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In recent years, Tetrahymena species have been used as model organisms for research in a wide range of fields, highlighting the need for a fuller understanding of the taxonomy of this group. It is in this context that this paper uses living observation and silver staining methods to investigate the morphology and infraciliature of one Tetrahymena species, T. setosa (Schewiakoff 1892 Verh. Naturh. Med. Ver. Heidelb., 4:544) McCoy (1975) Acta Protozool., 14:253; the senior subjective synonym of T. setifera Holz and Corliss (1956) J. Protozool., 3:112; isolated from a freshwater pond in Harbin, north‐eastern China. This organism can be distinguished from other described Tetrahymena species mainly by its single caudal cilium, which is about twice the length of the somatic ciliature. While the Harbin isolate appears similar to the population described by Holz and Corliss (1956) J. Protozool., 3:112, an improved diagnosis for T. setosa is given based on the previous descriptions and the Harbin population. In summary, this species can be recognized mainly by the combination of the following characters: body in vivo approximately 40 μm × 25 μm, 21–26 somatic kineties, one to four contractile vacuole pores associated with meridians 6–11 and a single caudal cilium. The small subunit ribosomal (SSU) rRNA gene and the cox1 gene sequences of Harbin population are also characterized in order to corroborate that the isolated species branches in phylogenetic trees as a T. setosa species. The phylogenetic analysis also indicated that sequences of populations of Tetrahymena species should be published with detailed morphological identifications. [ABSTRACT FROM AUTHOR]

Recent advances in molecular technology have revolutionized research on all aspects of the biology of organisms, including ciliates, and created unprecedented opportunities for pursuing a more integrative approach to investigations of biodiversity. However, this goal is complicated by large gaps and inconsistencies that still exist in the foundation of basic information about biodiversity of ciliates. The present paper reviews issues relating to the taxonomy of ciliates and presents specific recommendations for best practice in the observation and documentation of their biodiversity. This effort stems from a workshop that explored ways to implement six Grand Challenges proposed by the International Research Coordination Network for Biodiversity of Ciliates ( IRCN- BC). As part of its commitment to strengthening the knowledge base that supports research on biodiversity of ciliates, the IRCN- BC proposes to populate The Ciliate Guide, an online database, with biodiversity-related data and metadata to create a resource that will facilitate accurate taxonomic identifications and promote sharing of data. [ABSTRACT FROM AUTHOR]

The aphelids (phylum Aphelida) are phagotrophic parasitoids of algae and represent the most basal branch in superphylum Opisthosporidia, which contains the Microsporidia, Rozellosporidia and Aphelida. Being the closest group to traditional fungi, the aphelids should have ancestral features of both phyla. As in chytrids and other zoosporic fungi, the structure of zoospores is the most informative and important morphological feature for the phylogeny and taxonomy of aphelids. Though a general zoospore description exists for some aphelid species, their flagellar apparatus (kinetid) structure, which contains pivotal taxonomic and phylogenetic characters, has not been studied. Here we represent the kinetid structure in two genera, Aphelidium and Paraphelidium, and demonstrate independent reduction in the kinetid in each genus. The kinetid‐mitochondrion connection found in Aphelidium and Paraphelidium is rare for opisthokonts in general, but present in the most basal branches of Fungi and Opisthosporidia. We suggest, therefore, that this connection represents an ancestral character for both these phyla. [ABSTRACT FROM AUTHOR]

Periphytic ciliates play a vital role in the material cycle and energy flow of microbial food web, however, their taxonomy and biodiversity are inadequately studied given their high species richness. Two new and one little known species, viz. Derouxella lembodes gen. et sp. nov., Cyrtophoron multivacuolatum sp. nov., and Cyrtophoron apsheronica Aliev, 1991, collected from coastal waters of China, were investigated using modern methods. Derouxella gen. nov. can be recognized by having dorsoventrally flattened body, a podite, one fragmented preoral kinety, two parallel circumoral kineties, and somatic kineties progressively shortened from right to left. Morphological classification and phylogenetic analyses based on nuclear small subunit ribosomal RNA (nSSU rRNA) and mitochondrial small subunit ribosomal RNA (mtSSU rRNA) gene sequence data inferred that Derouxella gen. nov. occupies an intermediate position between Hartmannulidae and Dysteriidae. Cyrtophoron multivacuolatum sp. nov. is characterized by large body size, the numbers of somatic kineties and nematodesmal rods, and having numerous contractile vacuoles. The genus Cyrtophoron and the poorly known species C. apsheronica were redefined. Even with the addition of newly obtained nSSU rRNA and mtSSU rRNA gene sequences of Cyrtophoron, the family Chlamydodontidae was still recovered as a monophyletic group, the monophyly of Cyrtophoron was supported too. [ABSTRACT FROM AUTHOR]

We describe a new genus and species of blood‐dwelling apostome ciliate, Lynniagrapsolytica n. gen., n. sp. (Apostomatida: Colliniidae). A distinct kinety "hook" pattern on the tomite's posterior ventral face, coupled with its marine habitat and use of a decapod host, readily distinguishes this ciliate from all known colliniids. We detected the parasite in ~12% of Pachygrapsuscrassipes (Brachyura: Grapsidae) crabs in a California estuary and confirmed its presence at a Baja California rocky intertidal site. As existing methods failed to adequately stain this ciliate, we developed a new miniaturized silver carbonate impregnation staining method that produced excellent somatic and nuclear stains in all five observed cell types. A possibly unique trait is the active invagination of the tropho‐tomont's anterior to form a temporary "pseudocytopharynx," likely used for feeding. Histological examination revealed that the ciliate invaded and damaged skeletal muscle, the heart, connective tissues, and gonads. Survivorship analysis indicated that infected crabs experienced 2.6 times greater daily mortality than uninfected crabs. Laboratory and field experimental infection attempts failed, suggesting a complex life cycle with outside‐host development. Phylogenetic analysis at the 18S and COI loci confirmed the ciliate's placement in the Colliniidae. We emend the diagnosis of Family Colliniidae. [ABSTRACT FROM AUTHOR]

We have obtained a sequence of the 18S rRNA gene of the species Polychaos annulatum (Penard 1902) Smirnov et Goodkov 1998 using the isolation of a single nucleus from an amoeba cell. Attempts to amplify the 18S rRNA gene from the DNA of this species by conventional PCR were not successful, so we applied the whole genome amplification of the nuclear DNA followed by NGS sequencing. The 18S rRNA gene was found among the resulting contigs. The analysis unexpectedly shows that P. annulatum robustly groups within the family Hartmannellidae, but not Amoebidae. This finding warrants revision of the basic morphological criteria used to classify Euamoebida families and show that "proteus‐type" amoebae may belong to other families rather than Amoebidae. This makes taxonomic assignments of such species more complex and the borders between Euamoebida families more nuanced. It is getting evident that molecular data are necessary to clarify the position of species even in this most "classical" order of naked lobose amoebae. [ABSTRACT FROM AUTHOR]

