Life Cycle, Morphology, Ontogenesis, and Phylogeny of Bromeliothrix metopoides nov. gen., nov. spec., a Peculiar Ciliate (Protista, Colpodea) from Tank Bromeliads (Bromeliaceae)

Bromeliothrix metopoides was discovered in tank bromeliads from Central and South America. Pure cultures could be established in various media stimulating growth of its food, i.e. bacteria and heterotrophic flagellates of the genus Polytomella. The new ciliate was investigated in the light- and scanning electron microscope, with various silver impregnation techniques, and with molecular methods, using the small-subunit rDNA. The morphology and its changes during the life cycle are documented by 167 figures and a detailed morphometry. Bromeliothrix metopoides is about 27–55 × 22–36 μm in size and has a complex life cycle with Metopus-shaped, bacteriophagous theronts and trophonts (microstomes) and obovate, flagellate-feeding macrostomes having a large, triangular oral apparatus. The thin-walled resting cysts of the theronts and trophonts are uniquely ellipsoidal, while the thick-walled cyst of the macrostome morph is globular. Reproduction occurs in freely motile condition either by binary fission or polytomy, producing a unique, motile “division chain” composed of four globular offspring, of which the central ones are connected by a curious, plug-like holdfast. Division is associated with a complete reorganization of the parental oral and somatic infraciliature. Stomatogenesis is merotelokinetal as in other members of the order Colpodida. The right polykinetid is generated by the rightmost postoral kinety, while the left polykinetid is produced by the two left postoral kineties and five left side kineties. The division in freely motile condition resembles the Exocolpodidae Foissner et al., 2002, to which Bromeliothrix is tentatively assigned, differing from Exocolpoda mainly by the formation of a macrostome morph and a division chain. Bromeliothrix has a ciliary and silverline pattern typical for members of the family Colpodidae. This matches the molecular classification which, however, hardly reflects the outstanding division and life cycle, suggesting some decoupling of morphological and molecular evolution. The specific morphological and ontogenetic traits of Bromeliothrix are interpreted as adaptations to the highly competitive habitat, favouring r-selected life strategies. Bromeliothrix metopoides is widespread in various tank bromeliads and can be easily cultivated in a wide variety of limnetic and terrestrial media. Thus, it remains obscure why this ciliate is restricted to tank bromeliads, i.e. did not occur in about 2,000 soil and freshwater samples investigated globally, including some 100 samples from Central and South America

Cultellothrix velhoi gen. n., sp. n., a new Spathidiid Ciliate (Ciliophora: Haptorida) from a Brazilian Floodplain Soil

Summary. Cultellothrix velhoi sp. n. was discovered in floodplain soil from the Paraná River near the town of Maringá, Brazil, South America. Its morphology was investigated using live observation and protargol impregnation. Cultellothrix belongs to the gymnostomatous ciliate family Spathidiidae, where it represents a new genus characterized by the lateral location of the dorsal brush. Cultellothrix velhoi sp. n. differs from the European congener, C. lionotiformi

Four New Fuscheriid Soil Ciliates (Ciliophora: Haptorida) from Four Biogeographic Regions

Fuscheriid haptorids are characterized by meridionally extending ciliary rows clearly separated from the dikinetidal circumoral kinety; a two- or three-rowed dorsal brush; and oral basket rods (nematodesmata) originating from both, the circumoral dikinetids and from some oralized monokinetids in the anterior portion of the ciliary rows. Using standard morphological methods, we describe four new fuscheriid taxa, each discovered in a specific biogeographic region. Fuscheriides tibetensis nov. gen., nov. spec. has rod-shaped extrusomes and two dorsal brush rows. It is a small (~ 80 × 10 μm), slender ciliate with only seven ciliary rows, and was discovered in grassland soil of southern Tibet, about 4600 m above sea-level. Aciculoplites ethiopiensis nov. gen., nov. spec. has acicular extrusomes and two dorsal brush rows. It is a middle-sized (~ 100 × 30 μm), oblong ciliate with about 22 ciliary rows, and was discovered in floodplain soil from a lake in Ethiopia. Fuscheria uluruensis nov. spec., which we discovered in mud and aeolic soil from pools on top of the Ayers Rock in the red centre of Australia, is unique in having the macronucleus split into about 12 oblong nodules. The nodules originate post-divisionally via the branching macronucleus strand, as in multinucleate spathidiids. Fuscheria nodosa salisburgensis nov. sspec., which was discovered in mud and soil of a meadow pool in Salzburg (Austria), has a long, tortuous macronucleus and about 45 ciliary rows. The resting cyst has an escape apparatus absent from the cyst of F. uluruensis, indicating that Fuscheria is non-monophyletic

