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Radiolaria of the Bohemian Cretaceous Basin
Müllerová, Petra ; Holcová, Katarína (advisor) ; Vajskebrová, Markéta (referee)
The first part of work deals with cell structure, shell morphology, reproduction and nutrition. Also the ecology and systematical subdivision of radiolarians are described here. The systematical subdivision depends on differences in shell morphology of individual forms. The next part is devoted to Cretaceous radiolarians with focus on Cenomanian and Turonian ones, also some examples from several locations around the world is located here. The last part of this work deals with geology of Bohemian Cretaceous Basin, where the study of radiolarians from certain site will continue in master thesis.
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Evolution of silica structures in SAR protists
Čížková, Natálie ; Čertnerová, Dora (advisor) ; Kulichová, Jana (referee)
Silicon is an important element in the earth's crust. In nature it mainly occurs in the form of silicic acid. This element is used by marine and freshwater organisms to form their siliceous structures. The organisms that make up these structures are located throughout the phylogenetic tree and are not limited just to protist groups. The SAR line includes Stramenopila, Alveolata and Rhizaria. The main protist taxa forming the mentioned siliceous structures are in these groups. These are mainly diatoms, silicoflagellates, radiolarians and the group chrysophyceae. The formation of siliceous structures usually provides evolutionary benefits to organisms, such as protection of the cell from actions of biotic and abiotic factors. The availability of dissolved silicon changed during evolution, thus affecting the appearance and functionality of the structures of individual species. Structural changes were manifested by thinning of the shells, change of cell size, enlargement or decrease of pores, increase of the number of thorns or, conversely, their loss. The individual lines thus had to choose the best possible strategies in response to the decreasing availability of silicic acid. Therefore, there was frequent competition between the groups for the remaining dissolved silicon. The current diversity of...
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Cretaceous Radiolaria from the Březno section
Müllerová, Petra ; Holcová, Katarína (advisor) ; Vajskebrová, Markéta (referee)
The presented thesis is focused on the Radiolaria of the Czech Cretaceous Basin. The studied material was collected in Březno u Loun and in the Úpohlavy quarry. Biology, ecology and morphology, as well as systematics of the whole group is discussed. An important part of this thesis constitutes of the geological settings of Cretaceous, Czech Cretaceous Basin and both localities. 26 samples from Březno and 24 samples from the Úpohlavy quarry have been studied using several methods with the aim to obtain most numerous and best preserved communities possible. Despite poor preservation of the shells, 9 species have been identified. Several shells have been assigned at least to the genus or order levels. Species of Dictyomitra communis (Squinabol, 1904), Dictyomitra cf. napaensis Pessagno, 1976, Turbocapsula cf. giennensis O'Dogherty, 1994, Novixitus cf. mclaughlini Pessagno, 1977, Stichomitra cf. stocki (Campbell & Clark, 1944), Stichomitra communis Squinabol, 1903, Stichomitra japonica (Nakaseko & Nishimura), in Nakaseko et. al., 1979, Holocryptocanium barbui Dumitrica, 1970, cf. Pseudoaulophacus pargueraensis Pessagno, 1963 and genera of Orbiculiforma, Stichomitra, cf. Cryptamphorella have been reported in the Czech Cretaceous Basin for the first time.
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Radiolaria of the Bohemian Cretaceous Basin
Müllerová, Petra ; Vajskebrová, Markéta (referee) ; Holcová, Katarína (advisor)
The first part of work deals with cell structure, shell morphology, reproduction and nutrition. Also the ecology and systematical subdivision of radiolarians are described here. The systematical subdivision depends on differences in shell morphology of individual forms. The next part is devoted to Cretaceous radiolarians with focus on Cenomanian and Turonian ones, also some examples from several locations around the world is located here. The last part of this work deals with geology of Bohemian Cretaceous Basin, where the study of radiolarians from certain site will continue in master thesis.
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