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1.
The marine order Arthrotardigrada (class Heterotardigrada, phylum Tardigrada) is known for its conspicuously high morphological diversity and has been traditionally recognized as the most ancestral group within the phylum. Despite its potential importance in understanding the evolution of the phylum, the phylogenetic relationships of Arthrotardigrada have not been clarified. This study conducted molecular phylogenetic analyses of the order encompassing all families except Neoarctidae using nuclear 18S and 28S rRNA fragments. Data from two rare families, Coronarctidae and Renaudarctidae, were included for the first time. The analyses confirmed the monophyly of Heterotardigrada and inferred Coronarctidae as the sister group to all other heterotardigrade taxa. Furthermore, the results support a monophyletic Renaudarctidae + Stygarctidae clade, which has been previously suggested on morphology. Our data indicated that two subfamilies currently placed in Halechiniscidae are only distantly related to this family. We propose that these taxa are each elevated to family level (Styraconyxidae (new rank) and Tanarctidae (new rank)). The morphology of tardigrades is discussed in the context of the inferred phylogeny.  相似文献   

2.
A Family Level Analysis of Tardigrade Phylogeny   总被引:1,自引:1,他引:0  
In the present study a character data set suitable for cladistic analysis at the family level was developed. A data matrix consisting of 50 morphological characters from 15 families of tardigrades was analyzed by maximum parsimony. Kinorhynchs, loriciferans, and gastrotrichs were used as outgroups. The results agree with the currently accepted hypothesis that Eutardigrada and Heterotardigrada are distinct monophyletic groups. Among the eutardigrades, Eohypsibiidae was found to be a sister group to Macrobiotidae+Hypsibiidae, while Milnesiidae was the basal eutardigrade family. The basal heterotardigrade family was found to be Oreellidae. Echiniscoideans grouped with some traditional Arthrotardigrada (Renaudarctidae, Coronarctidae+Batillipedidae) suggesting that the arthrotardigrades are not monophyletic. The 18S rRNA gene sequence of Batillipes mirus Richters, 1909 and Calohypsibius schusteri Nelson & McGlothlin, 1996 were obtained and their addition to a previously published dataset supports the monophyly of Heterotardigrada and of Parachela versus Apochela within the Eutardigrada.  相似文献   

3.
The phylogeny of the family Sciaridae is reconstructed, based on maximum likelihood, maximum parsimony, and Bayesian analyses of 4809 bp from two mitochondrial (COI and 16S) and two nuclear (18S and 28S) genes for 100 taxa including the outgroup taxa. According to the present phylogenetic analyses, Sciaridae comprise three subfamilies and two genus groups: Sciarinae, Chaetosciara group, Cratyninae, and Pseudolycoriella group + Megalosphyinae. Our molecular results are largely congruent with one of the former hypotheses based on morphological data with respect to the monophyly of genera and subfamilies (Sciarinae, Megalosphyinae, and part of postulated “new subfamily”); however, the subfamily Cratyninae is shown to be polyphyletic, and the genera Bradysia, Corynoptera, Leptosciarella, Lycoriella, and Phytosciara are also recognized as non-monophyletic groups. While the ancestral larval habitat state of the family Sciaridae, based on Bayesian inference, is dead plant material (plant litter + rotten wood), the common ancestors of Phytosciara and Bradysia are inferred to living plants habitat. Therefore, shifts in larval habitats from dead plant material to living plants may have occurred within the Sciaridae at least once. Based on the results, we discuss phylogenetic relationships within the family, and present an evolutionary scenario of development of larval habitats.  相似文献   

4.
Available information about Mediterranean tardigrades regards mainly the insular and peninsular Italian coasts, but also Malta, the Alboran Sea, Spain, France, Albania, Morocco, Algeria, Tunisia, Cyprus, and Lebanon. The Mediterranean Tardigrades, more than 70 species, are Heterotardigrada, mainly the order Arthrotardigrada with several families, and the order Echiniscoidea with only the family Echiniscoididae. Coralligenous detritus seems to be the most favourable kind of sediment in which the highest values of biodiversity are reached. Halechiniscidae is the most important family in the subtidal zone, whereas Batillipedidae are more frequent in the intertidal zone. A study of 4 submarine cave populations has been carried out. Neoarctidae and Neostygarctidae, considered as the most ancient families, have only been found in the Mediterranean Sea to date. This could mean that Arthrotardigrada originated in the old Thetys Sea from which the basin of the Mediterranean Sea was formed.  相似文献   

