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Acta Protozoologica

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Volume 55, Issue 1

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Publication date: 17.02.2016

Licence: None

Editorial team

Editor-in-Chief Orcid Krzysztof Wiąckowski

Issue content

Klaus Hausmann, Gerd Günther, Diana Lehmann, Renate Radek

Acta Protozoologica, Volume 55, Issue 1, 2016, pp. 1-5

https://doi.org/10.4467/16890027AP.16.001.4042
The astomatous metaradiophryids are ciliates which live endosymbiotically in earthworms (Annelida, Lumbricidae). Their prominent hook apparatus is demonstrated in detail in light micrographs of living organisms as well as in scanning electron micrographs of Parducz-fixed cells. Since it was first observed, this structure has been interpreted as a ‘holdfast’ organelle preventing ciliates from being expelled prematurely from the intestine of the worm along with its excrements. No active movement of the hook has been reported in earlier papers or in our recent studies. Nevertheless, a detailed description of different parts of the hook apparatus exists in older literature, including a hypothesis on how these elements interact with each other to function as a holdfast device – without any experimental evidence. The suspected mode of function of this structure is questioned and critically discussed.
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Oriol Canals, Humbert Salvadó

Acta Protozoologica, Volume 55, Issue 1, 2016, pp. 7-18

https://doi.org/10.4467/16890027AP.16.002.4043

A new peritrich species highly tolerant to ammonium and nitrite, Epistylis camprubii n. sp., was found adhered to the biofilm of two advanced wastewater treatment plants treating high ammonium-loaded wastewater in Rubí, Spain. Its morphology, oral infraciliature and phylogenetic position in the peritrich clade were studied. The new species is a vase-shaped peritrich, constricted below the peristomial lip, with an in vivo average length of 58.7 ± 10.1 µm, average width of 32.0 ± 5.4 µm, and a longitudinally striated, compact stalk that occasionally exhibits uneven thickness and rarely shows transverse segments. The peristomial disc is commonly rounded or pointed, and rarely umbilicated. The C-shaped macronucleus is located in the adoral half of the body, and the only contractile vacuole lies in the adoral third of the zooid. The molecular analysis of the 18s gene sequence clustered E. camprubii n. sp. together with the other Epistylis, with the exception of Epistylis galea. 

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O. Roger Anderson

Acta Protozoologica, Volume 55, Issue 1, 2016, pp. 19-25

https://doi.org/10.4467/16890027AP.16.003.4044
Experimental evidence is presented to support a hypothesis that terrestrial naked amoebae, collected during late autumn from cold, moist temperate soil, develop a non-encysted, freeze-thaw resistant stage that is capable of surviving winter frozen soil. Therefore, in addition to cyst formation, naked amoebae may survive harsh, frozen winter soil in a dormant or resting stage that is capable of rapid resumed growth in spring, thus gaining an immediate competitive advantage in exploiting food and other environmental resources early after the winter thaw.
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Helge Abildhauge Thomsen, Jorun Karin Egge

Acta Protozoologica, Volume 55, Issue 1, 2016, pp. 27-32

https://doi.org/10.4467/16890027AP.16.004.4045
In an attempt to establish a taxonomy for the polar contingent of lightly calcified coccolithophores, we are currently dealing with species of Papposphaera. Here we describe a new species,Papposphaera heldalii sp. nov., based on material from Svalbard. The species is unique in terms of calyx design, which is an elegant modification of the standard P. sagittifera theme, and also in terms of the absence of central area calcification in body coccoliths. The species thus occupies a further step in a sequence of five Arctic forms ranging from P. sagittifera via P. sarion, P. arctica and P. iugifera to P. heldalii showing a gradual reduction of central area calcification in body coccoliths. P. heldalii is unique also in the sense that the species has not been found during any of the major Arctic TEM nanoplankton surveys conducted during the last decades. 
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Helge Abildhauge Thomsen, Jette Buch Østergaard, Mikal Heldal

Acta Protozoologica, Volume 55, Issue 1, 2016, pp. 33-50

https://doi.org/10.4467/16890027AP.16.005.4046
The re-examination of the lightly calcified Arctic coccolithophore species, Papposphaera sagittifera, has some inherent challenges due to the research history on this taxon. It is thus obvious in retrospect that the species description based on just a single specimen does not adequately account for the true identity of this taxon. Today we are aware of the existence of at least three species ofPapposphaera that have basically the same calyx design while being differentiated based on patterns of central area calcification. In order to remedy this we emend here the description of P. sagittifera and provide an epitype for the species. When realizing that species pairs ofPapposphaera and Turrisphaera share a life history, the new combination, P. borealis, was established to accommodate P. sagittifera and T. borealis. However, it turns out that ‘sagittifera’ is in fact the senior epithet by a few months, which means that the correct name for the species is P. sagittifera with T. borealis added as a synonym. While the P. sagittifera HET and HOL morphological variability across Arctic sites clearly leaves the impression of a single, fairly well defined species, the situation is different with respect to the occurrence of P. sagittifera in Antarctic waters. While there are obvious similarities between P. sagittifera HET across the Polar Regions there are also subtle differences, and most importantly it has been found that the Antarctic P. sagittifera shares a life history with a species of Turrisphaera that is markedly different from T. borealis. While awaiting molecular evidence the Antarctic material is tentatively referred to as P. sagittifera cfr.
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Yuri A. Mazei, Olga Belyakova, Olimpia Coppellotti, Richard J. Payne

Acta Protozoologica, Volume 55, Issue 1, 2016, pp. 51-59

https://doi.org/10.4467/16890027AP.16.006.4047
The testate amoebae (TA) of many potential habitats around the world have been barely investigated but data on species presence and abundance is essential to answering big questions about microbial biogeography and the diversity of protist life. One such habitat lacking basic data is epilithic mosses and lichens with only a small number of samples analysed in previous studies and no systematic attempt to understand potential environmental controls. We use a large dataset (n = 81) from sites in Russia, Switzerland and Italy to demonstrate that testate amoebae in this habitat are both abundant and diverse. The community of our samples was dominated by ubiquitous taxa and differed between the northern (Russia) and southern (Switzerland and Italy) sites, perhaps due to differences in climate or air quality. Community composition, concentration and diversity were explained by moisture content but not by elevation above the ground surface and there were no significant differences between communities of mosses and lichens. Surprisingly our data showed a significant difference between communities of epiphytic and epilithic lichens in the same region sampled at the same time. Our study adds to the evidence that moisture availability is a critical factor in structuring testate amoeba communities across habitats and highlights the paucity of knowledge of TA in many environments.
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