Two New Marine Ciliates,Caryotricha rariseta n. sp. and Discocephalus pararotatorius n. sp. (Ciliophora,Spirotrichea), with Phylogenetic Analyses Inferred from the Small Subunit rRNA Gene Sequences

The morphology, infraciliature, and molecular phylogeny of two novel spirotrich ciliates, Caryotricha rariseta n. sp. and Discocephalus pararotatorius n. sp., isolated from coastal waters of China, were investigated. Caryotricha rariseta n. sp. differs from its congeners mainly in possessing seven sparsely ciliated cirral rows that are conspicuously shortened posteriorly and three transverse cirri aligned in a row. Discocephalus pararotatorius n. sp. is characterized by the conspicuous spine‐like dorsal cilia, one extra (endoral?) membrane, and seven frontal, six ventral, and seven posterolateral marginal cirri. The small subunit rRNA gene was sequenced for both species. Complete SSU rRNA gene sequences of two Caryotricha spp. (including C. rariseta n. sp.) and two Discocephalus spp. (including D. pararotatorius n. sp.), along with those of 40 other ciliates, were used to determine their molecular phylogeny using maximum likelihood, neighbor joining and maximum parsimony analyses. The two Caryotricha species cluster with Kiitricha marina in the well‐supported Protohypotrichia clade that is basal to the main spirotrich assemblage. The two discocephalids form a clade that is sister to the Hypotrichia.     

Redescription of Antetintinnidium mucicola (Claparède and Lachmann, 1858) nov. gen., nov. comb. (Alveolata,Ciliophora, Tintinnina)

Tintinnid ciliates have traditionally been described and classified exclusively based on their lorica features. Although information on the cell characters is urgently needed for a natural classification, more molecular than cytological data has been accumulated over recent years. Apparently, the tintinnids developed in the marine environment and entered freshwater several times independently. Typical freshwater tintinnids belong to the genera Tintinnidium and Membranicola. The species are comparatively well‐known regarding their morphology and characterised by two unusual de novo originating ciliary rows, the ventral organelles. In contrast, the cell features in the marine/brackish Tintinnidium species, specifically their somatic ciliary patterns, are insufficiently known or not known at all. Therefore, the morphology of a common marine/brackish representative, Tintinnidium mucicola, is redescribed based on live observation and protargol‐stained material. Furthermore, biogeographical and autecological data of the species are compiled from literature and own records. The phylogenetic relationships of T. mucicola are inferred and the diversity of the family Tintinnidiidae is assessed from 18S rDNA sequences. The study shows that T. mucicola is not only molecularly distinct, but also characterised by many plesiomorphic features, for instance, it does not possess a verifiable homologue to the ventral organelles. Hence, a new genus, Antetintinnidium nov. gen., is established for T. mucicola. The new insights into the diversity of Tintinnidiidae shed light on the early evolution of tintinnids and might provide clues on their adaptions to freshwater.     

Reconsideration of the Phylogenetic Positions of Five Peritrich Genera,Vorticella, Pseudovorticella,Zoothamnopsis, Zoothamnium,and Epicarchesium (Ciliophora,Peritrichia, Sessilida), Based on Small Subunit rRNA Gene Sequences

ABSTRACT. In order to re‐evaluate the systematics of sessilid peritrich ciliates, small subunit (SSU) rRNA gene sequences were determined for 12 species belonging to five genera: Vorticella, Pseudovorticella, Epicarchesium, Zoothamnium, and Zoothamnopsis. Phylogenetic trees were deduced using Bayesian inference, maximum parsimony, and maximum likelihood methods. The phylogenetic analyses suggest that (1) sessilids which have stalks with continuous myonemes that contract in a zig‐zag fashion form a separate clade from those which have stalks that contract independently and in a spiral fashion, supporting the separation of the family Zoothamniidae from the family Vorticellidae and (2) Epicarchesium and Pseudovorticella, both of which have reticulate silverline systems, are more closely related to each other than to other vorticellids, suggesting that differences in the silverline system (i.e. transverse vs. reticulate) may be the result of genuine evolutionary divergence among sessilid peritrichs. However, the newly sequenced Zoothamnopsis sinica, which has a reticulate silverline pattern, nests within the unresolved Zoothamnium species that have transverse silverline patterns. Thus, there were at least two evolutions of the reticulate silverline pattern character state from a plesiomorphic transverse state in the peritrichid ciliates. The molecular work demonstrates the genus Zoothamnium to be paraphyletic in relation to morphological studies, and suggests that Astylozoon, Opisthonecta, and Vorticella microstoma possibly share a SSU rRNA secondary structure in the helix E10‐1 region.     

