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Four small-celled Planothidium species from Central Europe proposed as new to science

Bąk M., Lange-Bertalot H.

Oceanological and Hydrobiological Studies

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2014

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Vol. 43, No. 4

346--359

EN

Four small-celled taxa are presented and described — Planothidium werumianum, P. pumilum, P. rhombiculum and P. rostratoholarcticum. Planothidium werumianum, P. pumilum and P. rhombiculum are proposed as new to science and P. rostratoholarcticum as a new name for Achnanthes lanceolata var. rostrata Hustedt 1911. The latter, coming from Germany, is transferred to Planothidium in the species rank. The new name — P. rostratoholarcticum — is necessary to avoid a junior homonym, i.e., Planothidium rostratum (Østrup) Lange-Bertalot 1999, a species described from tropical Thailand. The new taxa were compared to several other, more or less similar small-celled Planothidium spp., such as P. rostratum (Østrup) Lange-Bertalot, P. minutissimum (Krasske) Lange-Bertalot, P. granum (Hohn & Hellerman) Lange-Bertalot, P. daui (Foged) Lange-Bertalot, P. frequentissimum (Lange-Bertalot) Lange-Bertalot and P. engelbrechtii (Cholnoky) Round & Bukhtiyarova. Significant differences could be found through light- and electron microscopic fine structure analysis. Planothidium pumilum and P. rostratoholarcticum occur mainly in eutrophic alkaline rivers and lakes with medium to high conductivity, likewise in estuaries, lagoons, and backwater of the North Sea and the Baltic Sea. Planothidium werumianum and P. rhombiculum were found in small carbonate-rich rivers originating from medium altitude mountains.

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Diatoma polonica sp. nov. : a new diatom (Bacillariophyceae) species from rivers and streams of southern Poland

Bąk M., Lange-Bertalot H., Nosek J., Jakubowska Z., Kiełbasa M.

Oceanological and Hydrobiological Studies

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2014

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Vol. 43, No. 2

114--122

EN

Diatoma polonica, a species first observed in samples from the Western Carpathians river systems in southern Poland, is described as a species new to science. The new species status resulted from the fact that the dimensions of cells found did not fit any of the diagnoses given in the literature for the European Diatoma taxa established so far. The genus is rather species-poor, even when the entire Holarctic flora is taken into account. The new species is morphologically closest to Diatoma moniliformis Kützing, particularly with respect to the vague resemblance of the valve outlines and the presence of a rimportula in each valve pole. Further, more or less similar taxa are D. tenuis Agardh, D. problematica Lange-Bertalot and D. mesodon (Ehrenberg) Kützing, all distinguished, in addition to other specific characteristics, by the rimoportulae regularly present at only one valve pole. Characteristics of D. polonica are described and compared with those of other species based on light and scanning electron microscopy.

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A first ecological evaluation of the diatom flora in Central Europe: species diversity, selective human interactions and the need for habitat protection

Lange-Bertalot H.

Oceanological Studies

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1998

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Vol. 27, No. 2

5-12

EN

The recently revised check-list of diatoms found in Germany contains 1437 taxa (1632 taxa have been recorded for Central Europe). Clear correlations with ecological conditions were established for 1000 taxa (70% of 1437). 267 predominantly marine taxa also occur in inland waters; they penetrate progressively into rivers contaminated with industrial waste waters. 61 taxa are aerophilic and 164 eutraphentic, 91 tolerant to all trophic conditions. Very few species in these ecological groupings are endangered. However, at last 417 oligo- or slightly mesotraphentic taxa are included in the "Red List". This strongly indicates that conserving oligo- and dystrophic waters as well as lower mesotrophic habitats can best protect species diversity.