Helmut Berger

Cladistic relationships and generic characterization of oxytrichid hypotrichs (protozoa, ciliophora)

Summary The relationships of 13 common oxytrichid genera were analysed using cladistic methods (Hennig, PAUP). Twenty-three characters in four groups were selected, viz. the morphology of the oral apparatus (three characters), infraciliature of ventral and dorsal side (ten characters), cortical features (two characters), and ontogenetic particulars (eight characters). All characters and character states are described and discussed using published and original data. Half of the characters originated independently in several genera at least twice, making it very difficult to follow oxytrichid evolution. The autapomorphies of the family Oxytrichidae are 18 characteristically arranged fronto-ventral-transverse cirri and the fragmentation of at least one dorsal kinety. The cladograms show two major branches, termed subfamily Oxytrichinae Jankowski and subfamily Stylonychinae n. subfam. The Oxytrichinae have a unique synapomorphy, viz. the participation of cirrus V/3 in primordia formation. This subfamily contains the genera Cyrtohymena, Gonostomum, Notohymena, Onychodromopsis, Oxythcha, Tachysoma, Urosoma, Urosomoida and, very likely, Australocirrus, Parurosoma and Pseudostrombidium . The Stylonychinae have three synapomorphies, viz. the rigid body, an oral apparatus of more than 40% of body length, and the lack of cortical granules. This subfamily comprises Coniculostomum, Histriculus, Steinia, Sterkiella, Stylonychia and, very likely, Parastylonychia and Pleurotricha . The family Oxytrichidae, its subfamilies, and the genera included are characterized and keyed. An unambiguous terminology is established for oxytrichid hypotrichs, and synonymy and nomenclature of genera are discussed.

Monograph of the Gonostomatidae and Kahliellidae (Ciliophora, Hypotricha)

A General Section.- B Systematic Section.- Gonostomatidae (33 species).- Kahliellidae (15 species).- Taxa of Unknown Position in the Non-dorsomarginalian Hypotricha (14 species).- Supplement to Apourosomoida (5 species).- References.- Systematic Index.- Table Index.

Three-gene based phylogeny of the Urostyloidea (Protista, Ciliophora, Hypotricha), with notes on classification of some core taxa

Classifications of the Urostyloidea were mainly based on morphology and morphogenesis. Since molecular phylogeny largely focused on limited sampling using mostly the one-gene information, the incongruence between morphological data and gene sequences have risen. In this work, the three-gene data (SSU-rDNA, ITS1-5.8S-ITS2 and LSU-rDNA) comprising 12 genera in the core urostyloids are sequenced, and the phylogenies based on these different markers are compared using maximum-likelihood and Bayesian algorithms and tested by unconstrained and constrained analyses. The molecular phylogeny supports the following conclusions: (1) the monophyly of the core group of Urostyloidea is well supported while the whole Urostyloidea is not monophyletic; (2) Thigmokeronopsis and Apokeronopsis are clearly separated from the pseudokeronopsids in analyses of all three gene markers, supporting their exclusion from the Pseudokeronopsidae and the inclusion in the Urostylidae; (3) Diaxonella and Apobakuella should be assigned to the Urostylidae; (4) Bergeriella, Monocoronella and Neourostylopsis flavicana share a most recent common ancestor; (5) all molecular trees support the transfer of Metaurostylopsis flavicana to the recently proposed genus Neourostylopsis; (6) all molecular phylogenies fail to separate the morphologically well-defined genera Uroleptopsis and Pseudokeronopsis; and (7) Arcuseries gen. nov. containing three distinctly deviating Anteholosticha species is established.

Morphologic and Biometric Characterization of Twenty-four Soil Testate Amoebae (Protozoa, Rhizopoda)

Summary 24 soil dwelling testate amoebae, belonging to 34 populations, are described and biometrically characterized. An “ideal individual” for each of the investigated species is constructed by means of the biometric data. Species separation in the Nebela tincta-parvula-bohemica-collaris group is discussed in detail. In Plagiopyxis declivis, idiosomes of euglyphids occur between the xenosomes of the shell. The analysis of the coefficients of variation of all species shows the lowest variation for the length of the shell and the highest values for its aperture. In general, the Testaceafilosa and shells composed of idiosomes have wider ranges of variation as compared with the Testacealobosa and species covered with xenosomes. This indicates that the Testaceafilosa evolve faster or are evolutionary younger than the Testacealobosa. Pseudodifflugia fascicularis, Euglypha strigosa and Difflugia lucida have only 1 central nucleolus, which contrasts with earlier data from literature. Significant differences between populations of the same species were found and indicate the existence of several geographical races which differ only in their size.