The morphology of two oligotrich ciliates, Pelagostrombidium fallax (Zacharias, 1895) Krainer, 1991 and Limnostrombidium viride (Stein, 1867) Krainer, 1995, collected from a freshwater pond in northern China, was studied based on live observation and protargol staining. Currently, undescribed features in the girdle kinety in P. fallax are (a) sparsely spaced single argyrophilic basal bodies in the shoulder region and (b) a U‐shape formed below the buccal peristome. An improved diagnosis for P. fallax is supplied, based on previous and present morphological descriptions. In addition, certain ontogenetic stages of P. fallax are reported for the first time. During division, two new embryonic bodies are successively generated de novo, the first one goes to the proter, the second one to the opisthe; the new canal derives from the old canal. The morphology of L. viride is redescribed in detail; the Chinese population is highly consistent with populations in Europe. The SSU rRNA gene of P. fallax was sequenced for the first time. Phylogenetic analyses, based on SSU rRNA gene sequence data, reveal that P. fallax and L. viride cluster with Strombidium species while the result of an AU test did not reject the possibility of monophyly of the family Pelagostrombidiidae. [ABSTRACT FROM AUTHOR]

The diversity of centrohelids in inland saline waters was studied with metabarcoding for the first time. The fragment of V6–V7 regions of 18S rDNA was sequenced with newly designed primers. Obtained OTUs were identified with molecular phylogenetic analysis and comparison of the signatures in 39es9 hairpin of V7. The obtained data included some OTUs, which could be attributed to four described species, but the majority belonged to previously established or novel environmental clades. Along with some presumably marine/brackish clades and freshwater/low salinity (0–2 ppt) clades, seven presumable species demonstrating broad (from 1–2 up to 78 ppt) salinity tolerance were detected. A number of OTUs belonged to Raphidocystis contractilis, which is known from three independent findings in brackish habitats only. Thus, it was assumed that this species is stenohaline and specifically adapted to salinity 5–15 ppt. The high level of salinity tolerance was suggested for centrohelids before based on morphology, which was used to justify their cosmopolitan distribution. Later these views were criticized based on environmental sequencing, but the results of the current survey indicate, that at least some species are present at salinities from almost freshwater (1–2 ppt) to twice oceanic (78 ppt) and are presumably capable of overcoming oceanic salinity barriers for their distribution. [ABSTRACT FROM AUTHOR]

A correction to article "Molecular Phylogeny and Ontogeny of a New Ciliate Genus, Paracladotricha salina n. g., n. sp. (Ciliophora, Hypotrichia)" that was published in the 2014 issue of the periodical, is presented.

A new marine species of naked lobose amoebae Pseudoparamoeba garorimi n. sp. (Amoebozoa, Dactylopodida) isolated from intertidal marine sediments of Garorim Bay, Korea was studied with light and transmission electron microscopy. This species has a typical set of morphological characters for a genus including the shape of the locomotive form, type of subpseudopodia and the tendency to form the single long waving pseudopodium in locomotion. Furthermore, it has the same cell surface structures as were described for the type species, Pseudoparamoeba pagei: blister‐like glycostyles with hexagonal base and dome‐shaped apex; besides, cell surface bears hair‐like outgrowths. The new species described here lacks clear morphological distinctions from the two other Pseudoparamoeba species, but has considerable differences in the 18S rDNA and COX1 gene sequences. Phylogenetic analysis based on 18S rDNA placed P. garorimi n. sp. at the base of the Pseudoparamoeba clade with high PP/BS support. The level of COX1 sequence divergence was 22% between P. garorimi n. sp. and P. pagei and 25% between P. garorimi n. sp. and P. microlepis. Pseudoparamoeba species are hardly distinguishable by morphology alone, but display clear differences in 18S rDNA and COX1 gene sequences. [ABSTRACT FROM AUTHOR]

A new hypotrichous ciliate, Schmidtiella ultrahalophila gen. nov., spec. nov., was isolated from a solar saltern on the island of Sal, Cape Verde. The possession of only one short dorsal kinety clearly distinguishes S. ultrahalophila from other known hypotrichous genera and species. Further diagnostic characters include: a flexible and slender body, an average size of 85 × 15 μm in vivo; a bipartite adoral zone with two hypertrophied frontal adoral membranelles and nine to twelve ventral adoral membranelles; three frontal, one parabuccal, two frontoventral, two or three postoral ventral, and two or three frontoterminal cirri; and marginal cirral rows variable in number, usually one on each side. Ontogenetic data indicate the following: the frontal‐ventral cirri originate from six or five anlagen; the proter inherits the parental adoral zone; the frontal and ventral cirri originate from five or six anlagen; and the marginal cirral rows and the dorsal kinety tend to originate intrakinetally. Additional marginal rows are rarely derived from de novo anlagen. Based on its morphology, morphogenesis and its SSU rRNA phylogenetic placement, the new species should be assigned to the order Sporadotrichida Fauré‐Fremiet, 1961. Due to low taxon sampling, however, its exact position in this order remains enigmatic. [ABSTRACT FROM AUTHOR]

Chorthippus loratus collected in Krasnodar Territory in 2017 was infected at 15% rate with a microsporidium possessing ovocylindrical binucleate spores, 2.6 × 1.2 μm in size. SSU RNA gene typing (Genbank accession # MH396491) showed its allocation to the genus Liebermannia. Degenerate primers based upon largest subunit RNA polymerase II (RPB1) sequences of closest relatives allowed amplifying the respective gene fragment of Liebermannia sp. (# MH396492). The present finding indicates worldwide distribution of the Liebermannia genus and parasitism in hosts with nonoverlapping geographic ranges (representing Neotropical versus Palearctic fauna), while previous observations were restricted to Acridoidea endemic for South America. [ABSTRACT FROM AUTHOR]