5.
Two Gram-stain-negative, facultative anaerobic, motile, rod-shaped strains, S-B4-1UT and JOB-63a, forming small whitish transparent colonies on marine agar, were isolated from a sponge of the genus Haliclona. The strains shared 99.7% 16S rRNA gene sequence identity and a DNA-DNA hybridization value of 100%, but were differentiated by genomic fingerprinting using rep-PCRs. 16S rRNA gene sequence phylogeny placed the strains as a sister branch to the monophyletic genus Endozoicomonas (Oceanospirillales; Gammaproteobacteria) with 92.3–94.3% 16S rRNA gene sequence similarity to Endozoicomonas spp., 91.9 and 92.1% to Candidatus Endonucleobacter bathymodiolin, and 91.9 to 92.1% to the type strains of Kistimonas spp. Core genome based phylogeny of strain S-B4-1UT confirmed the phylogenetic placement. Major fatty acids were summed feature 3 (C16:1 ω7c/C16:1 ω6c) and 8 (C18:1 ω7c/C18:1 ω6c) followed by C10:0 3-OH, C16:0, and C18:0. The G + C content was 50.1–51.4 mol%. The peptidoglycan diamino acid of strain S-B4-1UT was meso-diaminopimelic acid, the predominant polyamine spermidine, the major respiratory quinone ubiquinone Q-9; phosphatidylethanolamine, phosphatidylglycerol and phosphatidylserine were major polar lipids. Based on the clear phylogenetic distinction, the genus Parendozoicomonas gen. nov. is proposed, with Parendozoicomonas haliclonae sp. nov. as type species and strain S-B4-1UT (= CCM 8713T = DSM 103671T = LMG 29769T) as type strain and JOB-63a as a second strain of the species. Based on the 16S rRNA gene sequence phylogeny of the Oceanospirillales within the Gammaproteobacteria, the Endozoicomonaceae fam. nov. is proposed including the genera Endozoicomonas, Parendozoicomonas, and Kistimonas as well as the Candidatus genus Endonucleobacter.  相似文献   

6.
Providing accurate animals’ phylogenies rely on increasing knowledge of neglected phyla. Tardigrada diversity evaluated in broad phylogenies (among phyla) is biased towards eutardigrades. A comprehensive phylogeny is demanded to establish the representative diversity and propose a more natural classification of the phylum. So, we have performed multilocus (18S rRNA and 28S rRNA) phylogenies with Bayesian inference and maximum likelihood. We propose the creation of a new class within Tardigrada, erecting the order Apochela (Eutardigrada) as a new Tardigrada class, named Apotardigrada comb. n. Two groups of evidence support its creation: (a) morphological, presence of cephalic appendages, unique morphology for claws (separated branches) and wide‐elongated buccopharyngeal apparatus without placoids, and (b) phylogenetic support based on molecular data. Consequently, order Parachela is suppressed and its superfamilies erected as orders within Eutardigrada, maintaining their current names. We propose a new classification within the family Echiniscidae (Echiniscoidea, Heterotardigrada) with morphological and phylogenetic support: (a) subfamily Echiniscinae subfam. n., with two tribes Echiniscini tribe n. and Bryodelphaxini tribe n.; (b) subfamily Pseudechiniscinae subfam. n., with three tribes Cornechiniscini tribe n., Pseudechiniscini tribe n. and Anthechiniscini tribe n.; and (c) subfamily Parechiniscinae subfam. n., with two tribes Parechiniscini tribe n. and Novechiniscini tribe n. Reliable biodiversity selection for tardigrades in broad phylogenies is proposed due to biased analyses performed up to now. We use our comprehensive molecular phylogeny to evaluate the evolution of claws in the clawless genus Apodibius and claw reduction across the Tardigrada tree of life. Evolutionary consequences are discussed.  相似文献   

7.
We describe the morphology and 18S rDNA phylogeny of Bryophryoides ocellatus n. g., n. sp., a bryophryid ciliate inhabiting in situ soil percolates from Idaho, U.S.A. The new genus is distinguished from other bryophryid genera by a combination of the following features: (1) kreyellid (irregularly meshed) silverline pattern, (2) polymorphic adoral organelles in the preoral suture, (3) absence of vestibular kineties. In phylogenetic analyses, Bryophryoides ocellatus is most closely related to Bryophrya gemmea. The 18S rDNA sequence pairwise distance of 2% between these genera, while similar to that between many colpodidan species, exceeds that between some colpodidan genera (e.g. Mykophagophrys and Pseudoplatyophrya, 1.1%), further supporting establishment of the new genus. Topology hypothesis testing strongly supports the monophyly of the Colpodida including the bryophryids. Despite weak nodal support, tests of topology constraints narrowly reject the non-monophyly of the sequenced Bryophryidae (Bryophrya + Bryophryoides + Notoxoma). Likewise, the monophyletic origin of the sequenced Bryophryidae is indicated in the phylogenetic networks though with low support.  相似文献   