Redefinition of Holosticha Wrzesniowski, 1877 (Ciliophora, Hypotricha)

A revision of the urostylid hypotrichs showed that at present Holosticha is characterized by an unspecified combination of plesiomorphies. Thus more than 100 species have been originally described in this genus, and about 49 species are currently recognised. However, a detailed comparison of the descriptions showed that Holosticha comprises only 7 species unified by a highly characteristic combination of apomorphies (e.g. anterior end of left marginal row curved rightwards, adoral zone bipartite, buccal cirrus distinctly ahead of paroral) and plesiomorphies. The other species at present included in Holosticha are assigned to Anteholosticha nov. gen. (29 species), Caudiholosticha nov. gen. (10 species), and Biholosticha nov. gen. (2 species).

A huge, undescribed soil ciliate (Protozoa: Ciliophora) diversity in natural forest stands of Central Europe

AbstractWe investigated 12 natural forest stands in eastern Austria for soil ciliate diversity, viz., eight beech forests and two lowland and Pinus nigra forests each. The stands span a wide range of climatic (e.g., 543–1759 mm precipitation, 160–1035 m above sea-level) and abiotic (e.g., pH 4–7.4) factors. Samples were taken twice in autumn and late spring and analysed with the non-flooded Petri dish method. Species were identified in vivo, in silver preparations, and in the scanning electron microscope. A total of 233 species were found, of which 30 were undescribed, a surprising number showing our ignorance of soil ciliate diversity, even in Central Europe. Species number varied highly from 45 (acidic beech on silicate) to 120 (floodplain forest) and was strongly correlated with pH and overall habitat quality, as measured by climate, the C/P quotient (ratio of r-selected colpodean and k-selected polyhymenophorean ciliates), and the proportion of mycophagous ciliate species; multivariate analysis showed further important variables, viz., the general nutrient status (glucose, nitrogen, C/nN ratio) and microbial (urease) activity. The highest species number occurred in one of the two floodplain soils, supporting the intermediate disturbance hypothesis. The three main forest types could be clearly distinguished by their ciliate communities, using similarity indices and multidimensional scaling. Individual numbers varied highly from 135−1 (lowland forest) to 10,925 ml−1 (beech on silicate) soil percolate and showed, interestingly, a weak correlation with soil protozoan phospholipid fatty acids. Eight of the 30 new species found and a forgotten species, Arcuospathidium coemeterii (Kahl 1943) nov. comb., are described in detail, as examples of how species were recognized and soil protozoan diversity should be analyzed: Latispathidium truncatum bimicronucleatum, Protospathidium fusioplites, Erimophrya sylvatica, E. quadrinucleata, Paragonostomum simplex, Periholosticha paucicirrata, P. sylvatica, and Australocirrus zechmeisterae.

Redefinition and Reassignment of the 18-cirri Genera Hemigastrostyla, Oxytricha, Urosomoida, and Actinotricha (Ciliophora, Hypotricha), and Description of One New Genus and Two New Species

The morphology, the infraciliature, and two stages of physiological reorganization of Hemigastrostyla elongata spec. nov., isolated from the Yellow Sea near Qingdao (China), are described. The new species differs from the type H. stenocephala, inter alia, by the length of the dorsal bristles and the position of the pretransverse ventral cirri; from H. enigmatica by the number of caudal cirri; and from H. para-enigmatica spec. nov. - established for the H. enigmatica populations from the Yellow Sea - by the arrangement of the postoral ventral cirri and the cortical granulation. A key to the Hemigastrostyla species and some other 18-cirri hypotrichs is provided. Hemigastrostyla szaboi is fixed as type species of Heterooxytricha gen. nov. because the type population lacks the extra cirri which are characteristic for Hemigastrostyla. In addition, Oxytricha geleii is assigned to this new genus, whose species have, like many oxytrichids, 18 frontal-ventraltransverse cirri, but a Gonostomum dorsal kinety pattern. The old, large, and difficult genus Oxytricha is briefly reviewed, mainly on the basis of the dorsal kinety pattern. Very likely, only species with the Oxytricha pattern belong to this genus. Oxytricha marcili and O. pseudofurcata, which have the Urosomoida kinety pattern (i.e. kinety 3 fragmentation lacking), are transferred to Urosomoida which is, inter alia, defined by a more or less distinctly reduced number of ventral and transverse cirri. Some other Oxytricha species with this kinety pattern (O. islandica, O. lanceolata, O. pseudosimilis, O. setigera) are not transferred to Urosomoida, but preliminarily classified as incertae sedis in Oxytricha, because they have the full set of 18 cirri. The available molecular data on O. lanceolata indicate that this type of 18-cirri hypotrichs likely needs a genus of its own because O. lanceolata does not cluster with O. granulifera, type of this genus. The marine Actinotricha saltans, classified for a very long time in Oxytricha, seems to be a non-dorsomarginalian hypotrich according to molecular data, justifying the reactivation of the old genus Actinotricha. Oxytricha shii has a multiple dorsal kinety 3 fragmentation, three dorsomarginal rows, and the undulating membranes arranged in the Cyrtohymena pattern, strongly indicating that it is a member of the subgenus Cyrtohymena (Cyrtohymenides). This brief review is a further step to unravel the complicated systematics of the old, but still little-known genus Oxytricha. The following new combinations are made in this paper: Cyrtohymena (Cyrtohymenides) shii (Shi et al., 1997) comb. nov.; Heterooxytricha szaboi (Wilbert and Song, 2005) comb. nov.; Heterooxytricha geleii (Wilbert, 1986) comb. nov.; Urosomoida marcili (Paiva and Silva-Neto, 2004) comb. nov.; Urosomoida pseudofurcata (Berger, 1999) comb. nov.

