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Volume 58, Issue 4

2019 Next

Publication date: 23.12.2019

Description

Photo on the cover fromr: De Jager  G. P.,  Basson L., Van Marwijk J. (2019) A New Trichodina Species (Peritrichia: Mobilida) from Anuran Tadpole Hosts, Sclerophrys spp. in the Okavango Panhandle, Botswana, with Comments on this Taxon. Acta Protozool58: 141-153.

Licence: CC BY-NC-ND  licence icon

Editorial team

Editor-in-Chief Orcid Krzysztof Wiąckowski

Issue content

Won Je Lee

Acta Protozoologica, Volume 58, Issue 4, 2019, pp. 167 - 189

https://doi.org/10.4467/16890027AP.19.016.12018

A total of 155 species and 75 genera were found at marine sediments in Sydney region (Australia) and are described using light microscopy: 117 species at Port Botany, 111 species at Kogarah Bay, 94 species at Woolooware Bay, 126 species at Quibray Bay, 74 species at Avoca beach, 48 species at Watsons Bay. The records include accounts of 15 unidentified taxa and two new taxa: Eoramonas jungensis sp. nov. (Eoramonas gen. nov.), Protaspa flexibilis sp. nov. Most flagellates described here have been found at other locations worldwide, but many species not reported from any other locations. I am unable to assess if these species are endemic because of the lack of intensive studies elsewhere. However, these results suggest that the flagellate communities from Botany Bay are distinctive.

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Jingbao Li, Keqing Wen , Erkang Zhu , Jingyi Wang

Acta Protozoologica, Volume 58, Issue 4, 2019, pp. 191 - 200

https://doi.org/10.4467/16890027AP.19.017.12019

A soil urostylid ciliate Extraholosticha sylvatica, isolated from southern China, is studied using live observation and protargol impregnation. The main ontogenetic features of E. sylvatica are as follows: (a) in the proter, only the posterior part of the parental adoral zone of membranelles is renewed, while the anterior portion is retained; undulating membranes anlage undergo, like most hypotrichs, depolymerization of old undulating membranes and differentiation of new structures; (b) the oral primordium in the opisthe and the frontoventraltransverse cirral anlagen in both daughter cells are formed with contribution of the parental midventral cirri; (c) three frontal, one buccal, three to five frontoventral, one or two frontoterminal, two or three pretransverse ventral and six to 11 transverse cirri and 16–22 midventral pairs are generated from frontoventral-transverse cirral anlagen; (d) in both the left and the right marginal rows as well as the dorsal kineties, each two anlagen are formed intrakinetally; three to six caudal cirri are formed at the posterior end of the 5th dorsal kinety anlage; (e) the macronuclear nodules fuse into a single mass during the process.

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Najla Baković, Ferry J. Siemensma , Robert Baković, Josip Rubinić

Acta Protozoologica, Volume 58, Issue 4, 2019, pp. 201 - 215

https://doi.org/10.4467/16890027AP.19.018.12020

Karst freshwater caves are subterranean habitats characterized by the constant absence of light and relatively small variations of temperature and air humidity. They are mostly food deprived environments, with the exception if large bat colonies are present or if they are intensively supplied with organic matter by sinking rivers. Even though these habitats are often described as harsh, they have enabled the evolution of highly specialized and often endemic animals. The cave eukaryotic micro-organisms, on the other hand, are scarcely researched. The results of research of testate amoebae in the caves of the Dinaric arc detected 23 species, 12 of which were first found in caves. Also, a description of Centropyxis bipilata sp. nov. is presented. This species is clearly distinguished from other described species based on shell size, the presence of two struts and the usually dark ring around the aperture. Testate amoebae were registered on aquatic and terrestrial cave sediments and transitional habitats (like hygropetric and wet walls). The most frequent species within the samples were: Trinema lineare, Cryptodifflugia oviformis and Centropyxis bipilata sp. nov. Maximum diversity of testate amoebae was registered in Ponor Kovači with twenty species. In 24.4 % of the investigated samples  microphototrophs were found, implying good surface-subsurface connectivity that could also affect testate amoebae diversity. This research showed that caves are underestimated habitats that can provide us with new data about the testate amoebae biogeography and diversity.

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Giulia M. Ribeiro, Paulo Inácio Prado , Renato Mendes Coutinho , Marina Costa Rillo , Samuel Pereira Junior, Alfredo L. Porfírio-Sousa, Daniel J. G. Lahr

Acta Protozoologica, Volume 58, Issue 4, 2019, pp. 217 - 233

https://doi.org/10.4467/16890027AP.19.019.12021

Coexistence usually are exceeding the explicable rate by competitive exclusion principle. Since the pioneer Gause, many studies have used protist microcosm systems to study competitive exclusion. We explored a two-species system with the testate-amoebae: (Arcella intermedia and Pyxidicula operculata), where competitive exclusion is expected to occur. We determined their growth curves individually and under competitive interaction. We used a state-space model to represent system dynamics and calculated posterior population sizes simulating competition dynamics. Contrarily to our expectation, Arcella and Pyxidicula showed similar growth rates (1.37 and 1.46 days–1 respectively) and only different carrying capacity (1,997 and 25,108 cells cm–2 respectively). The maximum number of cells of both species when growing in competition was much lower if compared to the monospecific cultures (in average, 73% and 80% less for Arcella and Pyxidicula respectively). However, our competition experiments always resulted in coexistence. According to the models, the drop in growth rates and stochasticity mainly explains our coexistence results. We propose that a context of ephemeral resources can explain these results. Additionally, we propose generating factors of stochasticity as intraspecific variation, small population effects, toxicity of waste products and influence of the bacterial community.

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