8.
The spider mite sub-family Tetranychinae includes many agricultural pests. The internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes and the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA have been used for species identification and phylogenetic reconstruction within the sub-family Tetranychinae, although they have not always been successful. The 18S and 28S rRNA genes should be more suitable for resolving higher levels of phylogeny, such as tribes or genera of Tetranychinae because these genes evolve more slowly and are made up of conserved regions and divergent domains. Therefore, we used both the 18S (1,825–1,901 bp) and 28S (the 5′ end of 646–743 bp) rRNA genes to infer phylogenetic relationships within the sub-family Tetranychinae with a focus on the tribe Tetranychini. Then, we compared the phylogenetic tree of the 18S and 28S genes with that of the mitochondrial COI gene (618 bp). As observed in previous studies, our phylogeny based on the COI gene was not resolved because of the low bootstrap values for most nodes of the tree. On the other hand, our phylogenetic tree of the 18S and 28S genes revealed several well-supported clades within the sub-family Tetranychinae. The 18S and 28S phylogenetic trees suggest that the tribes Bryobiini, Petrobiini and Eurytetranychini are monophyletic and that the tribe Tetranychini is polyphyletic. At the genus level, six genera for which more than two species were sampled appear to be monophyletic, while four genera (Oligonychus, Tetranychus, Schizotetranychus and Eotetranychus) appear to be polyphyletic. The topology presented here does not fully agree with the current morphology-based taxonomy, so that the diagnostic morphological characters of Tetranychinae need to be reconsidered.  相似文献   

9.
The monophyly of the muricid subfamily Rapaninae has recently been confirmed with molecular techniques, but its composition and the relationships among its constituent genera remain unclear. We use four genes (28S rRNA, 12S rRNA, 16S rRNA and cytochrome c oxidase subunit I, COI) to construct a Bayesian phylogeny of 80 rapanine species (73% of the approximately 109 currently accepted), representing 27 of the 31 nominal genera. This is the most complete phylogeny of this taxonomically confusing subfamily yet produced. We propose a revised phylogenetic classification of the Rapaninae, assigning the recognized species to 28 genera. Most of the morphologically-defined rapanine genera are considered valid, including Purpura, Drupa, Thais and Nassa, but many of them are here restricted or redefined so that they are monophyletic. In particular the familiar genus Thais is narrowly restricted to a single species. Many groups previously accepted as subgenera, including Mancinella, Vasula, Thalessa and Thaisella, are here accorded full generic rank. We describe one new genus, Indothais. While we do not formally alter species-level taxonomy, we show molecular evidence for two cryptic species and several instances of probable species synonymy. We estimate the age of diversification of the Rapaninae as Late Cretaceous (75.9 Ma) and of many of its genera as Miocene.  相似文献   

10.
Pfiesteria piscicida is a harmful bloom-forming alga that has received a great deal of attention due to its potential association with large fish kills and neurological problems in humans. Since the discovery of Pfiesteria, several other Pfiesteria-like dinoflagellates (PLDs) have also been identified. Genetic identification and phylogenetic relationships among the PLDs commonly utilize sequence data from the genes and spacers of the ribosomal DNA (rDNA) operon. Of these, the internal transcribed spacers (ITSs) have been previously shown to fold into secondary structures that are critical for proper ribosomal processing. In this study, we modeled the secondary structure of the second internal transcribed spacer (ITS2) from 16 PLDs (as well as an outgroup taxon) using phylogenetic comparative methods and minimum free energy. The secondary structural models predicted for these dinoflagellates consisted of four paired helices separated by five unpaired regions, consistent with those reported from many eukaryotes. All of the structures were highly stable (ΔG = ?66.1 to ?122.3 kcal·mol at 37 °C) and several structural characters were found to be conserved either across the PLDs or were specific to monophyletic subgroups, strengthening previously inferred phylogenetic relationships among taxa. Additionally, an 18 bp motif was identified in the PLDs whose position corresponds to a ribosomal processing site described from other eukaryotes. Potential applications of these ITS2 secondary structures include utility in strain and species identification, phylogenetic inference and serving as a tool for identifying and excluding rDNA pseudogenes when assessing biodiversity within the PLDs.  相似文献   

