Biogeography and phenotypic plasticity in silica-scaled chrysophytes (Synurophyceae)

CONLUSIONS Results of the Papers 1 and 2 summarizing Mallomonas distribution rather support the"moderate endemicity model" of Foissner. The most of Mallomonas species were cosmopolitan or widely distributed, but we also found several species with geographically restricted occurrence contradicting the "ubiquity model". Besides two Asian endemics there are three Mallomonas species (M. multiunca, M. oviformis, and M. punctifera var. punctifera) not conforming to ubiquity model due to their highly nonrandom distribution in subtropic to subarctic zones of the Northern Hemisphere. Several others examples of Mallomonas species with restricted distribution are given in literature. Mallomonas kalinae was isolated and described from a peaty pool in North Bohemia (Paper 3). This strain together with the Synura curtispina strain was used for investigation of scale and bristle plasticity under different temperatures (Paper 4). Changes in morphology of silicate structures in relation to temperature were significant, although the large part of variability was caused by different position on the cell. Bristles become significantly shorter with increasing temperature. An inverse relationship between size of scales and temperature corresponding to the temperature-size rule was found. The main scale characters were stable...Závěr Výsledky Článků 1 a 2 zabývající se rozšířením zástupců rodu Mallomonas spíše podporují Foissnerův umírněný model endemického rozšíření. Většina druhů rodu Mallomonas je sice kosmopolitně či široce rozšířena, avšak našli jsme i několik druhů s geograficky omezeným výskytem, které nepodporují ubikvitní model. Vedle dvou asijských endemitů jsou to tři druhy (M. multiunca, M. oviformis, and M. punctifera var. punctifera), které neodpovídají ubikvitnímu modelu díky jejich vysoce nenáhodnému rozšíření od subtropické do arktické zóny pouze severní polokoule. Několik dalších příkladů druhů Mallomonas s omezeným rozšířením lze najít v dalších publikacích. Mallomonas kalinae byl izolován a popsán z rašelinné tůně v severních Čechách (Článek 3). Tento kmen byl společně s jedním kmenem Synura curtispina použit pro studium plasticity šupina a ostnů za různé teploty (Článek 4). Změny v morfologii křemičitých struktur ve vztahu k teplotě byly signifikantní, ačkoliv velká část variability je způsobena rozdílnou pozicí šupin na buňce. Ostny se signifikantně zkracovaly se stoupající teplotou. Mezi velikostí šupin a teplotou byl nalezen inverzní vztah odpovídající teplotně-velikostnímu pravidlu. Hlavní znaky na šupinách se v jednotlivých teplotách neměnily. Kombinace morfologického a molekulárního přístupu k vyjasnění...Department of BotanyKatedra botanikyFaculty of SciencePřírodovědecká fakult

Biogeography and phenotypic plasticity in silica-scaled chrysophytes (Synurophyceae)

CONLUSIONS Results of the Papers 1 and 2 summarizing Mallomonas distribution rather support the"moderate endemicity model" of Foissner. The most of Mallomonas species were cosmopolitan or widely distributed, but we also found several species with geographically restricted occurrence contradicting the "ubiquity model". Besides two Asian endemics there are three Mallomonas species (M. multiunca, M. oviformis, and M. punctifera var. punctifera) not conforming to ubiquity model due to their highly nonrandom distribution in subtropic to subarctic zones of the Northern Hemisphere. Several others examples of Mallomonas species with restricted distribution are given in literature. Mallomonas kalinae was isolated and described from a peaty pool in North Bohemia (Paper 3). This strain together with the Synura curtispina strain was used for investigation of scale and bristle plasticity under different temperatures (Paper 4). Changes in morphology of silicate structures in relation to temperature were significant, although the large part of variability was caused by different position on the cell. Bristles become significantly shorter with increasing temperature. An inverse relationship between size of scales and temperature corresponding to the temperature-size rule was found. The main scale characters were stable..

Chrysosphaerella rotundata Skaloudova & Skaloud 2013, sp. nov.