Trichopodiella faurei n. sp. (Ciliophora,Phyllopharyngea, Cyrtophoria): Morphological Description and Phylogenetic Analyses Based on SSU rRNA and Group I Intron Sequences

ABSTRACT. A new marine cyrtophorian ciliate Trichopodiella faurei n. sp., which belongs to the order Dysteriida, family Hartmannulidae, was investigated at the morphological and molecular levels. A combination of morphological features of the organism including the oval body shape, 2–3 contractile vacuoles, 22–28 nematodesmal rods in the cytopharyngeal basket, and 31–39 somatic kineties, distinguishes it from all other known congeners. In reconstructed small subunit (SSU) rRNA phylogenies, T. faurei groups with Isochona, a representative genus of the subclass Chonotrichia. The similarity of the infraciliature between hartmannulids and several chonotrichian examples also suggests that these taxa should be closely related. A new S943 intron belonging to group IC1 was identified in the SSU rRNA gene of this species. This intron is phylogenetically related to the S891 introns previously found in the suctorians Acineta sp. and Tokophrya lemnarum, and their internal guide sequences share four nucleotides, indicating that these introns were vertically inherited from a common phyllopharyngean ancestor and that reverse splicing might have been involved in the transposition.     

Phylogenetic Investigations on Ten Genera of Tintinnid Ciliates (Ciliophora: Spirotrichea: Tintinnida), Based on Small Subunit Ribosomal RNA Gene Sequences

Tintinnida is a diverse taxon that accommodates over 1,500 morphospecies, which is an important component of marine planktonic food webs. However, evolutionary relationships of tintinnids are poorly known because molecular data of most groups within this order are lacking. In our study, the small subunit (SSU) rRNA genes representing 10 genera, 5 families of Tintinnida were sequenced, including the first SSU rRNA gene sequences for Coxliella, Dadayiella, Epiplocyloides, and Protorhabdonella, and phylogenetic trees were constructed to assess their intergeneric relationships. Phylogenies inferred from different methods showed that (1) Three newly sequenced Eutintinnus species fell into Eutintinnus clade forming a sister group to the clade containing Amphorides, Steenstrupiella, Amphorellopsis, and Salpingella; (2) Surprisingly, the genetic distances between Amphorides amphora and Amphorellopsis acuta population 1 was even smaller than that between the two populations of Amphorellopsis acuta, casting doubt on the validity of Amphorides and Amphorellopsis as presently defined; (3) The SSU rRNA sequences of Dadayiella ganymedes and Parundella aculeata were almost identical. Therefore, Parundella ganymedes novel combination is proposed; (4) Coxliella, which is currently assigned within Metacylididae, branched instead with some Tintinnopsis species. Furthermore, the validation of Coxliella, which was considered to be a “questionable” genus, was confirmed based on evidences from morphology, ecology, and molecular data; (5) Protorhabdonella and Rhabdonella showed rather low intergeneric distance and grouped together with strong support suggesting that Rhabdonellidae is a well‐defined taxon; and (6) Epiplocyloides branched with species in Cyttarocylididae indicating their close relationship.     

Morphology and Small Subunit rDNA Gene Sequence of Pseudoamphisiella quadrinucleata n. sp. (Ciliophora,Urostylida) from the South China Sea

ABSTRACT. The urosylid genus Pseudoamphisiella was established by Song (1996) with hitherto only two known congeners. In the present work, the morphology and infraciliature of a new member, Pseudoamphisiella quadrinucleata n. sp., a form with conspicuous alveolar layer and four macronuclear nodules isolated from the coastal waters both near Hong Kong and near Guangzhou, South China were investigated using living observation and protargol silver impregnation methods. Pseudoamphisiella quadrinucleata differs from other two known forms mainly by the number of macronuclear nodules: constantly four vs. two in Pseudoamphisiella alveolata and 24–57 in Pseudoamphisiella lacazei. To support this, the sequence of the small subunit rDNA of P. quadrinucleata n. sp. showed 14 and 74 nucleotides in comparison with that of the two known congeners, respectively, which hence firmly supports the validity of the new species.     

