi </em>and <em>L. natalensis </em>were significantly affected by vegetation in the surrounding and found habitats with grass, shrubs and trees more favourable before cultivated areas and forests. The statistical analysis made on the data collected in Babati District showed that temperature, conductivity, bottom in water body and vegetation in the surrounding, in general, significantly affected the fresh water pulmonate. Several variables as pH, water flow, canopy cover, vegetation in the water, however, were not significantly affecting the distribution of the snails. Further investigations of interactive effects of variables, however, are necessary to prevent high infection rates of trematodes infecting the pulmonate present in Babati District, Tanzania.</p>

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