11.
Gene structure data can substantially advance our understanding of metazoan evolution and deliver an independent approach to resolve conflicts among existing hypotheses. Here, we used changes of spliceosomal intron positions as novel phylogenetic marker to reconstruct the animal tree. This kind of data is inferred from orthologous genes containing mutually exclusive introns at pairs of sequence positions in close proximity, so-called near intron pairs (NIPs). NIP data were collected for 48 species and utilized as binary genome-level characters in maximum parsimony (MP) analyses to reconstruct deep metazoan phylogeny. All groupings that were obtained with more than 80% bootstrap support are consistent with currently supported phylogenetic hypotheses. This includes monophyletic Chordata, Vertebrata, Nematoda, Platyhelminthes and Trochozoa. Several other clades such as Deuterostomia, Protostomia, Arthropoda, Ecdysozoa, Spiralia, and Eumetazoa, however, failed to be recovered due to a few problematic taxa such as the mite Ixodes and the warty comb jelly Mnemiopsis. The corresponding unexpected branchings can be explained by the paucity of synapomorphic changes of intron positions shared between some genomes, by the sensitivity of MP analyses to long-branch attraction (LBA), and by the very unequal evolutionary rates of intron loss and intron gain during evolution of the different subclades of metazoans. In addition, we obtained an assemblage of Cnidaria, Porifera, and Placozoa as sister group of Bilateria + Ctenophora with medium support, a disputable, but remarkable result. We conclude that NIPs can be used as phylogenetic characters also within a broader phylogenetic context, given that they have emerged regularly during evolution irrespective of the large variation of intron density across metazoan genomes.  相似文献   

12.
A molecular phylogeny is used to analyze the diversification history of Adesmia ser. psoraleoides, and its implications for understanding the historical assembly of the grasslands in the highlands of southern Brazil. All species of A. ser. psoraleoides were sampled, including multiple accessions for each species, plus representative species of the rest of Adesmia covering its geographic distribution. Phylogenetic analyses were based on nuclear and plastid DNA sequences, and a plastid matK phylogeny was dated. A. ser. psoraleoides is a well-supported monophyletic group, nested within the series bicolores, muricatae, subnudae, longisetae and candidae. The stem of A. ser. psoraleoides is c. 11 Mya, but most extant species diversified c. 3–5 Mya, suggesting that the flora of the subtropical grasslands of southern Brazil was assembled recently, co-incident with the expansion of other tropical grassland systems globally.  相似文献   

13.
Strain 28bB2TT is a sulfate-reducing bacterium isolated in a previous study, obtained from a p-xylene-degrading enrichment culture. Physiological, phylogenetic and genomic characterizations of strain 28bB2TT were performed to establish the taxonomic status of the strain. Cells of strain 28bB2TT were short oval-shaped (0.8–1.2 × 1.2–2.7 μm), motile, and Gram-negative. For growth, the optimum pH was pH 6.5–7.0 and the optimum temperature was 28–32 °C. Strain 28bB2TT oxidized toluene but could not utilize p-xylene. Sulfate and thiosulfate were used as electron acceptors. The G + C content of the genomic DNA was 53.8 mol%. The genome consisted of an approximately 8.3 Mb of chromosome and two extrachromosomal elements. On the basis of 16S rRNA gene analysis, strain 28bB2TT was revealed to belong to the genus Desulfosarcina, with high sequence identities to Desulfosarcina ovata oXyS1T (99.5%) and Desulfosarcina cetonica DSM 7267T (98.7%). Results of Average Nucleotide Identity (ANI) calculation and digital DNA–DNA hybridization (dDDH) analysis showed that the strain 28bB2TT should be classified as a subspecies under D. ovata. Based on physiological and phylogenetic data, strain 28bB2TT (=NBRC 106234 =DSM 23484) is proposed as the type strain of a novel species in genus Desulfosarcina, Desulfosarcina ovata subsp. sediminis subsp. nov.  相似文献   