Abstract: Two amoeboid organisms of the genera Sappinia Dangeard, 1896 and Rosculus Hawes, 1963 were identified in a sample containing king penguin guano. This sample, collected in the Subantarctic, enlarges the list of fecal habitats known for the presence of coprophilic amoebae. The two organisms were co‐isolated and subcultured for over 6 mo, with continuous efforts being invested to separate each one from the mixed culture. In the mixed culture, Rosculus cells were fast growing, tolerated changes in culturing conditions, formed cysts, and evidently were attracted by Sappinia trophozoites. The separation of the Rosculus strain was accomplished, whereas the Sappinia strain remained intermixed with inseparable Rosculus cells. Sappinia cell populations were sensitive to changes in culturing conditions; they improved with reduction of Rosculus cells in the mixed culture. Thick‐walled cysts, reportedly formed by Sappinia species, were not seen. The ultrastructure of both organisms was congruent with the currently accepted generic characteristics; however, some details were remarkable at the species level. Combined with the results of phylogenetic analyses, our findings indicate that the ultrastructure of the glycocalyx and the presence/absence of the Golgi apparatus in differential diagnoses of Sappinia species require a critical re‐evaluation. [ABSTRACT FROM AUTHOR]

Abstract: The opisthokonts constitute a eukaryotic supergroup divided into two main clades: the holozoans, which include animals and their unicellular relatives, and the holomycotans, which include fungi, opisthosporidians, and nucleariids. Nucleariids are phagotrophic filose amoebae that phenotypically resemble more their distant holozoan cousins than their holomycotan phylogenetic relatives. Despite their evolutionary interest, the diversity and internal phylogenetic relationships within the nucleariids remain poorly studied. Here, we formally describe and characterize by molecular phylogeny and microscopy observations Parvularia atlantis gen. et sp. nov. (formerly Nuclearia sp. ATCC 50694), and compare its features with those of other nucleariid genera. Parvularia is an amoebal genus characterized by radiating knobbed and branching filopodia. It exhibits prominent vacuoles observable under light microscopy, a cyst‐like stage, and completely lacks cilia. P. atlantis possesses one or two nuclei with a central nucleolus, and mitochondria with flat or discoid cristae. These morphological features, although typical of nucleariids, represent a combination of characters different to those of any other described Nuclearia species. Likewise, 18S rRNA‐based phylogenetic analyses show that P. atlantis represents a distinct lineage within the nucleariids. [ABSTRACT FROM AUTHOR]

Abstract: The morphology and molecular phylogeny of a soil hypotrich ciliate, Pseudourostyla guizhouensis sp. nov., collected from southern China, were investigated. Pseudourostyla guizhouensis sp. nov. has an elongate elliptical body measuring 180–310 × 65–85 μm in vivo; invariably two right and three or four left marginal rows; six or seven dorsal kineties; adoral zone consisting of 57–70 membranelles; 12–16 frontal cirri, one buccal cirrus, 13–20 midventral pairs, two frontoterminal cirri, two pretransverse cirri, and five to seven transverse cirri. Morphogenesis during physiological regeneration indicates that the marginal rows of each side originate from a common anlage that differentiates into several rows. Molecular phylogenetic analysis based on SSU rDNA sequence data reveals that P. guizhouensis sp. nov. clusters with the type species P. cristata (Jerka‐Dziadosz, 1964) Borror, 1972 and that the genus Pseudourostyla is monophyletic. The morphological characters of another soil hypotrich ciliate, Hemicycliostyla franzi (Foissner, 1987) Paiva et al., 2012, are also described based on a Chinese (Guizhou) population. [ABSTRACT FROM AUTHOR]

Aphelids are a diverse group of intracellular parasitoids of algae and diatoms, and are sister to true fungi. Included in four genera, the 14 described species utilize phagocytosis as their mode of nutrition, and the life cycles of these taxa are remarkably similar. However, their putative specificity of host, morphological and ultrastructural features, and genetic divergence have been considered in taxon delineation. Here, we examine the host specificity, morphology, ultrastructure, and molecular 18S gene sequence of a new species in Aphelida, Aphelidium desmodesmi sp. nov. This taxon is in a well-supported clade with two other species of Aphelidium, and this lineage is sister to Amoeboaphelidium and Paraphelidium. Of interest, the mitochondrial structure of Aph. desmodesmi is more like that of Paraphelidium than that of Aphelidium aff. melosirae, the only other species of Aphelidium to have been examined ultrastructurally. This research examines and expands our understanding of host range, morphological diversity, and genetic divergence of the aphelids. [ABSTRACT FROM AUTHOR]

A new soil ciliate, Pseudonotohymena antarctica n. g., n. sp., from King George Island, Antarctica, is described based on live observation, protargol impregnation, and its 18S rRNA gene. The new genus Pseudonotohymena is morphologically similar to the genus Notohymena Blatterer and Foissner in the following characteristics: 18 fronto-ventral-transverse cirri, a flexible body, undulating membranes, dorsomarginal kineties, and the number of cirri in the marginal rows. However, Pseudonotohymena differs from Notohymena particularly in the dorsal ciliature, that is, in possessing a nonfragmented dorsal kinety (vs. fragmented). In addition, the molecular phylogenetic relationship of the new species differs from that of Notohymena species. On the basis of the morphological features, the genetic data, and morphogenesis, we establish P. antarctica n. g., n. sp. In addition, the cyst morphology of this species is described. [ABSTRACT FROM AUTHOR]

The ciliate genus Protocruzia is a highly confused group, which was formerly placed in the class Heterotrichea or Karyorelictea, and is according to the most recent system tentatively assigned to the class Spirotrichea. In the present study, the morphology, ciliary pattern, and molecular phylogeny of two poorly known species, Protocruzia tuzeti Villeneuve-Brachon, 1940, and Protocruzia granulosa Kahl, 1933, isolated from coastal waters of China, were investigated. Protocruzia tuzeti differs from its congeners mainly in possessing 6 adoral membranelles, 8-11 somatic kineties, and postoral dikinetids. Protocruzia granulosa is characterized by its extremely slender body, three postoral kineties, and 13 or 14 somatic kineties. The morphogenesis of P. granulosa is similar to that of P. tuzeti, especially in the parakinetal mode of stomatogenesis and the reorganization of the parental paroral membrane; however, more than one somatic kinety joins in the formation of the oral primordium in P. granulosa. Phylogenetic analyses based on small subunit ribosomal RNA gene revealed that six Protocruzia species form a fully supported clade that does not belong to any ciliate class; therefore, our data support the establishment of the class Protocruziea Gao et al. ( Sci. Rep., 6, 2016, 24874). [ABSTRACT FROM AUTHOR]

A new freshwater species of naked lobose amoebae Korotnevella venosa n. sp. isolated from freshwater pond in St. Petersburg, Russia was studied with light and transmission electron microscopy. Basket scales of this species have six vertical columns supporting perforated rim. The latter has tongue-like broadening with membranous region. Vertical columns bifurcate at both ends so that neighboring columns are connected by their bifurcations forming combined structure. Basket scales of K. venosa are similar to those of Korotnevella hemistylolepis in having six full-length vertical columns and perforated rim. At the same time, they are different in having tongue-like broadening of perforated rim with membranous region and absence of six half-length columns and an intermediate crosspiece. Phylogenetic trees based on 18S rDNA gene placed K. venosa either at the base of the whole Korotnevella clade, next to K. hemistylolepis, or as a sister to the clade comprising Korotnevella species with latticework basket in large scales. [ABSTRACT FROM AUTHOR]

