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Diversity of freshwater epigean amphipods
Rutová, Tereza ; Petrusek, Adam (advisor) ; Sacherová, Veronika (referee)
Gammarids, the most diverse group of Amphipoda are present in marine, brackish and fresh waters. In freshwater there are forms inhabiting the surface (epigean) and underground (hypogean) habitats and this thesis will be focused on epigean freshwater groups. Freshwater gammarids inhabit the continental waters of all continents, but the highest species diversity is evident in the Palearctic region. However they cannot be found in the surface waters of the tropical regions. These amphipods are characterized by the absence of any resistant or larval stages. Thus the present diversity and distribution reflects historical events like the fluctuation in sea levels, orogeny or period of glaciation from the Paleocene to the present. The goal of this thesis will be to summarize which processes and in which period the diversity of freshwater epigean amphipods were affected. One part of this thesis is dedicated to the families occurring in Australia (Chiltonidae), New Zealand (eg. Phreathogammaridae) and the North and the South America (Hyalellidae). The main focus is on family Gammaridae in which according to recent studies should include lineages occurring in the entire Palearctis including endemic groups in the Lake Baikal and across the Ponto-Caspian area. In the history of the development of gammarids...
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Habitat and pairing preferences among coexisting lineages of the Gammarus fossarum species complex in the Western Carpathians
Bystřický, Pavel Karel ; Petrusek, Adam (advisor) ; Čiampor, Fedor (referee)
In recent years, due to the development of molecular methods, a great level of cryptic diversity across multiple taxa was discovered. One of these groups are freshwater amphipods. Amphipods due to lower dispersal and recolonization abilities present a suitable model system for studying potential ecological interactions among genetically distant lineages during their secondary contact. In this thesis, I studied the cryptic species complex Gammarus fossarum in a contact zone of several genetically divergent lineages known from the previous research in the Vsetin region. I focused on two main questions: Firstly, whether there are preferences among individuals from different lineages for sexual partners from the same lineage rather than from the different one (i.e., I test for the potential existence of prezygotic reproduction barrier between the lineages). I tested this hypothesis by collecting pairs from natural contact zone and also (in a limited extent) by an aquarium experiment. Secondly, I tested whether these lineages differ in mesohabitat (pool versus riffle) distribution in syntopy, which may indicate competition among lineages and potential diversification of their ecological niches. Animals from nine localities (with expected contact of two lineages per locality) were examined. In more than...
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Ecological interactions and niche differentiation of coexisting freshwater amphipods
Bystřický, Pavel Karel ; Petrusek, Adam (advisor) ; Pařil, Petr (referee)
Freshwater amphipods are ecologically important crustacean group. They act mainly as shredders of detritus in fast-running and cold waters, contributing to the nutrient cycles. Ecological interactions within this group are interesting especially in connection with a considerable degree of cryptic diversity, as well as due to contacts of invasive and native species. This thesis deals with so far studied interactions between syntopic species or lineages, especially those that may affect coexistence or competitive exclusion, such as: different levels of selective predation, ecologically significant differences in morphology or behavior, varying degrees of aggressiveness or intraguild predation, and differences in habitat preferences or resource use ability. Due to the large number of newly discovered cryptic lineages, only little effort has been invested to studies of their ecological interactions. For the time being, research has been limited to sexual interactions (potential reproductive interference or hybridization), differences in habitat preferences, or infestation rates by parasites. It is worth mentioning that only a few lineages have been explored in this way, and the lessons learned from these few works cannot yet be generalized. In my work, I focus on cryptic species complexes in which at...
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Systematics of the genus Ramariopsis (Basidiomycota, Clavariaceae) in central Europe
Matouš, Jan ; Holec, Jan (advisor) ; Kučera, Viktor (referee)
The genus Ramariopsis (Clavariaceae, Agaricales) having ramarioid, rarely clavarioid basidiomata includes about 15 species in central Europe. They are probably saprotrophic species which usually occur in grasslands or rarely open places in shrubs or deciduous forests. In this work, 88 collections of this genus mainly from the Czech Republic and Slovakia were studied, of which 57 sequences from the LSU and 36 from the ITS regions of the nuclear ribosomal RNA gene complex were obtained. Based on molecular-phylogenetic analyses using the maximum likelihood and bayesian methods, phylogenetic trees were created showing 16 well-supported clades. So detailed study on the phylogeny and relationships among species of the genus Ramariopsis is presented for first time, even within the world literature. Subsequent morphological analysis supported by SEM study of basidiospores showed that obtained clades represent nine species known in taxonomic literature, three so far non-described species (that were labelled with provisional names) and four clades whose interpretation is uncertain at the moment. Thus, seven clades represent cryptic diversity, which is a rather high extent. A new species Ramariopsis robusta Matouš et Holec has already been published and Ramariopsis rufipes and Ramariopsis kunzei var. bispora...
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Diversity of freshwater epigean amphipods
Rutová, Tereza ; Petrusek, Adam (advisor) ; Sacherová, Veronika (referee)
Gammarids, the most diverse group of Amphipoda are present in marine, brackish and fresh waters. In freshwater there are forms inhabiting the surface (epigean) and underground (hypogean) habitats and this thesis will be focused on epigean freshwater groups. Freshwater gammarids inhabit the continental waters of all continents, but the highest species diversity is evident in the Palearctic region. However they cannot be found in the surface waters of the tropical regions. These amphipods are characterized by the absence of any resistant or larval stages. Thus the present diversity and distribution reflects historical events like the fluctuation in sea levels, orogeny or period of glaciation from the Paleocene to the present. The goal of this thesis will be to summarize which processes and in which period the diversity of freshwater epigean amphipods were affected. One part of this thesis is dedicated to the families occurring in Australia (Chiltonidae), New Zealand (eg. Phreathogammaridae) and the North and the South America (Hyalellidae). The main focus is on family Gammaridae in which according to recent studies should include lineages occurring in the entire Palearctis including endemic groups in the Lake Baikal and across the Ponto-Caspian area. In the history of the development of gammarids...
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Molekulárně-fylogenetická charakteristika izolátu Hymenolepis diminuta udržovaného v laboratorních podmínkáh
ŘEŽÁBKOVÁ, Lucie
The main goal of the present study was to confirm the possibility of cryptic diversity within Hymenolepis diminuta group of tapeworms. We used molecular-fylogenetic analyses for characterization of the intraspecific genetic diversity of five isolates of Hymenolepis diminuta. Further, we wanted to compare our isolate of H. diminuta that is tested for purposes of the helminth therapy with other isolates obtained from collaborative institutions. Our results showed no cryptic diversity within H. diminuta clade of the five isolates and confirmed that our isolate is really H. diminuta previously characterized only based on its morphology.
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