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Evoluionary dynamics of NORs in pseudoscorpions (Arachnida: Pseudoscorpiones)
Šilhavá, Alena ; Šťáhlavský, František (advisor) ; Symonová, Radka (referee)
From the karyological point of view, pseudoscorpions are still a little known organisms. Until now, karyotypes of only 61 species from eight families were described, while the distribution of the nucleolar organizers is only known from a single species. Pseudoscorpions' karyotypes exhibit considerable variability in diplopid number and in morphology of the chromosomes, and, as this thesis presents, a large variability in the number and position of NORs. The diploid number in pseudoscorpions ranges from seven to 143. In this study, 68 species from 19 families were analyzed, of which karyotypes of nine families are described here for the first time. In other four previously studied families, the ranges of diploid numbers were extended. For the detection of 18S rDNA clusters, we used fluorescence in situ hybridisation (FISH) to localize NORs. Apparently the number of 18S rDNA clusters can change very dynamicaly in some Gross (e.g. one to nine pairs in Chthoniidae). Furthermore, I observed variability in the position of detected clusters, which were often found terminally on chromosomes; a position considered ancestral for arachnids. The changes in number and position of 18S rDNA clusters of the analyzed taxa could, in some cases, be related to the hypothetical chromosomal rearrangements. The most...
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Evoluionary dynamics of NORs in pseudoscorpions (Arachnida: Pseudoscorpiones)
Šilhavá, Alena ; Šťáhlavský, František (advisor) ; Symonová, Radka (referee)
From the karyological point of view, pseudoscorpions are still a little known organisms. Until now, karyotypes of only 61 species from eight families were described, while the distribution of the nucleolar organizers is only known from a single species. Pseudoscorpions' karyotypes exhibit considerable variability in diplopid number and in morphology of the chromosomes, and, as this thesis presents, a large variability in the number and position of NORs. The diploid number in pseudoscorpions ranges from seven to 143. In this study, 68 species from 19 families were analyzed, of which karyotypes of nine families are described here for the first time. In other four previously studied families, the ranges of diploid numbers were extended. For the detection of 18S rDNA clusters, we used fluorescence in situ hybridisation (FISH) to localize NORs. Apparently the number of 18S rDNA clusters can change very dynamicaly in some Gross (e.g. one to nine pairs in Chthoniidae). Furthermore, I observed variability in the position of detected clusters, which were often found terminally on chromosomes; a position considered ancestral for arachnids. The changes in number and position of 18S rDNA clusters of the analyzed taxa could, in some cases, be related to the hypothetical chromosomal rearrangements. The most...
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Biogeography of arachnofauna of the Alps
Šilhavá, Alena ; Šťáhlavský, František (advisor) ; Řezáč, Milan (referee)
This bachelor thesis gives a summarizing overview of the biogeography of arachnofauna of the Alps. It covers five orders of arachnids residing in the Alps, namely scorpions (Scorpiones), pseudoscorpions (Pseudoscorpiones), palpigrades (Palpigradi), harvestmen (Opiliones) and spiders (Araneae). The work is focused on the distribution of endemic and subendemic species of these orders of arachnids and on factors that can influence their distribution and total diversity in the Alps. It turns out that temperature and humidity are important factors. Pseudoscorpions occur more frequently in warmer areas at lower altitudes, while especially scorpions of the genus Euscorpius (Alpiscorpius) and harvestmen are more tolerant to areas with a lower temperature, while harvestmen especially require sufficient humidity. For spiders in the mountains of the Alps total species richness and density decreases mainly from open land to the forest. Total diversity in the Alps has also been influenced by temperature oscillations during the Quaternary climatic changes and different positions and types of refugia. This is apparent at the species closely related to soil environment, such as palpigrades or cave pseudoscorpions of the family Syarinidae. Key words: biogeography, the Alps, endemic, Scorpiones, Pseudoscorpiones,...
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