The microsporidium parasitizing Inland Bearded Dragons Pogona vitticeps, and developing primarily in macrophages within foci of granulomatous inflammation of different organs, is described as a new species Encephalitozoon pogonae. Establishing the new species was based on sequencing the ITS-SSUrDNA region of the ribosomal gene and consequent SSUrDNA-inferred phylogenetic analyses, as well as on comparison of pathogenesis, host specificity, and ultrastructure among Encephalitozoon species and isolates. The new species is closely related to E. lacertae and E. cuniculi. Analysis of the literature suggests that this microsporidium has been reported previously as an unidentified microsporidian species or isolate of E. cuniculi and may represent a common infection in bearded dragons. All stages of E. pogonae develop in parasitophorous vacuoles. Uninucleate spores on methanol-fixed smears measured 2.1 x 1.1 µm, range 1.7-2.6 x 0.9-1.7 µm; on ultrathin sections spores measured 0.8-1.1 x 1.8-2.2 µm. Ultrastructural study revealed 3-6 polar filament coils, a mushroom-shaped polar disk, and a polar sac embracing half of the volume occupied by the lamellar polaroplast. In activated spores, polar filament everted eccentrically. The overall morphology and intracellular development of E. pogonae were similar to other Encepahalitozoon spp. We also review the existing data on microsporidia infecting reptiles. [ABSTRACT FROM AUTHOR]

Two marine urostylid ciliates, Caudiholosticha marina sp. nov. and Nothoholosticha flava sp. nov., isolated from intertidal sediment in the Yellow Sea, are investigated using morphological and small subunit rDNA phylogenetic analyses. Caudiholosticha marina is 210-310 µm x 40-55 µm in vivo, and has 10-20 macronuclear nodules, 23-37 midventral cirral pairs extending to 5-8 transverse cirri, and two caudal cirri. It differs from congeners by its marine habitat, larger size, macronuclear arrangement pattern and high number of midventral pairs. Molecular phylogenetic analyses indicate a polyphyly of Caudiholosticha. Nothoholosticha flava is yellow to brownish and 240-320 µm x 40-60 µm sized, and has a bipartite adoral zone, six frontal cirri in atypical bicorona, usually four frontoterminal, one buccal and 5-7 transverse cirri and 28-54 midventral pairs. Phylogenetic analyses allocate N. flava as sister of N. fasciola, type of the genus. The two Nothoholosticha species differ distinctly by the presence/absence of frontoterminal cirri, a feature often used to define genera in the Hypotrichia. However, the SSU rDNA sequence similarity between these two species is 99.3%, which weakens the justification for separating the new isolate at genus level. The taxonomic significance of frontoterminal cirri is discussed based on morphological and molecular data. [ABSTRACT FROM AUTHOR]

Two colepid ciliates, Levicoleps taehwae nov. spec. and L. biwae jejuensis nov. subspec., were collected from the brackish water of the Taehwa River and a small freshwater pond in Jeju Island, South Korea, respectively. Their living morphology, infraciliature, and small subunit (SSU) rRNA gene sequences were determined using standard methods. Barrel-shaped L taehwae nov. spec. is a small ciliate with an average size of 45 9 25 lm in vivo, about 15 ciliary rows each composed of 12 monokinetids and two perioral dikinetids, and two 20 µm-long caudal cilia. The sequence length and GC content of the SSU rRNA gene are 1,669 bp, 44.5%. This novel species is similar in body size to Coleps hirtus, and has six armor tiers and hirtus-type tier plates, and the same number of ciliary rows as C. hirtus; however, it can be distinguished from the latter by the absence of armor spines and its sequence similarity of SSU rRNA gene is about 92.8% which indicates that it is a distinct form. Levicoleps biwae jejuensis nov. subspec., is a medium colepid ciliate which has a barrel-shaped body, about 22 somatic kineties and 16 transverse ciliary rows, three mini adoral organelles, and four 15 µm-long caudal cilia. The sequence length and GC content of the SSU rRNA gene are 1,666 bp and 44.4%. [ABSTRACT FROM AUTHOR]

Two populations of Epistylis chlorelligerum Shen 1980, a colonial limnetic peritrich ciliate, were collected from different locations in China: E. chlorelligerum 1 from West Lake, Hangzhou; E. chlorelligerum 2 from East Lake, Wuhan. The morphology, infraciliature and SSU rRNA gene sequence of the two populations were investigated based on living and protargol-stained specimens. Although both populations are consistent with previous descriptions of protargol-stained specimens of this species, some differences in the morphology in vivo were observed. The two populations had identical SSU rRNA gene sequences. A second species, Epistylis chrysemydis Bishop and Jahn 1941, was also collected from East Lake, Wuhan, and was investigated for its morphology, infraciliature and SSU rRNA gene sequence. Phylogenetic analyses based on SSU rRNA gene sequence data indicate that the two populations of E. chlorelligerum are nested within the Epistylididae clade near E. wenrichi and E. urceolata. Epistylis chrysemydis is sister to the group comprising E. chlorelligerum, E. wenrichi, and E. urceolata. [ABSTRACT FROM AUTHOR]

The small and large nuclear subunit molecular phylogeny of the genus Prorocentrum demonstrated that the species are dichotomized into two clades. These two clades were significantly different (one-factor ANOVA, p < 0.01) with patterns compatible for both small and large subunit Bayesian phylogenetic trees, and for a larger taxon sampled dinoflagellate phylogeny. Evaluation of the molecular divergence levels showed that intraspecies genetic variations were significantly low ( t-test, p < 0.05), than those for interspecies variations (> 2.9% and > 26.8% dissimilarity in the small and large subunit [D1/D2], respectively). Based on the calculated molecular divergence, the genus comprises two genetically distinct groups that should be considered as two separate genera, thereby setting the pace for major systematic changes for the genus Prorocentrum sensu Dodge. Moreover, the information presented in this study would be useful for improving species identification, detection of novel clades from environmental samples. [ABSTRACT FROM AUTHOR]