Phylogenetic Relationships of Orders Within the Class Colpodea (Phylum Ciliophora) Inferred from Small Subunit rRNA Gene Sequences

Molecular analyses have been used recently to refine our knowledge of phylogenetic relationships within the ciliated protozoa (phylum Ciliophora). A current Hennigian phylogeny of the orders in the class Colpodea, based on light and electron microscopic analyses, makes three important assumptions with regard to apomorphic character states, namely, (1) that the kreyellid silver line evolved early in colpodean phylogeny, separating bryometopids, such as Bryometopus, from all other colpodeans; (2) that the macro–micronuclear complex is an autapomorphy of the cyrtolophosidids, such as Platyophrya; and (3) that merotelokinetal stomatogenesis is an apomorphic character of colpodids, such as Colpoda, Bresslaua, and Pseudoplatyophrya. These predictions of relationships within the class Colpodea were investigated by determining the complete small subunit rRNA gene sequences for the colpodid Bresslaua vorax, the grossglockneriid Pseudoplatyophrya nana, and the cyrtolophosidid Platyophrya vorax and a partial sequence for the bryometopid Bryometopus sphagni. These sequences were combined with the previously published complete SSrRNA sequences for the colpodid Colpoda inflata and the bursariomorphid Bursaria truncatella. The affiliations were assessed using both distance matrix and maximum-parsimony analyses. The tree topologies for the class Colpodea were identical in all analyses, with bootstrap support for bifurcations always exceeding 60%. The results suggest the following. (1) Since the clade including Bryometopus and its sister taxon, Bursaria, is never basal, the kreyellid silver-line system evolved later in colpodean phylogeny and does not separate bryometopids from all other colpodeans. (2) Since Platyophrya is always the sister taxon to the other five genera, there is a fundamental phylogenetic significance for its macro–micronuclear complex. (3) Since the colpodids, Colpoda, Bresslaua, and Pseudoplatyophrya, always group in one clade, merotelokinetal stomatogenesis appears to be a derived character state. Received: 30 June 1998 / Accepted: 3 December 1998     

The morphology, ontogeny, and small subunit rRNA gene sequence analysis of Diophrys parappendiculata n. sp. (Protozoa, Ciliophora, Euplotida), a new marine ciliate from coastal waters of southern China

The morphology, morphogenesis, and phylogeny of Diophrys parappendiculata n. sp., a large marine ciliate isolated from the coastal waters of Daya Bay, southern China, were investigated. This new species is characterized by a combination of its large size, appendiculata-pattern of ciliature, and bipartite adoral zone of membranelles. The main stages of morphogenesis during binary fission were also recorded and described. Comparisons of morphological characteristics with similar congeners support the validity of the new species. The small subunit rRNA gene sequence of D. parappendiculata is 96.3-99.94% similar to those of four other congeners; it differs in four nucleotides from that of Diophrys appendiculata (i.e. structural similarity was 99.94%). Phylogenetic analysis indicates that D. parappendiculata n. sp. falls into the Diophrys clade and is most closely related to the well-known D. appendiculata.     

Phylogenetic Relationships of the Nassulida Within the Phylum Ciliophora Inferred from the Complete Small Subunit rRNA Gene Sequences of Furgasonia blochmanni, Obertrumia georgiana, and Pseudomicrothorax dubius

ABSTRACT. Using comparisons of complete small subunit rRNA sequences from the ciliated protozoans Furgasonia blochmanni, Obertrumia georgiana , and Pseudomicrothorax dubius we inferred the phylogenetic position of the Nassulida (Class Nassophorea) within the Ciliophora. In distance matrix analyses the Nassulida share a common ancestry with the colpodean ciliate Colpoda inflata. Distance matrix and parsimony methods convincingly demonstrate that the Nassulida plus Colpodida are members of a complex ciliate assemblage that also includes the oligohymenophorans and phyllopharyngeans. These phylogenetic inferences are largely congruent with recent analyses of 23S-like rRNA gene sequences and morphogenetic features. Groups traditionally thought to represent ancestral lineages now appear as highly derived ciliates. In contrast, heterotrichs which were considered to represent a highly evolved group, diverge at the base of the ciliates.     