Genealogical analyses of multiple loci of litostomatean ciliates (Protista, Ciliophora, Litostomatea)

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Molecular Phylogenetics and Evolution 66 (2012): 397-411, doi:10.1016/j.ympev.2012.06.024.The class Litostomatea is a highly diverse ciliate taxon comprising hundreds of free-living and endocommensal species. However, their traditional morphology-based classification conflicts with 18S rRNA gene phylogenies indicating (1) a deep bifurcation of the Litostomatea into Rhynchostomatia and Haptoria + Trichostomatia, and (2) body polarization and simplification of the oral apparatus as main evolutionary trends in the Litostomatea. To test whether 18S rRNA molecules provide a suitable proxy for litostomatean evolutionary history, we used eighteen new ITS1-5.8S rRNA-ITS2 region sequences from various free-living litostomatean orders. These single- and multiple-locus analyses are in agreement with previous 18S rRNA gene phylogenies, supporting that both 18S rRNA gene and ITS region sequences are effective tools for resolving phylogenetic relationships among the litostomateans. Despite insertions, deletions and mutational saturations in the ITS region, the present study shows that ITS1 and ITS2 molecules can be used to infer phylogenetic relationships not only at species level but also at higher taxonomic ranks when their secondary structure information is utilized to aid alignment.Financial support was provided by the Austrian Science Foundation (FWF Projects P-19699-B17 and P-20360-B17 to Wilhelm Foissner), the Slovak Scientific Grant Agency (VEGA Project 1/0600/11 to Peter Vd’ačný), and US NSF Grants (Projects MCB-0348341 and DEB-0816840 to Slava S. Epstein)

A Reinvestigation of Neokeronopsis Populations, Including the Description of N. asiatica nov. spec. (Ciliophora, Hypotricha)

We investigated the status of various Neokeronopsis populations, using protargol-impregnated type material, a new Chinese population, and literature data. This resulted not only in the recognition of a new species, Neokeronopsis asiatica, but also in upgrading Afrokeronopsis from subgenus to genus level. The genera Neokeronopsis and Afrokeronopsis differ mainly in the buccal depression (absent vs. present) and in the midventral cirri between proter and opisthe, which are either retained (Afrokeronopsis) or transformed into cirral anlagen (Neokeronopsis). Neokeronopsis asiatica nov. spec. differs from N. spectabilis (Kahl, 1932) by the following features: body size (~ 300 × 120 μm vs. 400 × 170 μm); posterior body end (acute with distinct indentation at site of caudal cirri vs. broadly rounded and without or indistinct indentation); posterior end of marginal rows (ending at different vs. same or similar level); dorsal kinety 1 (continuous vs. fragmented); and the size of the bases of the adoral membranelles (largest membranelles on average 18 μm vs. 29 μm wide). Improved diagnoses are provided for the family Neokeronopsidae and the genera contained therein, viz., Neokeronopsis, Afrokeronopsis, and Pattersoniella. Our study shows the importance of depositing type and voucher material in recognized repositories. Only this will allow future researchers to restudy the populations, for the sake of improved taxonomic and biogeographic knowledge