This study investigated the morphology and molecular characteristics of three interesting free-living cyrtophorid ciliates, including two new species, isolated from China: Chilodonella parauncinata sp. n. can be identified by its elongated body shape, with a sharp protrusion in the left anterior part, cell size ca. 60 × 25 μm in vivo, five right and 6-7 left kineties with kinetosomes densely arranged, and a curved cyrtos. Chlamydonella irregularis sp. n. differs from its congeners by the oval body shape, cell size 50-60 × 25-40 μm in vivo, irregular shape of macronucleus, 30-40 club-shaped ventral protuberances, and 17 somatic kineties. Two isolates of Chlamydonella derouxi Song, 2003, collected from an intertidal area in Shandong and a mangrove wetland in Guangdong respectively, correspond well with two previous descriptions, but differ in comprising more basal bodies in left and right equatorial fragments and in having more finger-like protuberances on the ventral side. Phylogenetic analyses based on the small subunit r RNA gene sequences showed that C. parauncinata sp. n. clustered with Chilodonella uncinata, but was a well-outlined species of the genus, and C. irregularis sp. n. and C. derouxi grouped in the family Lynchellidae with their congeners to form the monophyletic genus Chlamydonella. [ABSTRACT FROM AUTHOR]

Monothalamous (single-chambered) foraminifera have long been considered as the 'poor cousins' of multichambered species, which calcareous and agglutinated tests dominate in the fossil record. This view is currently changing with environmental DNA surveys showing that the monothalamids may be as diverse as hard-shelled foraminifera. Yet, the majority of numerous molecular lineages revealed by e DNA studies remain anonymous. Here, we describe a new monothalamous species and genus isolated from the sample of sea grass collected in Gulf of Eilat (Red Sea). This new species, named Leannia veloxifera, is characterized by a tiny ovoid theca (about 50-100 μm) composed of thin organic wall, with two opposite apertures. The examined individuals are multinucleated and show very active reticulopodial movement. Phylogenetic analyses of SSU r DNA, actin, and beta-tubulin (ß-tubulin) show that the species represents a novel lineage branching separately from other monothalamous foraminifera. Interestingly, the SSU r DNA sequence of the new species is very similar to an environmental foraminiferal sequence from Bahamas, suggesting that the novel lineage may represent a group of shallow-water tropical allogromiids, poorly studied until now. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The Psilotrichidae are a family of middle-sized hypotrichs with unique morphological and ontogenetic features (e.g. the oral primordium develops in a deep pouch) that, however, did not provide a definite phylogenetic signal. Thus, we studied the 18S rRNA gene of Urospinula succisa (Müller 1786) Esteban et al., 2001 as well as the morphology and ontogenesis of Psilotrichides hawaiiensis, a new genus and species from an ephemeral swamp on Oahu Island, Hawaii. The molecular data classify the psilotrichids into the oxytrichids but without clear branching position. A brief revision, using the structure of the oral apparatus, the location of the contractile vacuole, and three ontogenetic features, showed four distinct genera: Psilotricha Stein, 1859; Urospinula Corliss, 1960; Hemiholosticha Gelei, 1954; and Psilotrichides nov. gen., which differs from the confamilials mainly by the obliquely oriented buccal cavity and the shape of the undulating membranes as well as by a distinct ridge along the right buccal margin. The pyriform species, P. hawaiiensis, is about 65 × 45 μm in size and is easily recognized by the table tennis racket-shaped appearance due to the elongated last cirrus of the left marginal row. Refined diagnoses are provided for the family Psilotrichidae Bütschli, 1889 and the genera contained. [ABSTRACT FROM AUTHOR]

We discovered a new haptorian ciliate, Chaenea mirabilis sp. n., in brackish water collected near the town of Busan, Korea. Its morphology was studied using standard taxonomical methods and its phylogenetic relationships were assessed by phylogenetic analysis of the 18S rRNA gene. Chaenea mirabilis is distinguished from all congeners by the combination of the following traits: (i) a narrowly bursiform to flask-shaped, 60-100 μm long body; (ii) 11-21 doughnut-shaped or sometimes horseshoe-shaped macronuclear nodules; (iii) two types of extrusomes: type I is rod-shaped and 6-8 μm long, while type II is narrowly to broadly teardrop-shaped and only 1.5-2 μm long; (iv) highly refractive special granules tightly arranged between the first and second brush row, forming a conspicuous bulge; and (v) 12-13 somatic kineties. In the 18S rRNA gene phylogeny, C. mirabilis clustered with full support with other congeners. However, there was no statistical support for classification of Chaenea into the families Fuscheriidae, Acropisthiidae, or Trachelophyllidae, but a sister relationship with the Lacrymariidae could not be excluded. Therefore, we establish a new family, Chaeneidae, within the order Lacrymariida. This affiliation is strongly corroborated by the distinctly subapical dorsal brush bearing cilium-like bristles. [ABSTRACT FROM AUTHOR]

A terrestrial oxytrichid ciliate Paraparentocirrus sibillinensis n. gen., n. sp., which was found in soil samples of a beech forest stand within the National Park of Sibillini Mountains, Italy, was investigated using live observation and protargol impregnation. The morphology of interphase, morphogenesis, and molecular phylogeny inferred from SSU r DNA sequences of this ciliate were studied. Paraparentocirrus n. gen., is mainly characterized by a semirigid body, an undulating membrane in the Oxytricha pattern, six fronto-ventral (FV) rows, the absence of transverse cirri, one right and one left row of marginal cirri, four dorsal kineties, two dorsomarginal rows, and caudal cirri at the end of dorsal kinety 4. During morphogenesis, oral primordia develop through the proliferation of basal bodies from some cirri of FV rows 4 and 5, and FV row 6 takes part in the anlagen formation of the proter. The dorsal morphogenesis was typical of oxytrichids, with simple fragmentation of dorsal kinety 3, and the dorsomarginal rows developed from the right marginal row. Phylogenetic analyses based on the SSU r DNA sequences support the classification of this new genus in the stylonychines. [ABSTRACT FROM AUTHOR]

Euplotes woodruffi Gaw 1939 is a striking ciliate species commonly used in many fields of protistology. Euplotes parawoodruffi Song and Bradbury 1997 is separated from E. woodruffi by several morphological differences (e.g. the absence of pre-oral pouch) and in particular the brackish habitat (vs. freshwater). However, recent molecular data dispute the separation of E. woodruffi into two species. Based on a brackish isolate from the southeast of China, we investigated the morphology, molecular phylogeny, and adaptation of E. woodruffi using living observation, protargol impregnation, gene sequencing, and cultivation experiments. The morphological variability present in our isolate encompasses the previous descriptions of E. woodruffi and E. parawoodruffi. The pre-oral pouch, which occurs in living cells of freshwater isolates, is also recognizable in the brackish specimens. Laboratory experiments suggested that the brackish isolate could acclimatize and reproduce in both brackish and fresh water. The molecular analyses using 13 available small subunit ( SSU) rRNA gene sequences showed that the minimum pairwise sequence similarity is as high as 99.2% and nine sequences from both brackish and freshwater isolates are even 100% matched. Therefore, we conclude that E. parawoodruffi is a junior synonym of E. woodruffi. [ABSTRACT FROM AUTHOR]