Phylogenetic Analyses Based on Small Subunit rRNA and Glycosomal Glyceraldehyde-3-Phosphate Dehydrogenase Genes and Ultrastructural Characterization of Two Snake Trypanosomes: Trypanosoma serpentis n. sp. from Pseudoboa nigra and Trypanosoma cascavelli from Crotalus durissus terrificus

ABSTRACT. We sequenced the small subunit (SSU) rRNA and glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) genes of two trypanosomes isolated from the Brazilian snakes Pseudoboa nigra and Crotalus durissus terrificus . Trypanosomes were cultured and their morphometrical and ultrastructural features were characterized by light microscopy and scanning and transmission electron microscopy. Phylogenetic trees inferred using independent or combined SSU rRNA and gGAPDH data sets always clustered the snake trypanosomes together in a clade closest to lizard trypanosomes, forming a strongly supported monophyletic assemblage (i.e. lizard–snake clade). The positioning in the phylogenetic trees and the barcoding based on the variable V7–V8 region of the SSU rRNA, which showed high sequence divergences, allowed us to classify the isolates from distinct snake species as separate species. The isolate from P. nigra is described as a new species, Trypanosoma serpentis n. sp., whereas the isolate from C. d. terrificus is redescribed here as Trypanosoma cascavelli .     

Alpha‐Tubulin and Small Subunit rRNA Phylogenies of Peritrichs Are Congruent and Do Not Support the Clustering of Mobilids and Sessilids (Ciliophora,Oligohymenophorea)

ABSTRACT. Peritrich ciliates have been traditionally subdivided into two orders, Sessilida and Mobilida within the subclass Peritrichia. However, all the existing small subunit (SSU) rRNA phylogenetic trees showed that the sessilids and mobilids did not branch together. To shed some light on this disagreement, we tested whether or not the classic Peritrichia is a monophyletic group by assessing the reliability of the SSU rRNA phylogeny in terms of congruency with α‐tubulin phylogeny. For this purpose, we obtained 10 partial α‐tubulin sequences from peritrichs and built phylogenetic trees based on α‐tubulin nucleotide and amino acid data. A phylogenetic tree from the α‐tubulin and SSU rRNA genes in combination was also constructed and compared with that from the SSU rRNA gene using a similar species sampling. Our results show that the mobilids and sessilids are consistently separated in all trees, which reinforces the idea that the peritrichs do not constitute a monophyletic group. However, in all α‐tubulin gene trees, the urceolariids and trichodiniids do not group together, suggested mobilids may not be a monophyletic group.     

Phylogenetic relationships of the subclass Peritrichia (Oligohymenophorea, Ciliophora) inferred from small subunit rRNA gene sequences

The phylogenetic relationships among peritrichs remain unresolved. In this study, the complete small subunit rRNA (SSrRNA) gene sequences of seven species (Epistylis galea, Campanella umbellaria, Carchesium polypinum, Zoothamnium arbuscula, Vaginicola crystallina, Ophrydium versatile, and Opercularia microdiscum) were determined. Trees were constructed using distance-matrix, maximum-likelihood and maximum-parsimony methods, all of which strongly supported the monophyly of the subclass Peritrichia. Within the peritrichs, 1) E. galea grouped with Opercularia microdiscum and Campanella umbellaria but not the other Epistylis species, which indicates that the genus Epistylis might not be monophyletic; 2) the topological position of Carchesium and Campanella suggested that Carchesium should be placed in the family Zoothamniidae, or be elevated to a higher taxonomic rank, and that Campanella should be independent of the family Epistylididae, and probably be given a new rank; and 3) Opisthonecta grouped strongly with Astylozoon, which suggested that Opisthonecta species were not the ancestors of the stalked peritrichs.     

Phylogeny and Establishment of a New Ciliate Family,Wilbertomorphidae fam. nov. (Ciliophora,Karyorelictea), a Highly Specialized Taxon Represented by Wilbertomorpha colpoda gen. nov., spec. nov.

