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Seven new species of the genus Haploniscus from the deep Scotia and Weddell Seas are presented, combining morphological and molecular data (mitochondrial 16S rDNA and nuclear 18S rDNA). Haploniscus cassilatus sp. nov. , H. cucullus sp. nov. , H. weddellensis sp. nov. , H. procerus sp. nov. and H. kyrbasia sp. nov. are characterized by a prominent rostral process, the size and shape of which vary among species. The rostrum of H. microkorys sp. nov. is distinctly smaller than that of the former species, while H. nudifrons sp. nov. does not possess a rostrum. The status of the latter as separate species is obvious, owing to the stronger morphological differences. DNA was sequenced from three of the other five species. Genetic distances together with the more subtle morphological variation justify the erection of separate species. Overall morphological variations between these species are small yet noticeable and include, among others, the rostrum, the shape of the pleotelson and setation of pereopods. Our molecular data sets reveal detailed phylogenetic insights within the Haploniscus cucullus complex, supporting the monophyly of all species. We found p -distances of at least 0.0732 (16S rDNA) and 0.0140 (complete 18S rDNA) between pairs of species and show that both genes can be used as a marker for DNA taxonomy.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 655–706.  相似文献   

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Genetic variation among 20 populations of Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) in Thailand was investigated using single strand conformation polymorphism (SSCP) analysis of mitochondrial DNA sequences. From a total 641 individual parasitoids, seven distinct haplotypes containing a total of 32 polymorphic sites were observed from cytochrome oxidase subunit I (COI) sequences along with five distinct haplotypes containing a total 16 polymorphic sites from 16S rDNA sequences. Values obtained through pairwise FST comparisons and analysis of molecular variance (AMOVA) indicated significant genetic differentiation among D. longicaudata populations in Thailand. Congruent relationships showing separation of these populations into three groups were obtained from Neighbor joining and Bayesian phylogenetic tree analyses along with the use of haplotype networks. This SSCP analysis of populations of the D. longicaudata species complex is the first report using molecular population genetic methods to analyze the structure of this parasitoid species in Thailand. This may provide useful information for release of parasitoid strains to maximize their benefit in biological control programs.  相似文献   

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In the present study, three new species found in Yunnan, Southwest China were described as members of the subgenus Phortica (Ashima): P. (A.) haba An & Chen, sp. nov., P. (A.) montipagana An & Chen, sp. nov. and P. (A.) qingsongi An & Chen, sp. nov. Barcode sequences (partial sequences of the mitochondrial COI gene) were collected from 61 specimens of 16 known and the above-mentioned three new Ashima species. The intra- and interspecific pairwise K-2P (Kimura two-parameter) COI distances were analysed and a phylogenetic tree was constructed based on the barcode sequences. Species delimitation in this subgenus was supported by integrating barcodes with morphological information, in particular for the three new species, considered to be cryptic species. In addition, the diversification of lineages in the subgenus Ashima was proposed to occur in southern China and adjacent areas, suggesting specific adaptation of Ashima species to the high plateau environments.

http://zoobank.org/urn:lsid:zoobank.org:pub:69A81D0E-5993-426D-9B59-A2AC5E52BD84  相似文献   

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A taxonomic reevaluation of the paralytic shellfish toxin (saxitoxins) producing cyanobacterium Aphanizomenon flos‐aquae Ralfs ex Born. & Flah. LMECYA31 was done using morphology and 16S rRNA gene sequences. We found that strain LMECYA31 was incorrectly identified as Aph. flos‐aquae based on (a) lack of bundle formation in trichomes, (b) shape of terminal cells in the trichomes, (c) lower similarity (<97.5%) in the 16S rRNA gene sequences relative to those of Aph. flos‐aquae, and (d) comparison within a phylogenetic tree of 16S rRNA gene sequences. The shape of the terminal trichome cells and the shape and size of the vegetative cell, heterocyst, and akinete in strain LMECYA31 match characters of Aph. issatschenkoi (Ussachew) Proschkina‐Larvernko. 16S rRNA gene sequences and phylogenetic clusters constructed from 16S rRNA gene sequences support our conclusion that strain LMECYA31 should be Aph. issatschenkoi.  相似文献   

