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Zidarova R.,Central Laboratory of General Ecology | van de Vijver B.,National Botanic Garden of Belgium | Quesada A.,Autonomous University of Madrid | de Haan M.,National Botanic Garden of Belgium
Plant Ecology and Evolution | Year: 2010

Background and aims - The non-marine diatom fora of Livingston Island (South Shetland Islands, Maritime Antarctic Region) is currently under revision. One of the genera that still needed a revision is the genus Hantzschia, quite common in terrestrial habitats of the Antarctic Region. Methods - Using both Light Microscopical and Scanning Electron Microscopical techniques, the morphology of all Hantzschia taxa, present in the samples from Livingston Island, has been analysed. Each taxon is compared with all other possible similar Hantzschia taxa, known worldwide. Key results - Apart from the already known Hantzschia abundans and H. amphioxys f. muelleri, fve new Hantzschia species are described: Hantzschia acuticapitata Zidarova & Van de Vijver sp. nov., H. confuse Van de Vijver & Zidarova sp. nov., H. hyperaustralis Van de Vijver & Zidarova sp. nov., H. constricta Van de Vijver & Zidarova sp. nov. and H. incognita Zidarova & Van de Vijver sp. nov. Conclusions - The obtained results confrm the presence of a typical and highly specifc non-marine diatom fora in the Antarctic Region and contradict the generally accepted idea about the cosmopolitanism of diatoms.


Zidarova R.,Sofia University | Kopalova K.,Charles University | Van de Vijver B.,National Botanic Garden of Belgium
Phytotaxa | Year: 2012

During the ongoing revision of the non-marine diatom flora of Livingston Island (South Shetland Islands, Maritime Antarctic Region) the taxonomy and morphology of all Pinnularia taxa, excluding the section Distantes, present in the samples from Livingston Island, have been analysed. Seventeen different Pinnularia taxa have been recorded. Apart from those previously described from the Antarctic Region (P. subcapitata var. elongata, P. gemella, P. austroshetlandica) and the Andes (P. strictissima), thirteen unknown taxa have been found. Based on their unique morphological features, twelve are described as new in this paper: P. australodivergens sp. nov., P. australoglobiceps sp. nov., P. australomicrostauron sp. nov., P. australoschoenfelderi sp. nov., P. hamiltonii sp. nov., P. livingstonensis sp. nov., P. magnifica sp. nov., P. microstauroides sp. nov., P. pseudolaucensis sp. nov., P. sergiplaiana sp. nov., P. subcarteri sp. nov. and P. subaltiplanensis sp. nov. For one, only a few specimens have been found and at present they cannot be identified with 100% certainty. © 2012 Magnolia Press.


Peeters K.,Ghent University | Ertz D.,National Botanic Garden of Belgium | Willems A.,Ghent University
Systematic and Applied Microbiology | Year: 2011

We studied the culturable heterotrophic bacterial diversity present at the site of the new Princess Elisabeth Station at Utsteinen (Dronning Maud Land, East Antarctica) before construction. About 800 isolates were picked from two terrestrial microbial mat samples after incubation on several growth media at different temperatures. They were grouped using rep-PCR fingerprinting and partial 16S rRNA gene sequencing. Phylogenetic analysis of the complete 16S rRNA gene sequences of 93 representatives showed that the isolates belonged to five major phyla: Actinobacteria, Bacteroidetes, Proteobacteria, Firmicutes and Deinococcus-Thermus. Isolates related to the genus Arthrobacter were the most prevalent whereas the genera Hymenobacter, Deinococcus, Cryobacterium and Sphingomonas were also recovered in high numbers in both samples. A total of 35 different genera were found, the majority of which has previously been reported from Antarctica. For the genera Aeromicrobium, Aurantimonas, Rothia, Subtercola, Tessaracoccus and Xylophilus, this is the first report in Antarctica. In addition, numerous potential new species and new genera were recovered; many of them currently restricted to Antarctica, particularly in the phyla Bacteroidetes and Deinococcus-Thermus. © 2011 Elsevier GmbH.


Ertz D.,National Botanic Garden of Belgium | Tehler A.,Enheten for Kryptogambotanik
Fungal Diversity | Year: 2011

A two-locus phylogenetic study of the order Arthoniales is presented here using the nuclear ribosomal large subunit (nucLSU) and the second largest subunit of RNA polymerase II (RPB2). This analysis is the first large phylogeny of this fungal group and includes 476 sequences and 240 specimens representing 132 species sampled from 31 genera (in their traditional circumscription). In addition to the previously recognized families (Arthoniaceae, Chrysothricaceae and Roccellaceae), three additional family-level groups are recovered, one being poorly supported. Therefore, the new family Roccellographaceae is described and the family Opegraphaceae is reinstated. Morphological characters such as growth form, fruit body type, exciple, hypothecium and ascospores colour, ascospores septation pattern, and chemistry are found to be of limited use in delimiting families and genera, which indicates an unusual level of plasticity in the Arthoniales. This high level of homoplasy might indicate that the Arthoniales is an old group with taxa having evolved in parallel for very long times. The genera Arthonia, Arthothelium, Chiodecton, Hubbsia, Ingaderia, Lecanactis, Lecanographa, Llimonaea, Opegrapha, Roccellina, Schismatomma and Sclerophyton were found paraphyletic. In order to make these genera monophyletic, the new genera Dimidiographa, Fulvophyton, Paraingaderia, Paralecanographa, Paraschismatomma and Sparria are newly described and the genera Alyxoria, Dictyographa and Zwackhia reinstated. The new species Lecanactis borbonica and Paraingaderia placodioidea are described. © 2011 Kevin D. Hyde.