The morphology and molecular phylogeny of a new marine interstitial karyorelictean ciliate, Wilbertomorpha colpoda gen. nov., spec. nov., isolated from a sandy beach at Qingdao, China, are investigated. The ciliature is mainly on the right surface with the left surface barren except for a single marginal kinety, which is typical of the order Loxodida. Nevertheless, other morphological features, such as the highly reduced buccal structure, the absence of a buccal cavity and the presence of extremely specialized cortical granules, prevent its assignation to any known family. Furthermore, the secondary structure of the variable region 2 of the SSU rRNA gene is unique among loxodids. Thus, we establish a new family, Wilbertomorphidae fam. nov. for the genus Wilbertomorpha. Phylogenetic analyses based on SSU rRNA gene sequence data suggest that this taxon is a sister group to the family Geleiidae which belongs to the order Protoheterotrichida. However, morphologically Wilbertomorpha bears a much stronger resemblance to Loxodidae which belongs to the order Loxodida. Based on these findings, we tentatively place Wilbertomorphidae nov. fam. incertae sedis within Karyorelictea.     

Morphology,Morphogenesis and Small Subunit rRNA Gene Sequence of a Soil Hypotrichous Ciliate,Perisincirra paucicirrata (Ciliophora,Kahliellidae), from the Shoreline of the Yellow River,North China

The morphology, morphogenesis, and 18S rRNA gene sequence of a soil hypotrichous ciliate Perisincirra paucicirrata, isolated from north China, were investigated. Perisincirra paucicirrata differs from its congeners in: (1) having a body length to width ratio in vivo of 4:1, (2) its adoral zone occupying between 15% and 25% of the total body length, and (3) the presence of two parabuccal cirri, three left (with 10–16 cirri each) and two right marginal rows (with 14–24 cirri each), and three dorsal kineties. Our study offers a first attempt to begin to map the morphogenetic processes of the genus, which are mainly characterised by the following: the formation of four frontal ventral transverse anlagens for each daughter cell, with the proter's anlage I originating from the reorganised anterior part of the parental paroral; the paroral and endoral anlage developed from the reorganised old endoral and do not contribute the first frontal cirrus; the frontoventral transverse anlage I contributing the left frontal cirrus; anlage II generating the middle frontal and the buccal cirri; anlage III developing the right frontal cirrus and the anterior parabuccal cirrus; and anlage IV contributing the posterior parabuccal cirrus. As an additional contribution, we judge that the inner one or the two right rows of P. kahli and P. longicirrata are marginal rows. Phylogenetic analysis based on SSU rDNA sequences suggests that Perisincirra is related to sporadotrichids, but provides no credible evidence for its taxonomic position.     

基于16S rRNA序列的角蟾科部分属间系统关系

采用最大似然法(ML法)、最大简约法(MP法)、邻接法(NJ法)对来自角蟾科Megophryidae(Anura)8属17种及外群2种共25条400bp左右的线粒体16S rRNA序列进行系统发育关系分析。结果表明,用于分析的所有角蟾科物种形成两大支,第一支包括Megophrys,Brachytarsophrys和Atympanophrys,第二支包括Leptobrachium,Leptolalax,Scutiger,Oreolalax和Vibrissaphora。支持将角蟾科划分为两大类群,即第一支属于Megophryini族．第二支属于Leptobrachiini族。根据分子钟模型初步推测两类群问的分歧时间大致为14．2～18．7百万年前。在Megophryini族中,基因树的拓扑结构不支持Atympanophrys建立后的Megophrys为单系;而在Leptobrachiini族中,Leptolalax为一有效属,其系统发生较早。     

Relationships of the Insect-Pathogenic Order Entomophthorales (Zygomycota, Fungi) Based on Phylogenetic Analyses of Nuclear Small Subunit Ribosomal DNA Sequences (SSU rDNA)

We sequenced the nuclear small subunit of ribosomal DNA (SSU rDNA) from seven species within the insect-pathogenic order Entomophthorales. These sequences were aligned with other published SSU rDNA sequences and phylogenies were inferred using phenetic and cladistic methods. Based on three different phylogenetic methods the Entomophthorales (excludingBasidiobolus ranarum) is monophyletic;B. ranarumwas more closely related to chytrids from Chytridiales and Neocallimasticales than to Entomophthorales, as was proposed by Nagahamaet al.(Mycologia87:203–209, 1995). Nuclear characters (large nuclei containing conspicuous condensed chromatin and lack of a prominent nucleolus) were of predictive value for the monophyly of the family Entomophthoraceae. Conidial characters separate the Entomophthoraceae, which only includes obligate pathogens, into at least two lineages: one lineage with uninucleate conidia and another with multinucleate conidia. The two species ofConidiobolusstudied were paraphyletic in our analyses and only distantly related to each other. This information may prove to be important in the use of these fungi as biocontrol agents.     