14.
We collected Rimaleptus binucleatus from soil in the surroundings of the town of Ulsan, South Korea. Its morphology and 18S rRNA gene were studied using standard methods. This possibly widely distributed species is characterized by: (i) a size of about 170–400 × 20–65 μm; (ii) a narrowly to cylindrically dileptid body with proboscis occupying about 30–65% of body length; (iii) two dorsal contractile vacuoles; (iv) two size groups of rod-shaped extrusomes; and (v) about 18–29 ciliary rows, 4–6 of them anteriorly differentiated into a staggered dorsal brush. Phylogenetic analyses of five new rhynchostomatian 18S rRNA gene sequences supported monophylies of the orders Tracheliida and Dileptida, but revealed that the genera Rimaleptus and Pseudomonilicaryon are polyphyletic. Monophyly of genera with two macronuclear nodules was consistently rejected, but monophylies of dileptids with many scattered macronuclear nodules and of dileptids with moniliform macronucleus and multi-rowed dorsal brush could not be excluded by statistical topology tests. Nevertheless, phylogenetic network analyses indicated considerable conflict in the phylogenetic signal provided by the 18S rRNA gene to resolve unambiguously relationships among dileptid genera.  相似文献   

15.
We inferred the phylogenetic relationships among members of the Poecilia sphenops species complex to resolve the colonization process and radiation of this group in Central America. We analyzed 2550 base pairs (bp) of mitochondrial DNA (mtDNA), including ATP synthase 6 and 8, cytochrome oxidase subunit I and NADH dehydrogenase subunit 2 genes, and 906 bp of the nuclear S7 ribosomal protein of 86 ingroup individuals from 61 localities spanning most of its distribution from Mexico to Panama. Our mitochondrial data rendered a well-supported phylogeny for the P. sphenops complex that differed with the nuclear data set topology, which did not recover the monophyly of the P. mexicana mitochondrial lineage. Coalescent-based simulations tests indicated that, although hybridization cannot be completely ruled out, this incongruence is most likely due to incomplete lineage sorting in this group, which also showed the widest geographic distribution. A single colonization event of Central America from South America was estimated to have occurred between the early Paleocene and Oligocene (53–22 million years ago). Subsequently, two largely differentiated evolutionary lineages diverged around the Early Oligocene–Miocene (38–13 million years ago), which are considered two separate species complexes: P. sphenops and P. mexicana, which can also be distinguished by their tricuspid and unicuspid inner jaw teeth, respectively. Ultimately, within lineage diversification occurred mainly during the Miocene (22–5 million years ago). All major cladogenetic events predated the final closure of the Isthmus of Panama. The allopatric distribution of lineages together with the long basal internodes suggest that vicariance and long term isolations could be the main evolutionary forces promoting radiation in this group, although dispersal through water barriers might also have occurred. Lastly, our results suggest the need to review the current species distribution and taxonomy of the P. sphenops complex sensu lato.  相似文献   

16.
Numerous taxa show ancient intertropical disjunct distributions. Many can be explained by well-known processes of historical vicariance, such as the breakup of Gondwanaland. Others, such as Asian–Neotropical divergences are not as well understood. To clarify the phylogenetic position and understand biogeographic and temporal origins of the geographically disjunct and morphologically unique genera of hinged-teeth snakes, Scaphiodontophis (n = 1) and Sibynophis (n = 9; Colubridae), we inferred a time-calibrated phylogeny with additional 107 taxa representing the superfamily Colubroidea using four genes (c-mos, cyt-b, ND2, RAG-1; 3085 bp). We used this tree to estimate ancestral areas for the group. The results show that Scaphiodontophis is sister to Sibynophis, both originated in the late Eocene/Oligocene in Asia and likely dispersed through Beringia to the New World, but unlike other snake groups left no extant species in temperate North America. Current recognition of Scaphiodontophiinae renders Colubrinae paraphyletic, and we resurrect the previously named subfamily Sibynophiinae to encompass both genera and use the tribes Sibynophiini (Sibynophis) and Scaphiodontophiini (Scaphiodontophis) to highlight the geographically distinct areas occupied by these taxa. These results suggest that intercontinental dispersal with extinction in intermediate areas can explain puzzling patterns of ancient intertropical disjunct distributions.  相似文献   