Chrysosphaerella rotundata Škaloudová & Škaloud, sp. nov. (Figs. 1–6) Colonies spherical, consisting of cells bearing two flagella. Cells covered by numerous scales and spines. Three size classes of scales occur: large circular scales (3.0–3.5 × 2.2–3.1 µm), large oval scales (2.0–3.1 × 1.3–2.4 µm), and smaller oval scales (1.5–1.7 × 1.2 µm). Scales patterned with a series of short ridges forming a scalloped shaped pattern. Spines with a shaft joining the two plates of the bobbin-like structure. The length of the spines varies from 4 µm to 10 µm. Cysts unknown. Type:— FINLAND. Keski-Suomi, 62° 15' 1.07" N, 26° 34' 48.00" E, a small, oligotrophic unnamed lake, water temperature 5.6 °C, pH 7, conductivity 40 µS cm -1, coll. Škaloudová & Škaloud, 1 May 2012 (holotype: Strain S 89.C4, frozen material deposited at the Culture Collection of Algae of the Charles University in Prague, Department of Botany, Benátská 2, 12801 Prague 2, Czech Republic). Fig. 2 is an illustration of the holotype. Cells were grouped into spherical colonies. Individual cells were spherical to pyriform, about 12–13 Μm long and 11 Μm wide, bearing two flagella. Cells were covered by numerous scales and spines. Three size classes of scales might be discerned; however, a continuous transition in size of scales existed. The majority of the scales were larger and oval in outline (Figs. 1, 3). The second type of the scales, larger and circular in outline, were produced less frequently (Fig. 2). However, presence of the large, circular-shaped scales was a main distinguishing character of Chrysosphaerella rotundata. Both large circular and oval scales were patterned with a series of short ridges forming a scalloped shaped pattern. The pattern of smaller oval scales (Fig. 3) was the same as that of larger scales, but often less distinct. The spines had a thick shaft joining the two plates of the bobbin-like structure (Figs. 4–5); however, a variation in the thickness of the shaft was observed and spines with a thinner shaft were found as well (Fig. 6). Etymology:— The specific epithet 'rotundata' refers to the rounded shape of scales. Phylogenetic analyses, ITS2 secondary structures:— Bayesian inference, Maximum Likelihood, and Maximum Parsimony analyses inferred from the concatenated SSU rDNA and rbc L sequences resulted in highly similar phylogenetic trees, recognizing the six main lineages within Chrysophyceae (Fig. 7). According to their members, the lineages could be recognized as traditionally defined orders: Chromulinales, Chrysosaccales, Hibberdiales, Hydrurales, Ochromonadales, and Synurales. With the exception of the Ochromonadales, all lineages were also significantly supported by ML and wMP analyses. Both analyses resolved the Ochromonadales as monophyletic, but without any statistical support. The genus Chrysosphaerella formed a firmly supported monophyletic lineage within the Chromulinales (Fig. 7). It was divided into two supported subclades. Chrysosphaerella rotundata was inferred as closely related to morphologically similar C. brevispina, with which it formed the first inferred subclade. The species differed by eight and eleven nucleotide substitution changes in the SSU rDNA and rbc L sequences, respectively. The second subclade consisted of C. longispina and two environmental Chrysosphaerella isolates. Since the isolates were molecularly characterized by only the SSU rDNA (summer isolate) or rbc L (winter isolate) sequence, we could not exclude that they in fact belong to the same genotype. The environmental isolates differed by two nucleotide substitution changes in the SSU rDNA and rbc L sequences from the C. longispina sequences. To further evaluate the degree of genetic differentiation of the closely related C. rotundata and C. brevispina, we additionally sequenced the ITS1- 5.8S rDNA-ITS2 region. The ITS1 region was hardly alignable, and the sequences differed significantly in their length (342 bp in C. rotundata vs. 294 bp in C. brevispina). Within the aligned regions, the divergence between the ITS1 rDNA sequences was approximately 15.5%. The length of the ITS2 region was similar in both species (293 bp in C. rotundata vs. 287 bp in C. brevispina), and the overall divergence between the ITS2 rDNA sequences was approximately 12.5%. In addition, we mapped the differences in the ITS2 sequence on a predicted ITS2 secondary structure (Fig. 8). Most of the differences were located in terminal and internal hairpin loops. Four compensatory base changes (CBCs) were found in the stem regions of helices I and II.Published as part of Škaloudová, Magda & Škaloud, Pavel, 2013, A new species of Chrysosphaerella (Chrysophyceae: Chromulinales), Chrysosphaerella rotundata sp. nov., from Finland, pp. 34-42 in Phytotaxa 130 (1) on page 37, DOI: 10.11646/phytotaxa.130.1.4, http://zenodo.org/record/508577

Morphological delineation and distribution patterns of four newly described species within the <i>Synura petersenii</i> species complex (Chrysophyceae, Stramenopiles)

<div><p>The <i>Synura petersenii</i> species complex represents a common, cosmopolitan and highly diverse taxon of autotrophic freshwater flagellates. In this paper, we describe and characterize four new species (<i>S. borealis</i>, <i>S. heteropora</i>, <i>S. hibernica</i> and <i>S. laticarina</i>) that have been identified during our extensive sampling of freshwater habitats in 15 European countries. Morphometric analyses of siliceous scales led to the significant phenotypic differentiation of all four newly described species, and their separation from other related species of the <i>S. petersenii</i> complex. Two of these newly described species (<i>S. hibernica</i> and <i>S. borealis</i>) can be clearly distinguished by characteristic large colonies consisting of elongated, lanceolate-shaped cells. Development of strongly elongated, narrow cells in <i>S. hibernica</i> could be explained by the adaptation of this species to oligotrophic conditions. Though morphologically distinct, <i>S. borealis</i> possesses an exceptionally high degree of genetic diversity, possibly indicating recent speciation and evolutionary diversification within this taxon. Three of the four newly described species exhibit restricted biogeographic distribution. The evolutionarily related <i>S. borealis</i> and <i>S. laticarina</i> occur only in Northern Europe, and seem to be adapted to colder areas. The most remarkable distribution pattern was observed for <i>S. hibernica</i>, which has a geographic distribution that is restricted to western Ireland.</p></div