Although archigregarines are poorly understood intestinal parasites of marine invertebrates, they are critical for understanding the earliest stages in the evolution of the Apicomplexa. Previous studies suggest that archigregarines are a paraphyletic stem group from which other lineages of gregarines, and possibly all other groups of apicomplexans, evolved. However, substantiating this inference is difficult because molecular phylogenetic data from archigregarines, in particular, and other gregarines, in general, are severely limited. In an attempt to help fill gaps in our knowledge of archigregarine diversity and phylogeny, we set out to discover and characterize novel lineages of archigregarines with high-resolution light and scanning electron microscopy and analyses of small subunit ( SSU) rDNA sequences derived from single-cell ( SC) PCR techniques. Here, we describe two novel species of Selenidium, namely Selenidium idanthyrsae n. sp. and S. boccardiellae n. sp., and demonstrate the surface morphology and molecular phylogenetic position of the previously reported species S. cf. mesnili. We also describe a novel genus of archigregarine, Veloxidium leptosynaptae n. gen., n. sp., which branches with an environmental sequence and, together, forms the nearest sister lineage to a diverse clade of marine eugregarines (i.e. lecudinids and urosporids). This molecular phylogenetic result is consistent with the hypothesis that archigregarines are deeply paraphyletic within apicomplexans, and suggests that convergent evolution played an important role in shaping the diversity of eugregarine trophozoites. [ABSTRACT FROM AUTHOR]

Persistent difficulties in resolving clear lineages in diverging populations of prokaryotes or unicellular eukaryotes (protistan polyphyletic groups) are challenging the classical species concept. Although multiple integrated approaches would render holistic taxonomies, most phylogenetic studies are still based on single-gene or morphological traits. Such methodologies conceal natural lineages, which are considered 'cryptic.' The concept of species is considered artificial and inadequate to define natural populations. Social organisms display differential behaviors toward kin than to nonrelated individuals. In 'social' microbes, kin discrimination has been used to help resolve crypticity. Aggregative behavior could be explored in a nonsocial protist to define phylogenetic varieties that are considered 'cryptic.' Two Entamoeba invadens strains, IP-1 and VK-1:NS are considered close populations of the same 'species.' This study demonstrates that IP-1 and VK-1:NS trophozoites aggregate only with alike members and discriminate members of different strains based on behavioral and chemical signals. Combined morphological, behavioral/chemical, and ecological studies could improve Archamoebae phylogenies and define cryptic varieties. Evolutionary processes in which selection acted continuously and cumulatively on ancestors of Entamoeba populations gave rise to chemical and behavioral signals that allowed individuals to discriminate nonpopulation members and, gradually, to the emergence of new lineages; alternative views that claim a 'Designer' or 'Creator' as responsible for protistan diversity are unfounded. [ABSTRACT FROM AUTHOR]

ABSTRACT. The morphology, infraciliature, and molecular phylogeny of Pseudodiophrys nigricans n. g., n. sp., and Paradiophrys zhangi n. sp., isolated from a sandy beach near Qingdao, China, were investigated. Pseudodiophrys is characterized by the Diophrys-like ciliature pattern, but having only a single, reduced undulating membrane. Pseudodiophrys nigricans, the type species by monotypy, is described from live and silver-impregnated specimens. Paradiophrys zhangi is similar to the type species Paradiophrys irmgard but can be recognized by its border body and the number (7 vs. 8-10) and arrangement (in rows vs. sparsely distributed) of the frontoventral cirri. Small subunit (SSU) rRNA gene sequence data support the validity of both species. Phylogenetic analyses based on the SSU rRNA gene sequence data currently available for uronychiids and other related taxa indicate that P. nigricans is most closely related to Diophrys scutum and Diophrys apoligothrix, while P. zhangi clusters most closely with Apodiophrys ovalis within a clade that also includes two other Paradiophrys species. [ABSTRACT FROM AUTHOR]

The urostylid genus Metaurostylopsis Song et al., 2001 was considered to be a well-outlined taxon. Nevertheless, recent evidence, including morphological, ontogenetic, and molecular information, have consistently revealed conflicts among congeners, regarding their systematic relationships, ciliature patterns, and origins of ciliary organelles. In the present work, the morphogenetic and morphogenetic features were re-checked and compared, and the phylogeny of nominal species was analysed based on information inferred from the small subunit ribosomal RNA (SS rRNA) gene sequence. In addition, the binary divisional process in a new isolate of Metaurostylopsis struederkypkeae Shao et al., 2008 is described. All results obtained reveal that the genus is a polyphyletic assemblage whose nominal congeners fall into three clades within the core Urostylida, based on SS rRNA gene sequences. These three clades not match the groups inferred from morphological/morphogenetical evidences. Some conflicting data from molecular and ontogenetic studies also indicate that single-gene information might not be consistently reliable in detecting the phylogenetic relationships among closely related groups and comprehensive multi-gene analyses are necessary to give a more exact evaluation for this divergent assemblage. According to our new understandings, five forms are confirmed to be true Metaurostylopsis. The morphotype Metaurostylopsis sinica Shao et al., 2008 should be excluded from the genus and represents a distinct type, and, thus, a new genus Apourostylopsis n. g. with it as the type specie, i.e. Apourostylopsis sinica (Shao et al., 2008) n. comb. [ABSTRACT FROM AUTHOR]

We discovered a free-living peritrich ciliate with outstanding features in the River Rhine. Its morphology and 18S rRNA gene sequence were studied with standard methods. Apocarchesium arndti n. sp. has several peculiarities. (i) There are ordinary zooids, macrozooids, and microzooids, which form a hemispherical rosette on a discoidal base, the stalk dish, locking the ∼18 μm wide and up to 2 mm long, spirally contracting colony stalk. (ii) The stalk myoneme is connected only to the microzooids. (iii) A rosette contains up to 50 zooids not connected to each other but individually attached to the stalk dish with the scopula. (iv) The ordinary zooids are epistylidid, trumpet-shaped (∼6:1 length:width), about 180 × 30 μm in size, and have an ellipsoidal macronucleus subapically between oral cavity and dorsal side. (v) The myoneme system of the zooids, which can contract individually, forms a tube-like structure in the narrow posterior half of the cell. (vi) The silverline pattern belongs to the transverse-striate type. (vii) The oral apparatus is of usual structure, with kinety 1 of peniculus 3 distinctly shortened proximally. (viii) The 18S rRNA places A. arndti n. sp. as a distinct lineage near Vorticella and Carchesium. These data are used to provide an improved diagnosis of the genus Apocarchesium. Features (i)–(iii) and the molecular data indicate that Apocarchesium could be the type genus of a new peritrich family. [ABSTRACT FROM AUTHOR]