Verloove F.,National Botanic Garden of Belgium
Webbia | Year: 2010

Eleocharis pellucida J. Presl & C. Presl (Cyperaceae), native in south-eastern and eastern Asia, is reported for the first time as a xenophyte in Europe. It is locally abundant and well-naturalised in several heaths (baraggias) in the provinces of Biella, Torino and Vercelli (Piemonte, Italy) and possibly overlooked elsewhere. Diagnostic features are discussed and compared with those of related native and non-native species. An updated identification key for the genus Eleocharis in Piemonte as well as a photograph and an original line drawing are presented. Finally, the species' potential introduction history in Piemonte is discussed.


Van De Vijver B.,National Botanic Garden of Belgium
Phytotaxa | Year: 2012

A new centric diatom, Aulacoseira principissa sp. nov., is described from the sub-Antarctic region. The morphology of the species is illustrated using detailed light and scanning electron microscopy observations. Its main discriminating features include the presence of typical bifurcating spines, a single rimoportula, a typical valve heterovalvy with spineless separation valves and a variable striation pattern on the discus. The new species is compared to related species belonging to the complex of Aulacoseira distans. Aulacoseira principissa has a broad geographical distribution ranging from the sub-Antarctic islands in the southern Indian Ocean to South Georgia in the southern Atlantic Ocean. It is commonly found in slightly acidic, oligotrophic pools with low specific conductance values. © 2012 Magnolia Press.


De Block P.,National Botanic Garden of Belgium
Phytotaxa | Year: 2014

Two new Ixora species from Madagascar are described, Ixora lagenifructa and I. quadrilocularis. Ixora littoralis, previously positioned in the monospecific genus Thouarsiora, is newly named I. homolleae. These three species are characterized by 4-locular ovaries and fruits, 4-lobed stigmas, large fruits with thick walls and well-developed calyces. A fourth species, I. trimera, shows the same characters but its ovaries are 2-, 3- or 4-locular and its stigmas are 2-, 3- or 4- lobed. A dichotomous key, detailed descriptions and distribution maps are given for these four species, the only multilocular ones in Madagascar. © 2014 Magnolia Press.


Mayer C.,Catholic University of Leuven | Van Rossum F.,National Botanic Garden of Belgium | Jacquemart A.-L.,Catholic University of Leuven
Basic and Applied Ecology | Year: 2012

For insect-pollinated plant species, reproductive success and genetic exchange via the transfer of pollen between flowers depends (i.a.) on the efficiency, abundance and behaviour of floral visitors. These in turn are expected to respond to plant population size and flower density. High floral densities for example usually attract large numbers of pollinators that visit more flowers per plant or patch, which increases pollen deposition at short distances. Thus, population characteristics might serve as indicators for pollen dispersal patterns and help to identify suitable habitat size and quality for conservation measures. To test this hypothesis, we observed floral visitors of a generalist, entomophilous species, Comarum palustre, and compared their abundance and visitation rates in populations of different sizes and flower densities. At the same time, we mimicked pollen flow using fluorescent dye. In the large and dense populations, pollinator abundance and visitation rates were high and dye was dispersed to the edges of the populations (up to 200. m). In the medium-sized population with high flower density, insect abundance and visitation rates were unexpectedly low and dye dispersal declined very quickly. On the contrary, in the smallest population with scattered flowers, especially bumble bee abundance was similar to the large populations and dye dispersal mirrored this high bumble bee activity. Thus, our results indicate that in smaller habitat fragments, the mere size of a population might be insufficient to suggest pollen flow for a plant species. Instead, the abundance of its major pollinators should be considered. © 2012 Gesellschaft für Ökologie.


De Kesel A.,National Botanic Garden of Belgium | Haelewaters D.,Harvard University
Mycologia | Year: 2014

Laboulbenia littoralis is described from the halobiont Cafius xantholoma (Coleoptera, Staphylinidae); it previously was misidentified and not properly documented. Morphologically the new species belongs to a group of carabidicolous taxa similar to Laboulbenia pedicellata and especially Laboulbenia slackensis. It is generally accepted that the specificity of Laboulbeniales is based on their need for substances from the host. In this relatively strict context, shifts between unrelated hosts are difficult to explain. We present morphological and ecological evidence supporting the hypothesis that these fungi are capable of shifting between unrelated hosts as long as they share the same habitat. Adaptation to a particular environment, combined with a reduced dependence from specific nutrients of the host, explains the proposed interfamilial host shift. © 2014 by The Mycological Society of America.


Verloove F.,National Botanic Garden of Belgium
Willdenowia | Year: 2012

Recent molecular phylogenetic studies strongly recommend the amalgamation of the grass genera Cenchrus and Pennisetum. The generic name Cenchrus having priority, the species of Pennisetum need to be transferred to it. The correct names in Cenchrus for the 15 Pennisetum species in Europe and the Mediterranean area are provided, including four new combinations. © 2012 BGBM Berlin-Dahlem.

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