Genetic, Morphological, and Ecological Diversity of Spatially Separated Clones of Meseres corlissi Petz & Foissner, 1992 (Ciliophora, Spirotrichea)

ABSTRACT. We investigated the intraspecific variation of the spirotrich freshwater ciliate Meseres corlissi at the level of genes (SSrDNA, ITS), morphology (14 characters), and ecophysiology (response to temperature and pH). Five of the eight clonal M. corlissi cultures isolated from five localities on four continents were studied at all levels. The null hypothesis was that geographic distance plays no role: M. corlissi lacks biogeography. The intraspecific variation was low at the genetic level (0%–4%), moderate at the morphological level (5%–15%), and high at the ecophysiological level (10%–100%). One clone, isolated from subtropical China, differed significantly at all levels from all other clones, suggesting limited dispersal and local adaptation among M. corlissi. However, other clones from distant areas, such as Australia and Austria, were genetically identical and differed only slightly in morphology and temperature response. We speculate that our findings may be typical for rare species; the chances may be equally high for both global dispersal of most and local adaptation of some populations in areas where dispersal has been permanently or temporarily reduced.

Systematics and species-specific response to pH of Oxytricha acidotolerans sp. nov. and Urosomoida sp. (Ciliophora, Hypotricha) from acid mining lakes

We investigated the morphology, phylogeny of the 18S rDNA, and pH response of Oxytricha acidotolerans sp. nov. and Urosomoida sp. (Ciliophora, Hypotricha) isolated from two chemically similar acid mining lakes (pH ∼ 2.6) located at Langau, Austria, and in Lusatia, Germany. Oxytricha acidotolerans sp. nov. from Langau has 18 frontal-ventral-transverse cirri but a very indistinct kinety 3 fragmentation so that the assignment to Oxytricha is uncertain. The somewhat smaller species from Lusatia has a highly variable cirral pattern and the dorsal kineties arranged in the Urosomoida pattern and is, therefore, preliminary designated as Urosomoida sp. The pH response was measured as ciliate growth rates in laboratory experiments at pH ranging from 2.5 to 7.0. Our hypothesis was that the shape of the pH reaction norm would not differ between these closely related (3% difference in their SSU rDNA) species. Results revealed a broad pH niche for O. acidotolerans, with growth rates peaking at moderately acidic conditions (pH 5.2). Cyst formation was positively and linearly related to pH. Urosomoida sp. was more sensitive to pH and did not survive at circumneutral pH. Accordingly, we reject our hypothesis that similar habitats would harbour ciliate species with virtually identical pH reaction norm.

Molecular Phylogeny and Ontogeny of a New Ciliate Genus, Paracladotricha salina n. g., n. sp. (Ciliophora, Hypotrichia)

A hypotrichous ciliate, Paracladotricha salina n. g., n. sp., was discovered in hypersaline waters (salinity about 80‰) from Qingdao, China. Its morphology and some major ontogenetic stages were studied and the phylogenetic position was estimated using standard methods. Paracladotricha salina is characterized by a flexible, more or less slender body (size 50–120 × 20–35 μm), a gonostomatid oral apparatus, one short and two long frontoventral rows, four macronuclear nodules, almost completely reduced dorsal kineties 1–3, and a loss of several parts of the ciliature, namely, the slightly shortened ciliary row of the adoral membranelles, the paroral, and the buccal, the postoral and pretransverse ventral, the transverse, and the caudal cirri. The ontogenesis is rather simple: anlage II of both filial products and anlage III of the opisthe originate de novo, while anlagen IV and V are formed within the parental rows. This combination of features requires the establishment of a new genus, Paracladotricha, which is, according to the morphological data, closely related to Schmidingerothrix and Cladotricha. The small‐subunit rRNA gene was sequenced, indicating that P. salina is, as also demonstrated by the oral apparatus, a member of the gonostomatids. We provide a first, vague hypothesis about the phylogenetic relationships of the Gonostomatidae, Cladotrichidae, and Schmidingerotrichidae. However, since molecular data of the type species of these higher taxa are lacking, their validity and relationships remain obscure.