Redescription of Rigidohymena inquieta (Stokes, 1887) Berger, 2011 as Metahymena inquieta gen. nov., comb. nov. (Ciliophora,Hypotricha) Based on Morphology,Morphogenesis, and Molecular Phylogeny

The morphology and morphogenesis of Rigidohymena inquieta (Stokes, 1887) Berger, 2011, isolated from a lawn soil in the campus of the University of Ulsan, Korea, was studied, using live observation and protargol impregnation. The molecular phylogeny was studied based on the SSU rRNA gene sequences. The morphology of the Korean population of R. inquieta matches the previously known populations; however, the morphogenetic pattern shows differences to the species R. candens in the involvement of cirrus V/3 in the anlagen formation. A novel genus namely Metahymena gen. nov. has been erected for the present species based on the ontogenetic difference, and the new combination Metahymena inquieta gen. nov., comb. nov. is proposed. The morphology, morphogenesis, distribution, and phylogeny of M. inquieta are presented. The morphologic and morphogenetic data corroborate the phylogenetic analyses as M. inquieta clusters among the stylonychid ciliates in a clade distant from Rigidohymena candens.     

A New Genus of Marine Scuticociliate (Protozoa, Ciliophora) from Northern China, with a Brief Note on Its Phylogenetic Position Inferred from Small Subunit Ribosomal DNA Sequence Data

ABSTRACT. The morphology, infraciliature, and silverline system of a new marine scuticociliate, Wilbertia typica n. g., n. sp., collected from coastal waters off northern China, were investigated. The new genus Wilbertia is characterized as follows: sculptured and dorso-ventrally flattened body; dominant buccal field that is almost completely surrounded by the paroral membrane; three apically positioned long membranelles, arranged in parallel; membranelle (M)1 and M2 prominent, M3 small; reticulate silverline system. The type species W. typica n. sp. is defined by having a conspicuous anterior beak-like protrusion; five to eight caudal cilia; M1 four-rowed, M2 two-rowed; M3, single-rowed, bipartite; 15 or 16 somatic kineties; contractile vacuole positioned just posterior to the buccal field; globular macronucleus. The small subunit ribosomal DNA sequence of W. typica is 98.5% similar to the similar morphotype, Eurystomatella sinica . Phylogenetic analyses indicate that Wilbertia groups with Eurystomatella sinica forming a branch that diverges at a deep level from all other pleuronematid scuticociliates. The molecular and morphological data indicate that Wilbertia should be placed within the family Eurystomatidae, which is closely related to the well-known Cyclidiidae.     

Phylogenetic confirmation of the genus Robbea (Nematoda: Desmodoridae,Stilbonematinae) with the description of three new species

ABSTRACT

The Stilbonematinae are a monophyletic group of marine nematodes that are characterized by a coat of thiotrophic bacterial symbionts. Among the ten known genera of the Stilbonematinae, the genus Robbea Gerlach 1956 had a problematic taxonomic history of synonymizations and indications of polyphyletic origin. Here we describe three new species of the genus, R. hypermnestra sp. nov., R. ruetzleri sp. nov. and R. agricola sp. nov., using conventional light microscopy, interference contrast microscopy and SEM. We provide 18S rRNA gene sequences of all three species, together with new sequences for the genera Catanema and Leptonemella. Both our morphological analyses as well as our phylogenetic reconstructions corroborate the genus Robbea. In our phylogenetic analysis the three species of the genus Robbea form a distinct clade in the Stilbonematinae radiation and are clearly separated from the clade of the genus Catanema, which has previously been synonymized with Robbea. Surprisingly, in R. hypermnestra sp. nov. all females are intersexes exhibiting male sexual characters. Our extended dataset of Stilbonematinae 18S rRNA genes for the first time allows the identification of the different genera, e.g. in a barcoding approach.

http://zoobank.org/urn:lsid:zoobank.org:pub:D37C3F5A-CF2B-40E6-8B09-3C72EEED60B0