17.
Two marine bacterial strains designated Y2-1-60T and GM1-28 were isolated from sediments of cordgrass and mangrove along the Luoyang estuary in Quanzhou Bay, China, respectively. Both strains were Gram-staining-negative, straight rod-shaped, non-flagellum, facultatively anaerobic, nitrogen-fixing, and did not contain carotenoid pigment. Catalase activities were found to be weak positive and oxidase activities negative. The 16S rRNA gene sequences of the two strains were identical and had maximum similarity of 98.0% with Maribellus luteus XSD2T, and of <94.5% with other species. ANI value (96.9%) and DDH estimate (71.5%) between the two strains supported that they belonged to the same species. ANI value and DDH estimate between the two strains and M. luteus XSD2T was 74.3% and 19.4%, respectively, indicating that they represent a novel species. Phylogenetic analysis based on 16S rRNA gene and phylogenomic analysis indicated that strains Y2-1-60T and GM1-28 formed a monophyletic branch within the genus Maribellus. The respiratory quinone was menaquinone MK-7. The major fatty acid (>10%) consisted of iso-C15:0, and iso-C17:0 3-OH. The polar lipids consisted of phosphatidylethanolamine and several unidentified lipids. The genomic G + C contents were 41.9–42.0 mol%. Gene annotation revealed that strains Y2-1-60T and GM1-28 contained a set of nif gene cluster (nifHDKENB) responsible for nitrogen fixation. Based on the above characteristics, strains Y2-1-60T and GM1-28 represent a novel species within the genus Maribellus. Thus, Maribellus sediminis sp. nov. is proposed with type strain Y2-1-60T (=MCCC 1K04285T = KCTC 72884T), isolated from cordgrass sediment and strain GM1-28 (=MCCC 1K04384 = KCTC 72880), isolated from mangrove sediment.  相似文献   

18.
Paraurosomoida indiensis gen. nov., sp. nov. was isolated from a soil sample collected from Kyongnosla Alpine Sanctuary in the Eastern Himalayas. The present study reports the morphology, morphogenesis, and molecular phylogeny inferred from 18S rDNA sequence. The study is based on live and protargol-impregnated specimens. Paraurosomoida indiensis is very flexible, measures about 90 × 25 μm in life and possesses citrine cortical granules randomly distributed singly and in small linear groups. Paraurosomoida indiensis has undulating membranes nearly in Oxytricha pattern; only 11 frontal-ventral cirri due to lack of all pretransverse ventral and transverse cirri; one dorsomarginal row and three bipolar dorsal kineties. Divisional morphogenesis resembles oxytrichids involving six parental cirri in primordia formation. Anlagen V and VI for both proter and opisthe are formed from two primary primordia originating from disaggregated cirri V/4 and V/3 respectively. Three dorsal kineties develop from within row anlagen without a kinety 3 fragmentation. Molecular analyses consistently place P. indiensis with soft bodied oxytrichids.  相似文献   

19.
Myxobolus hilarii n. sp. was described, based on morphology, histology, ultrastructure and 18S rDNA sequencing, infecting the kidney of Brycon hilarii (Valenciennes 1850) (Characiformes: Bryconidae) taken from fish farms in the state of São Paulo, Brazil. Thirteen specimens of B. hilarii were examined and 100% had round, white plasmodia in the kidney. The mature myxospores were rounded, measuring 11.5 ± 0.8 (9.8–13.4) μm in length, 11.0 ± 0.7 (9.7–12.4) μm in width and 7.6 ± 1.0 (6.7–9.0) μm in thickness. Polar capsules were elongated and of equal size, with 6.5 ± 0.4 (6.0–7.2) μm in length and 4.0 ± 0.2 (3.6–5.3) μm in width and their polar filaments had 5 to 7 coils. Histological analysis revealed plasmodial development in the renal tubules, causing compression and deformation of adjacent tissues and destruction of renal tubule cells. Ultrastructural analysis showed direct contact between the plasmodial wall and the host tissue and asynchronous plasmodial development. The phylogenetic analysis of South American myxobolids, based on 18S rDNA sequencing, showed the myxosporeans grouping into two main clades. M. hilarii n. sp. appears as sister species of Myxobolus piraputangae.  相似文献   

20.
A new polypore, Perenniporia tibetica, collected in Xizang (Tibet), southwestern China, is described and illustrated on the basis of morphological and molecular characters. Perenniporia tibetica is characterized by an annual growth habit, resupinate basidiocarps with a creambuff to pinkish-buff pore surface and white to cream-colored rhizomorphs, a dimitic hyphal system with slightly dextrinoid and distinctly cyanophilous skeletal hyphae, and basidiospores that are ellipsoid, truncate or not, strongly dextrinoid, and cyanophilous, 6.7–8.7 × 5.3–6.8 μm. Its preliminary phylogenetic relationships are inferred based on sequence data from the ribosomal ITS and LSU regions, both suggesting that P. tibetica forms a distinct lineage in the genus Perenniporia.  相似文献   

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