Horst Lange-Bertalot

Frankophila, Mayamaea und Fistulifera: drei neue gattungen der klasse bacillariophyceae

Summary Distinct homogeneous clusters of established diatom taxa are described as three new genera. Only the nomenclatural type of the first genus, Frankophila similioides , is introduced as a new species. Two other species, F. loetschertii and F. maillardii belong to this genus with a unique complex of characteristic features of the Fragilariaceae, in particular of the subgenus Staurosira , and of naviculoid Raphideae. Actually 13 taxa of Navicula sensu lato belong to Mayamaea with M. atomus as type species whereas Navicula pelliculosa, Navicula saprophila and Navicula iranensis are transferred to Fistulifera . In addition to these proposals Stauroneis spicula is transferred from the actually used combination Navicula spicula to the genus Haslea Simonsen .

Diatoms in springs of the Alps: spring types, environmental determinants, and substratum

Abstract.  Spring habitats are highly diverse and have a mosaic microhabitat structure. They are endangered by diffuse exploitation as drinking-water resources, an impact likely to increase with climate change. Diatoms were sampled from stones and bryophytes in 110 nonthermal, near-natural springs in the southeastern Alps (Trentino) and 16 carbonate springs in the Dolomiti Bellunesi National Park. Fuzzy clustering identified 6 assemblages in the main types of springs. Carbonate rheocrenes hosted Achnanthidium spp., Gomphonema elegantissimum, and Nitzschia fonticola. Several of these species are rheophilic. This group was divided into 4 subassemblages defined by decreasing A. lineare and increasing A. pyrenaicum with increasing flow. Carbonate rheocrenes with shading or moderate NO3− enrichment contained a majority of sciaphilic and NO3-tolerant taxa: Cocconeis taxa, Amphora spp., Caloneis fontinalis, Reimeria spp., and Eunotia arcubus. Well-buffered siliceous rheocrenes supported Diatoma spp., Eunotia minor, Encyonema minutum, Navicula exilis, and Planothidium lanceolatum. Many of these species are heliophilic and rheophilic. Carbonate rheocrenes with lower conductivities or seasonal desiccation contained typical taxa of unstable environments: Diadesmis spp., Planothidium frequentissimum, Meridion circulare, and Achnanthidium dolomiticum. Carbonate rock-face seepages and some tufa springs supported xerotolerant diatom species with a preference for higher conductivities: Encyonopsis spp., Delicata spp., Gomphonema lateripunctatum, Denticula spp., and Cymbopleura spp. Siliceous seepages and pool springs, some very-low alkalinity rheocrenes, and 1 iron spring were characterized by acidophilous mire taxa, such as Eunotia spp., Frustulia crassinervia, and Tabellaria flocculosa, and very-low-alkalinity indicators, such as Psammothidium acidoclinatum. The other iron springs harbored species-poor assemblages with low numbers of cells. Many diatom species showed a significant preference for stones or bryophytes. Epibryon had higher richness and diversity than epilithon, and mean diversity did not differ among the most frequent bryophyte species. Bryophytes are quick and easy to sample and are proposed as the target substratum for diatom-based assessments of springs.

DIATOMS LIVING INSIDE THE THALLUS OF THE GREEN ALGAL LICHEN COENOGONIUM LINKII IN NEOTROPICAL LOWLAND RAIN FORESTS1

Coenogonium linkii Ehrenb. is a very common filamentous lichen, growing on stems, hanging roots, and lianas in the understory of neotropical lowland rain forests. We investigated several thalli of this species from locations in Panama and French Guiana. All thalli were inhabited by various species of terrestrial diatoms, which were found between the thallus filaments on extracellular material of the mycobiont. We identified 18 species of diatoms belonging to nine genera: Diadesmis, Eunotia, Hantzschia, Luticola, Melosira, Nitzschia, Orthoseira, Pinnularia, and Stauroneis. The potential benefits both diatoms and lichens could derive from symbiosis in relation to water, irradiance, and nitrogen availability are discussed.