Five New Spathidiids (Ciliophora: Haptoria) from Caribbean Tank Bromeliads

There is a widespread belief that spathidiids have few morphological features. In contrast, we show a rich morphological diversity in five new species discovered in tank bromeliads from the Caribbean, using live observation; protargol impregnation; morphometry; scanning electron microscopy; and resting cyst morphology, demonstrating lepidosomes (organic scales) for the first time in spathidiid haptoria. Arcuospathidium bromelicola nov. spec. is very similar to the previously described A. muscorum but its resting cyst has conspicuous, pillar-shaped lepidosomes on the surface. Protospathidium lepidosomatum nov. spec. is very similar to the previously described P. muscicola but has outstanding, nipple-shaped (vs. conical) lepidosomes on the cyst surface. Spathidium bromeliophilum nov. spec., whose ontogenesis is highly similar to that of S. turgitorum, differs from similar species by the body length:width ratio, the number of ciliary rows, the shape of the oral bulge, and details of the ciliary pattern. Spathidium bromelicola nov. spec. is similar to S. muscicola (extrusomes bluntly fusiform and 4 µm long vs. rod-shaped and > 15 µm long) and S. stammeri (resting cyst wall smooth vs. spinous). Spathidium wolfi nov. spec. has an anterior and a posterior contractile vacuole. It differs from the supposed nearest relative, S. faurefremieti, by body size (on average 135 × 25 µm vs. 240 × 17 µm), the shape of the macronucleus (moniliform vs. a long, tortuous strand), and the total number of dorsal brush bristles (on average 47 vs. 72). The bent oral bulge of Arcuospathidium bromelicola and Spathidium bromeliophilum as well as the occurrence of lepidosomes on the cyst surface of Arcuospathidium bromelicola and Protospathidium lepidosomatum are discussed

Broad Taxon Sampling of Ciliates Using Mitochondrial Small Subunit Ribosomal DNA

Mitochondrial SSU-rDNA has been used recently to infer phylogenetic relationships among a few ciliates. Here, this locus is compared with nuclear SSU-rDNA for uncovering the deepest nodes in the ciliate tree of life using broad taxon sampling. Nuclear and mitochondrial SSU-rDNA reveal the same relationships for nodes well-supported in previously-published nuclear SSU-rDNA studies, although support for many nodes in the mitochondrial SSU-rDNA tree are low. Mitochondrial SSU-rDNA infers a monophyletic Colpodea with high node support only from Bayesian inference, and in the concatenated tree (nuclear plus mitochondrial SSU-rDNA) monophyly of the Colpodea is supported with moderate to high node support from maximum likelihood and Bayesian inference. In the monophyletic Phyllopharyngea, the Suctoria is inferred to be sister to the Cyrtophora in the mitochondrial, nuclear, and concatenated SSU-rDNA trees with moderate to high node support from maximum likelihood and Bayesian inference. Together these data point to the power of adding mitochondrial SSU-rDNA as a standard locus for ciliate molecular phylogenetic inferences

Soil protistology rebooted: 30 fundamental questions to start with

Protists are the most diverse eukaryotes. These microbes are keystone organisms of soil ecosystems and regulate essential processes of soil fertility such as nutrient cycling and plant growth. Despite this, protists have received little scientific attention, especially compared to bacteria, fungi and nematodes in soil studies. Recent methodological advances, particularly in molecular biology techniques, have made the study of soil protists more accessible, and have created a resurgence of interest in soil protistology. This ongoing revolution now enables comprehensive investigations of the structure and functioning of soil protist communities, paving the way to a new era in soil biology. Instead of providing an exhaustive review, we provide a synthesis of research gaps that should be prioritized in future studies of soil protistology to guide this rapidly developing research area. Based on a synthesis of expert opinion we propose 30 key questions covering a broad range of topics including evolution, phylogenetics, functional ecology, macroecology, paleoecology, and methodologies. These questions highlight a diversity of topics that will establish soil protistology as a hub discipline connecting different fundamental and applied fields such as ecology, biogeography, evolution, plant-microbe interactions, agronomy, and conservation biology. We are convinced that soil protistology has the potential to be one of the most exciting frontiers in biology

Neotypification Of Protists, Especially Ciliates (Protozoa, Ciliophora)

Volume: 59Start Page: 165End Page: 16