Spumochlamys perforata n. sp. and Spumochlamys bryora n. sp. were isolated and described from dry epiphytic moss. The morphology and ultrastructure of both species clearly demonstrate that they belong to the genus Spumochlamys (family Microchlamyiidae). They differ from its only described member, Spumochlamys iliensis (as well as from species of Microchlamys), in the relief of the dorsal surface of the test, revealed by scanning electron microscopy, which can represent a good characteristic for species identification. They also differ in the structure of the dorsal part of the test wall (especially S. perforata). Small subunit ribosomal DNA-based molecular phylogenetic analyses show that Spumochlamys is a deeply branching lineage of the Arcellinida, without any close affinities. Actin gene sequence analysis places this genus within the Tubulinea, close to two other arcellinid lineages but without forming a monophyletic group with them. These data together strongly suggest that the lack of resolution in the arcellinid molecular phylogenies is due to serious undersampling of taxa, a limited number of sequence data, and high divergence rates in most of the species. [ABSTRACT FROM AUTHOR]

The trophozoites of two novel archigregarines, Selenidium pisinnus n. sp. and Filipodium phascolosomae n. sp., were described from the sipunculid Phascolosoma agassizii. The trophozoites of S. pisinnus n. sp. were relatively small (64–100 μm long and 9–25 μm wide), had rounded ends, and had about 21 epicytic folds per side. The trophozoites of F. phascolosomae n. sp. were highly irregular in shape and possessed hair-like surface projections. The trophozoites of this species were 85–142 μm long and 40–72 μm wide and possessed a distinct longitudinal ridge that extended from the mucron to the posterior end of the cell. In addition to the small subunit (SSU) rDNA sequences of these two species, we also characterized the surface morphology and SSU rDNA sequence of Selenidium orientale, isolated from the sipunculid Themiste pyroides. Molecular phylogenetic analyses demonstrated that S. pisinnus n. sp. and S. orientale formed a strongly supported clade within other Selenidium and archigregarine-like environmental sequences. Filipodium phascolosomae n. sp. formed the nearest sister lineage to the dynamic, tape-like gregarine Selenidium vivax. Overall, these data enabled us to reassess the molecular systematics of archigregarines within sipunculid hosts and make the following revisions: (1) Filipodium was transferred from the Lecudinidae (eugregarines) to the Selenidiidae (archigregarines), and (2) Platyproteum n. g. was established for Platyproteum vivax n. comb. (ex. S. vivax) in order to account for the highly divergent morphological features and better resolved phylogenetic position of this lineage. [ABSTRACT FROM AUTHOR]

We describe a new microsporidian species Binucleata daphniae, n. g., n. sp., that infects the integument cells lining the hemocoele cavity of the carapace and the postabdomen of the cladoceran Daphnia magna Straus. Infected cells filled with spores accumulate as large clusters in the carapace cavity and heavily infected hosts are detected by their opaque appearance. Despite the parasite's presence, infected Daphnia grow and molt, but have a reduced fecundity. During the parasite's life cycle, chain-like meronts with isolated nuclei are formed, giving rise to binucleate presporonts, the most frequently observed, characteristic developmental stage. In sporogony, the nuclei of the presporont separate, divide, and eight spores enclosed in a thin-walled sporophorous vesicle are formed. Spores are 4.9 × 2.5 μm in size (fresh) and have an anisofilar polar filament with eight coils. DNA sequence analysis places B. daphniae in a clade of microsporidians that parasitize crustaceans and mosquitoes and have assumed complex life cycles. Binucleata daphniae, however, has a simple and direct life cycle and can be transferred to naïve hosts and maintained as persistent infections in populations of its host D. magna. We propose that B. daphniae has simplified its life cycle by losing its secondary host, rendering it unique in this clade. [ABSTRACT FROM AUTHOR]

A comprehensive molecular analysis of the phylogenetic relationships within the Heterotrichea including all described families is still lacking. For this reason, the complete nuclear small subunit (SSU) rDNA was sequenced from further representatives of the Blepharismidae and the Stentoridae. In addition, the SSU rDNA of a new, undescribed species of the genus Condylostomides (Condylostomatidae) was sequenced. The detailed phylogenetic analyses revealed a consistent branching pattern: while the terminal branches are generally well resolved, the basal relationships remain unsolved. Moreover, the data allow some conclusions about the macronuclear evolution within the genera Blepharisma, Stentor, and Spirostomum suggesting that a single, compact macronucleus represents the ancestral state. [ABSTRACT FROM AUTHOR]

The gene encoding 18S small subunit ribosomal RNA (ssu rRNA) was sequenced in the sessiline peritrichs Opisthonecta minima and Opisthonecta matiensis, whose free-swimming, paedomorphic trophonts resemble telotrochs. Using these new sequences, phylogenetic trees were constructed with four different methods to test a previously published association between Opisthonecta henneguyi and members of the families Vorticellidae and Astylozoidae. All trees had similar topologies, with O. minima, O. henneguyi, Vorticella microstoma, and Astylozoon enriquesi forming a well-supported, certainly monophyletic clade. On the basis of genetic evidence, genera of the families Opisthonectidae and Astylozoidae are assigned to the family Vorticellidae, which already includes some species with free-swimming morphotypes. The ssu rRNA sequence of O. matiensis places it in the family Epistylididae; its taxonomic revision will be left to another group of authors. A close association of Ophrydium versatile with members of the family Vorticellidae was confirmed, casting doubt on the validity of the family Ophrydiidae. Epistylis galea, Campanella umbellaria, and Opercularia microdiscum are confirmed as comprising an extremely distinct, monophyletic, but morphologically heterogeneous clade that is basal to other clades of sessiline peritrichs. [ABSTRACT FROM AUTHOR]

To determine the phylogenetic position of Stentor within the Class Heterotrichea, the complete small subunit rRNA genes of three Stentor species, namely Stentor polymorphus, Stentor coeruleus, and Stentor roeseli, were sequenced and used to construct phylogenetic trees using the maximum parsimony, neighbor joining, and Bayesian analysis. With all phylogenetic methods, the genus Stentor was monophyletic, with S. roeseli branching basally. [ABSTRACT FROM AUTHOR]