DIATOM BIODIVERSITY OF SPRINGS IN THE BERCHTESGADEN NATIONAL PARK (NORTH-EASTERN ALPS, GERMANY), WITH THE ECOLOGICAL AND MORPHOLOGICAL CHARACTERIZATION OF TWO SPECIES NEW TO SCIENCE

Diatom assemblages were investigated in 9 springs of the Berchtesgaden National Park (carbonate substratum; north-eastern Alps, Germany), by collecting individual samples from the main substrata (stones, bryophytes, surface sediment), and measuring an extensive number of environmental variables. Overall, 104 taxa belonging to 39 genera were found. The highest number of taxa observed in any one sample was 37. The Shannon-Wiener Diversity Index varied between 1.2 and 2.4. The most frequent (counted in ≥ 4 samples) and abundant (maximum relative abundance > 5%) species were Achnanthidium minutissimum, Meridion circulare, Diatoma mesodon, Eucocconeis laevis, Navicula leistikowii, Denticula tenuis, Encyonema sublangebertalotii sp. nov., Planothidium lanceolatum, Achnanthidum pyrenaicum, Eunotia arcubus, Navicula cataracta-rheni, Rossithidium petersenii, Achnanthidum dolomiticum, Diploneis krammeri, Navicula cryptotenella, and Reimeria sinuata. The proportion of species belonging to one of the threat categories of the Red List for central Europe was 54%, and included species belonging to category 3 (“Endangered”): Eucocconeis flexella, Navicula moenofranconica, N. wildii, and Rossithidium petersenii. Two species new two science were discovered and described; one species was transferred to the genus Sellaphora (S. perhibita comb, nov.), and its ultrastructure was documented in detail. Encyonema sublangebertalotii sp. nov. resembles widely distributed species such as E. minutum and E. lange-bertalotii from which it can be distinguished by the outline (in particular the endings), dimensions, external raphe course and areolae density. Moreover, it appears to be mainly epiphytic in oligo(meso)trophic springs. Oligotrophic conditions might be important also for the second new species, Eunotia glacialispinosa sp. nov. which can be easily distinguished from similar species by its dimensions, striae and areolae density, distal raphe course, and by the presence of the characteristic spines. In Berchtesgaden it occurred exclusively in a specific spring type (seepages), and was found to develop also in comparable habitats (e.g. small dystrophic lake in a fen) by examining materials from several countries in the North of Europe. All these habitats had slightly alkaline or acidic pH but never presented ombrotrophic conditions. The comparison with a carbonate National Park located at the southern margin of the Alps (Dolomiti Bellunesi) revealed many similarities but also interesting differences mostly linked to the geographic distribution of specific spring types.

ACHNANTHIDIUM DOLOMITICUM SP. NOV. (BACILLARIOPHYTA) FROM OLIGOTROPHIC MOUNTAIN SPRINGS AND LAKES FED BY DOLOMITE AQUIFERS

A new benthic freshwater diatom, Achnanthidium dolomiticum sp. nov., was identified from light and scanning electron micrographs. The most characteristic morphological features are a narrow, but distinctive fascia; a filiform raphe with narrowly spaced central ends and a very narrow and straight axial area on the raphe valve; a convex‐shaped rapheless valve; the length/width ratio; and valve outline. The new species, has been found so far to be mainly epiphytic on bryophytes and aquatic vascular plants in carbonate springs and lakes of the Italian Alps. The environmental preferences of the new species, as assessed by the comparative analysis of these sites, appear to be quite distinctive. These freshwater habitats are fed by drainage basins dominated by dolomite lithology with medium mineralization, are oligotrophic, and are affected by seasonal desiccation.

The Diatom Species Fragilaria martyi (Heribaud) Lange-Bertalot, Identity and Ecology

Summary Subject of this study was Fragilaria martyi ( Heribaud ) Lange-Bertalot (syn. Opephora martyi Heribaud ) an opephoroid diatom species occurring in fresh- and slightly brackish-water environments. Recent and fossil samples collected from the Baltic Sea, Chile, France, Germany, Iceland and Poland were studied by means of light and electron microscopy. Due to the fact that Round in Round et al.: (1990) has taken this species as the typus generis of the new monotypic genus Martyana special attention has been paid to those features which have been evaluated as important for its independent generic position. It is shown that the criteria chosen by Round are insufficient for establishing the diatom genus Martyana. The diacritic features proposed by Round i.e. absence of linking spines and the occurrence of the “step” on the valve surface are found to occur facultatively. In addition an updated information concerning ecological requirements of F. martyi is given.

