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Teraz sa zobrazuje 1 - 5 z 5
  • Položka
    Čo sa môžeme naučiť z (paleo)limnologického výskumu jazier Strednej Ameriky?
    (Limnologický spravodajca, Slovak Limnological Society, 2017-02) Hamerlík, Ladislav
  • Položka
    First record of the genus Heterotrissocladius (Chironomidae: Orthocladiinae) from the Neotropical Region
    (NTNU University Museum, Norway, 2018) Hamerlík, Ladislav; Da Silva, Fabio Laurindo
    Here we report the occurrence of Heterotrissocladius (Diptera: Chironomidae: Orthocladiinae) for the first time in Central America, as well as in the Neotropical region. The report is based on sub-fossil chironomid head capsules from surface sediments of a high elevation lake, Lago Magdalena, Guatemala.
  • Položka
    Chironomidae (Insecta: Diptera) of Ecuadorian high altitude streams: a survey and illustrated key
    (Florida Entomological Society, 2018) Hamerlík, Ladislav; Da Silva, Fabio Laurindo; Jacobsen, Dean
    Chironomidae (Diptera) are among the most diverse and widespread aquatic insects, with roughly 5,500 described species inhabiting an enormous variety of aquatic ecosystems, ranging from moist soils to lakes and rivers, and even marine ecosystems. Despite its ubiquity, the group remains underrepresented in studies addressing aquatic insect assemblages of high-altitude systems, either glacier-fed or non-glacial, particularly in South America. Glacier-fed streams possibly are one of the harshest ecosystems in nature, and present a distinct downstream pattern in species distribution and diversity away from the constraining influence of the glacier. In this context, the goal of our study was to provide data on the chironomid fauna of glacier-fed streams, together with neighboring non-glacial streams in Ecuador, in order to contribute to the overall knowledge of tropical fauna in high Andean regions. Also, we sought to provide an identification key and photography material for future studies. Collections of non-biting midges were made in Ecuador during Jan 2008. In total, 1,412 specimens belonging to 16 genera and at least 23 species within the subfamilies Chironominae (3 taxa), Diamesinae (3 taxa), Podonominae (3 taxa), Orthocladiinae (13 taxa), and Tanypodinae (1 taxon) were found. The subfamilies Podonominae and Orthocladiinae predominated in terms of abundance. Parochlus was the most widespread genus of Chironomidae, while Cricotopus was the most diverse. This study contributes to the knowledge of the chironomid fauna in the high-altitude streams in Ecuador, and hopefully will motivate further studies in the area.
  • Položka
    Sub-fossil Chironomidae (Diptera) from lake sediments in Central America: a preliminary inventory
    (Zootaxa, Magnolia press, 2018) Hamerlík, Ladislav; Da Silva, Fabio Laurindo; Wojewódka, Marta
    The chironomid diversity of Central America is virtually underestimated and there is almost no knowledge on the chironomid remains accumulated in surface sediments of lakes. Thus, in the present study we provide information on the larval sub-fossil chironomid fauna from surface sediments in Central American lakes for the first time. Samples from 27 lakes analysed from Guatemala, El Salvador and Honduras yielded a total of 1,109 remains of four subfamilies. Fifty genera have been identified, containing at least 85 morphospecies. With 45 taxa, Chironominae were the most specious and also most abundant subfamily. Tanypodinae with 14 taxa dominated in about one third of the sites. Orthocladiinae were presented by 24 taxa, but were recorded in 9 sites, being dominant in only one site. Podonominae were collected only in one locality. Head capsules of Heterotrissocladius found in the high elevation lake Magdalena, Guatemala, represent a first record for the Neotropical region. Both relative abundance and species richness of Chironominae and Orthocladiinae showed significant relationship to elevation, while Tanypodinae were indifferent. Hopefully, the list of taxa provided by our study will be a base line for future limnological and paleolimnological investigations using chironomid remains in the region.
  • Položka
    Subfossil Chironomidae (Diptera) in surface sediments of the sinkholes (cenotes) of the Yucatan Peninsula: Diversity and distribution
    (Vydavateľstvo PAGEPress, 2018) Hamerlík, Ladislav; Wojewódka, Marta; Zawisza, Edyta; Cohuo Duran, Sergio; Macario Gonzalez, Laura; Pérez, Liseth; Szeroczyńska, Krystyna
    Cenotes (sinkholes), formed by the dissolution of the carbonate rock, are the most common waterbodies on the Yucatan Peninsula. Despite their unique features and great amount in the region, our knowledge on the biota of cenotes remains fragmentary. Within the present study we analysed chironomid remains from surface sediment of ten cenotes situated in SE Mexico. In total, 20 taxa of 17 genera were recorded, and the total diversity was estimated to ~30 taxa. The most common taxa were Polypedilum (Tripodura) sp., Tanytarsus ortoni-type, Fittkauimyia sp., Labrundinia sp. and Endotribelos sp. There was a great variability in head capsule abundance among cenotes, ranging from 1 to 64 individuals per site with significantly higher number of remains recorded in open cenotes compared to the closed, cavern types. The results indicate that beside ecological features, such as low trophy, oxygen depletion, simplified habitat structure and fish predation, there are also taphonomical processes connected to the specific nature of cenotes that can hinder the accumulation of biological remains in the sediment. We conclude that due to poor sedimentation and preservation of remains, cenotes have limited potential for palaeolimnological studies.