The gene coding for 18S small subunit ribosomal RNA (ssu rRNA) was sequenced in seven free-living, marine species of the sessiline peritrich genus Zoothamnium. These were Zoothamnium niveum, Zoothamnium alternans, Zoothamnium pelagicum, and four unidentified species. The ssu rRNA gene also was sequenced in Vorticella convallaria, Vorticella microstoma, and in an unidentified, freshwater species of Vorticella. Phylogenetic trees were constructed using these new sequences to test a previously published phylogenetic association between Zoothamnium arbuscula, currently in the family Zoothamniidae, and peritrichs in the family Vorticellidae. Trees constructed by means of neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian inference methods all had similar topologies. The seven new sequences of Zoothamnium species grouped into three well-supported clades, each of which contained a diversity of morphological types. The three clades formed a poorly supported, larger clade that was deeply divergent from Z. arbuscula, which remained more closely associated with vorticellid peritrichs. It is apparent that Zoothamnium is a richly diverse genus and that a much more intensive investigation, involving both morphological and molecular data and a wider selection of species, will be necessary to resolve its phylogeny. A greater amount of molecular diversity than is predicted by morphological data exists within all major clades of sessiline peritrichs that have been included in molecular phylogenies, indicating that characteristics of stalk and peristomial structure traditionally used to differentiate taxa at the generic level and above may not be uniformly reliable. [ABSTRACT FROM AUTHOR]

A new microsporidian Trachipleistophora extenrec n. sp. was isolated from a muscle lesion of the streaked tenrec Hemicentetes semispinosus Cuvier, 1798 (Mammalia, Tenrecidae), an insectivore endemic to Madagascar. The spores isolated from the tenrec were infectious to SCID) mice by intramuscular injection. Material obtained from muscular lesions in mice was used for the parasite description. All developmental stages of the microsporidian were covered by a dense coat, which during sporogony changed into the sporophorous vesicle wall. Eight, 16, 32, or more spores were formed inside the sporophorous vesicle as the result of the division by plasmotomy and sequential fission of a multinucleate sporogonial plasmodium. Spores were ovoid, 4.7 × 2.8 μm in size, had a large posterior vacuole, and had an isofilar polar tube with 15–16 coils. Although the fine structure and the developmental pattern of the organism were in some respects similar to the genus Vavraia, molecular phylogeny based on the gene sequences of the small subunit rRNA and RNA polymerase subunit II indicated that the organism belongs to the genus Trachipleistophora. The diagnostic characters of the genera Trachipleistophora and Vavraia are discussed as well as the discrepancies between the phylogenies of these two microsporidian genera based on morphology and molecules. [ABSTRACT FROM AUTHOR]

Based on morphological characters, peritrich ciliates (Class Olygohymenophorea, Subclass Peritrichia) have been subdivided into the Orders Sessilida and Mobilida. Molecular phylogenetic studies on peritrichs have been restricted to members of the Order Sessilida. In order to shed more light into the evolutionary relationships within peritrichs, the complete small subunit rRNA (SSU rRNA) sequences of four mobilid species, Trichodina nobilis, Trichodina heterodentata, Trichodina reticulata, and Trichodinella myakkae were used to construct phylogenetic trees using maximum parsimony, neighbor joining, and Bayesian analyses. Whatever phylogenetic method used, the peritrichs did not constitute a monophyletic group: mobilid and sessilid species did not cluster together. Similarity in morphology but difference in molecular data led us to suggest that the oral structures of peritrichs are the result of evolutionary convergence. In addition, Trichodina reticulata, a Trichodina species with granules in the center of the adhesive disc, branched separately from its congeners, Trichodina nobilis and Trichodina heterodentata, trichodinids without such granules. This indicates that granules in the adhesive disc might be a phylogenetic character of high importance within the Family Trichodinidae. [ABSTRACT FROM AUTHOR]

A new species of Rhytidocystis (Apicomplexa) is characterized from North American waters of the Atlantic Ocean using electron microscopy and phylogenetic analyses of small subunit (SSU) rDNA sequences. Rhytidocystis polygordiae n. sp. is a parasite of the polychaete Polygordius sp. and becomes the fourth described species within this genus. The trophozoites of R. polygordiae were relatively small oblong cells ( L=35–55 μm; W=20–25 μm) and distinctive in possessing subterminal indentations at both ends of the cell. The surface of the trophozoites had six to eight longitudinal series of small transverse folds and several micropores arranged in short linear rows. The trophozoites of R. polygordiae were positioned beneath the brush border of the intestinal epithelium but appeared to reside between the epithelial cells within the extracellular matrix rather than within the cells. The trophozoites possessed a uniform distribution of paraglycogen granules, putative apicoplasts, mitochondria with tubular cristae, and a centrally positioned nucleus. The trophozoites were non-motile and lacked a mucron and an apical complex. Intracellular sporozoites of R. polygordiae had a conoid, a few rhoptries, micronemes, dense granules, and a posteriorly positioned nucleus. Phylogenies inferred from SSU rDNA sequences demonstrated a close relationship between R. polygordiae and the poorly known parasite reported from the hemolymph of the giant clam Tridacna crocea. The rhytidocystid clade diverged early in the apicomplexan radiation and showed a weak affinity to a clade consisting of cryptosporidian parasites, monocystids, and neogregarines. [ABSTRACT FROM AUTHOR]

An octospore microsporidium was found in the nymphs of Aeshna viridis, collected in intermittent streams near Novosibirsk, Siberia, Russia in 2003. Spores were uninucleate and measured 6.1±0.07 × 3.0±0.04 μm on fresh smears. The polar filament was anisofilar having 10–11 anterior coils (thicker filament diam.) and 10–11 posterior (thinner filament diam.) coils. Sporophorous vesicles were persistent and measured 12.3±0.23 × 11.9±0.20 μm. The infection was restricted to the adipose tissue and caused the formation of whitish “cysts” containing mature octospores. Based on ultrastructural similarity we consider this Siberian isolate to be Systenostrema alba, a species described from Aeshna grandis collected in Sweden ( Larsson 1988 ). Maximum likelihood, neighbor joining, and maximum parsimony analyses of the small subunit rDNA all placed Systenostrema alba (Accession no. AY953292) as the sister taxon to a clade consisting of Thelohania solenopsae, Tubulinosema ratisbonensis, and Tubulinosema acridophagus. [ABSTRACT FROM AUTHOR]

Studies higher-order phylogeny of plasmodial slime molds (Myxogastria) based on elongation factor 1-A and small subunit rRNA gene sequences. Description of Myxogastria; Basal clade consisting of Echinosteliales; Evolution in spore pigmentation.