Four new species of Nitzschia sect. Tryblionella (Bacillariophyceae) resembling N. parvula

Abstract In the course of research on the diatoms from surface sediments sampled in the marine littoral and sublittoral worldwide, and in some freshwater localities in central Europe, several problematic taxa were encountered resembling Nitzschia parvula. We therefore undertook a light and scanning electron microscopical study of five species of Nitzschia belonging to the section Tryblionella. After a period of misidentification, one of the taxa studied, N. parvula, is now known from the type preparation. The remaining taxa are either new to science or have previously lacked formal descriptions. The first of them is found in freshwater habitats and is described here as N. beyeri Lange-Bertalot, whereas the second, from the tropical marine littoral, is described as N. schweikertii Witkowski, Lange-Bertalot, Ruppel & Kociolek. The third species is known in the literature by the manuscript name ‘Nitzschia subconstricta Grunow’. However, this name was not validly published and subconstricta has recently been used for another species, described by Desikachary & Prema (1987). Grunows species is validly described here as N. ligowskii Witkowski, Lange-Bertalot, Kociolek & Brzezinska. It inhabits the marine littoral and is characterized by a very wide geographical distribution. The fourth new taxon, described here as N. buschbeckii Witkowski, Lange-Bertalot & Ruppel is known so far only from the Antarctic.

Cymbella tridentina sp. nov. (Bacillariophyta), a crenophilous diatom from carbonate springs of the Alps

Abstract A new benthic freshwater diatom, Cymbella tridentina sp. nov., was identified with the aid of light and scanning electron micrographs. The most characteristic morphological features are the valve outline (in particular, the shape of the ventral margin), the number of stigmata, and the length/breadth ratio. The new species was epilithic in carbonate, mountain, flowing springs in 3 Natural Parks of the Alps. The environmental preferences of the new species, assessed by the comparative analysis of the sites where it was found and by seasonal and longitudinal-distribution data available for the type locality, are quite distinctive. The new species appears to be rheophilic and oligotraphentic (not present in N-enriched sites), characteristic of dolomite mountain ranges (even if dolomite is not the dominating carbonate rock in the basin), and to develop year-round with low relative abundances (peaks associated with high discharge in autumn and spring). The combination of these ecological requirements might determine the preferential occurrence of C. tridentina sp. nov. in close-to-pristine, carbonate, mountain, flowing springs. The preference of the new species for the spring zone of running waters, and its possible use as an integrity indicator, is discussed in the wider context of crenobiosis. The importance of oligotrophic headwaters for the integrity of running-water systems and for the conservation of freshwater biodiversity, is highlighted.

NEW AND INTERESTING NAVICULA TAXA FROM WESTERN AND NORTHERN EUROPE

Nine Navicula species observed in European rivers and lakes are discussed using light and scanning electron microscopy. Four of them are described as new species: Navicula antverpiensis Van de Vijver & Lange-Bertalot sp. nov., N. wendlingii Lange-Bertalot, Hofmann & Van de Vijver sp. nov., N. lacuum Lange-Bertalot, Hofmann, Werum & Van de Vijver sp. nov. and Navicula suecicarum Van de Vijver, Jarlman & Lange-Bertalot. The taxonomy of five other, already established, taxa is investigated: Navicula neomundana(Lange-Bertalot) Van de Vijver, Jarlman & Lange-Bertalot stat. nov., Navicula simulata Manguin syn. Navicula symmetrica Patrick, Navicula schroeteri Meister s. str. and N. escambia (Patrick) Metzeltin & Lange-Bertalot. The ecological preferences and distribution for each species are briefly discussed. Navicula veneta Kützing is formally lectotypified.

NUPELA EXOTICA SPECIES NOVA: UNE DIATOMÉE D'UN AQUARIUM TROPICAL D'EAU DOUCE. AVEC DES REMARQUES SUR LA BIOGÉOGRAPHIE DU GENRE / Nupela exotica sp. nov., a diatom from a tropical freshwater aquarium. With comments on the genus biogeography

A new naviculoid diatom species, Nupela exotica Monnier, Lange-Bertalot & Bertrand spec. nov., has been discovered in a tropical freshwater aquarium near Orléans (France). It is described on the basis of SEM studies, complemented by LM observations. The diatom flora and water characteristics are particular, since taxa from Europe and from tropical zones are associated. Among 54 counted taxa three belong to the recently established genus Nupela. The water of the aquarium is fairly acid, rich in nutrients and mineral content, the specific conductance is moderately high. Biogeography and ecology of N. exotica are discussed and compared with other species of the genus.