Cell-division pattern and phylogenetic analyses of a new ciliate genus Parasincirra n. g. (Protista, Ciliophora, Hypotrichia), with a report of a new soil species, P. sinica n. sp. from northwest China

Abstract

Background Ciliated protists, a huge assemblage of unicellular eukaryotes, are extremely diverse and play important ecological roles in most habitats where there is sufficient moisture for their survivals. Even though there is a growing recognition that these organisms are associated with many ecological or environmental processes, their biodiversity is poorly understood and many biotopes (e.g. soils in desert areas of Asia) remain largely unknown. Here we document an undescribed form found in sludge soil in a halt-desert inland of China. Investigations of its morphology, morphogenesis and molecular phylogeny indicate that it represents a new genus and new species, Parasincirra sinica n. g., n. sp. Results The new, monotypic genus Parasincirra n. g. is defined by having three frontal cirri, an amphisiellid median cirral row about the same length as the adoral zone, one short frontoventral cirral row, cirrus III/2 and transverse cirri present, buccal and caudal cirri absent, one right and one left marginal row and three dorsal kineties. The main morphogenetic features of the new taxon are: (1) frontoventral-transverse cirral anlagen II to VI are formed in a primary mode; (2) the amphisiellid median cirral row is formed by anlagen V and VI, while the frontoventral row is generated from anlage IV; (3) cirral streaks IV to VI generate one transverse cirrus each; (4) frontoventral-transverse cirral anlage II generates one or two cirri, although the posterior one (when formed) will be absorbed in late stages, that is, no buccal cirrus is formed; (5) the posterior part of the parental adoral zone of membranelles is renewed; (6) dorsal morphogenesis follows a typical Gonostomum-pattern; and (7) the macronuclear nodules fuse to form a single mass. The investigation of its molecular phylogeny inferred from Bayesian inference and Maximum likelihood analyses based on small subunit ribosomal DNA (SSU rDNA) sequence data, failed to reveal its exact systematic position, although species of related genera are generally assigned to the family Amphisiellidae Jankowski, 1979. Morphological and morphogenetic differences between the new taxon and Uroleptoides Wenzel, 1953, Parabistichella Jiang et al., 2013, and other amphisiellids clearly support the validity of Parasincirra as a new genus. The monophyly of the family Amphisiellidae is rejected by the AU test in this study. Conclusions The critical character of the family Amphisiellidae, i.e., the amphisiellid median cirral row, might result from convergent evolution in different taxa. Amphisiellidae are not monophyletic.

Redescription, Morphogenesis, and Molecular Phylogeny of Pseudosincirra longicirrata nov. comb., With Establishment of a New Genus Pseudosincirra nov. gen. (Ciliophora, Hypotrichia)

“…Furthermore, we suggest that the possession of fine cirri and the relatively widely spaced cirri within all rows should be considered as plesiomorphies of this family/group and added in the diagnosis of the family. Some species of the family Deviatidae cluster with Strongylidium-Hemiamphisiella-Pseudouroleptus, which is close to Dorsomarginalia and Dorsomarginalian species in present and previous studies (Lu et al, 2020;Wang et al, 2020;Ma et al, 2021;Vd'ačný and Foissner, 2021). Hence, we disagree with Foissner (2016) that Deviatidae is possibly sister to the non-dorsomarginalian Kahliellidae Tuffrau, 1979, but closely related to Dorsomarginalia or Strongylidium-Hemiamphisiella-Pseudouroleptus.…”

“…Some species of the family Deviatidae cluster with Strongylidium – Hemiamphisiella – Pseudouroleptus , which is close to Dorsomarginalia and Dorsomarginalian species in present and previous studies ( Lu et al, 2020 ; Wang et al, 2020 ; Ma et al, 2021 ; Vd’ačný and Foissner, 2021 ). Hence, we disagree with Foissner (2016) that Deviatidae is possibly sister to the non-dorsomarginalian Kahliellidae Tuffrau, 1979, but closely related to Dorsomarginalia or Strongylidium – Hemiamphisiella – Pseudouroleptus.…”

Evaluation of the impact of wastewater irrigation on the soil's dielectric parameters

“…The soil samples were collected using “cell division method” (Ma et al, 2021; Wollenhaupt & Wolkowski, 1994). The sampling process involved marking a rectangular cell of size 25 × 40 m on the ground, from which samples were collected from 16 sites diagonally within the cell.…”

Multi-Gene Phylogeny of the Ciliate Genus Trachelostyla (Ciliophora, Hypotrichia), With Integrative Description of Two Species, Trachelostyla multinucleata Spec. nov. and T. pediculiformis (Cohn, 1866)

“…Hypotrichs (subclass Hypotrichia Stein, 1859) are not only one of the most morphologically differentiated ciliate groups, but also one of the most confused in terms of systematics and phylogeny (for reviews, see Berger, 1999 , 2006 , 2008 , 2011 ; Chen L. et al, 2020 , 2021 ; Paiva, 2020 ; Song et al, 2020 ; Xu W. et al, 2020 ; Xu Y. et al, 2020 ; Wang et al, 2020 ; Zhang et al, 2020a ; Jung et al, 2021 ; Li et al, 2021a , b ; Luo et al, 2021 ; Vd’ačný and Foissner, 2021 ). In the past decades, identification of hypotrichs mostly relied on interphase morphology, ontogenetic processes, and gene encoding for the small subunit (18S) rRNA molecule ( Foissner, 2016 ; Song and Shao, 2017 ; Jung and Berger, 2019 ; Kaur et al, 2019 ; Kim and Min, 2019 ; Ma et al, 2021 ; Wang et al, 2021a ). Recently, multigene analyses, including 18S rDNA, internal transcribed spacer (ITS) region (comprising ITS1, 5.8S, and ITS2), and large subunit (28S) rDNA provided more robust interpretations of phylogenetic relationships among hypotrichs than those based on a single gene ( Dong et al, 2020 ; Lu et al, 2020 ).…”