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采用数值分类和16S rDNA PCR-RFLP对分离自云南省豆科植物补骨脂(Psoralea corylifolia)、葛藤(Pueraria lobata)、杭子梢(Campylotropis macrocarpa)等宿主的24株菌及10株根瘤菌参比菌株进行了研究。数值分类结果表明, 在84%相似性水平上, 所有的菌株可分为3群:群Ⅲ为未知菌群, 群Ⅰ为慢生菌群, 群Ⅱ为快生和中慢生菌群。从依据16S rDNA PCR-RFLP分析建立的树状图来看, 在70%相似性水平上, 所有的菌株可分为5个系统发育分支:分支Ⅰ和Ⅴ没有参比菌株, 为未知分支; 分支Ⅱ为Agrobacterium-Sinorhizobium-Rhizobium, 分支Ⅲ为Mesorhizo- bium, 分支Ⅳ为Bradyrhizobium。数值分类和16S rDNA PCR-RFLP的结果部分一致, 有2株菌与A. tumefaciens IAM13129T聚在一起。  相似文献   

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采用数值分类和16S rDNA PCR-RFLP对分离自云南省豆科植物补骨脂(Psoralea corylifolia)、葛藤(Pueraria lobata)、杭子梢(Campylotropis macrocarpa)等宿主的24株菌及10株根瘤菌参比菌株进行了研究.数值分类结果表明,在84%相似性水平上,所有的菌株可分为3群:群Ⅲ为未知菌群,群Ⅰ为慢生菌群,群Ⅱ为快生和中慢生菌群.从依据16S rDNA PCR-RFLP分析建立的树状图来看,在70%相似性水平上,所有的菌株可分为5个系统发育分支:分支Ⅰ和Ⅴ没有参比菌株,为未知分支;分支Ⅱ为Agrobacterium-Sinorhizobium-Rhizobium,分支Ⅲ为Mesorhizobium,分支Ⅳ为Bradyrhizobium.数值分类和16S rDNA PCR-RFLP的结果部分一致,有2株茵与A.tumefaciens IAM13129T聚在一起.  相似文献   

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Recent studies indicate that there is a high diversity of pleurostomatid ciliates in the coastal waters of China. Here, three new congeners of Loxophyllum, L. caudatum sp. n., L. rugosum sp. n., and L. chinense sp. n., are described following observations of live cells and protargol‐impregnated specimens. All three species usually have two macronuclear nodules and prominent warts along the dorsal margin formed by clustered extrusomes. In addition, L. caudatum sp. n. is characterized by its long conspicuous tail, dot‐like cortical granules, 4 or 5 left and 9 or 10 right kineties, and a single subterminal contractile vacuole. Loxophyllum rugosum sp. n. is distinguished by possessing three prominent ridges on the left side, 7–11 right and 5–7 left kineties. Loxophyllum chinense sp. n. is characterized by having several contractile vacuoles distributed along the ventral margin, 13–18 right and 6–8 left kineties. The small subunit ribosomal DNA (SSU rDNA) sequence similarities among six congeners range from 96.46% to 99.94%. Phylogenetic trees based on the SSU rDNA sequences indicate that all Loxophyllum spp. form a well‐supported monophyletic group. A brief review of the marine and brackish Loxophyllum species is supplied and one new combination, Litonotus multiplicatus (Kahl 1931) comb. n. (basionym Loxophyllum multiplicatum Kahl 1931), and one new name, Litonotus dragescoi nom. n. (basionym L. fasciolatus Dragesco 1966), are suggested.  相似文献   

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A new needle nematode, Longidorus carniolensissp. n., recovered from the soil around the roots of grapevine Vitis vinifera L. from Slovenia, is described and illustrated. Longidorus carniolensisis an amphimictic species, characterised by females with a moderately long (L=5.6-8.2 mm) and plump (a=51-72.4, ave. 66.3) body, assuming a spiral to C-shape when heat relaxed. Head region continuous, anteriorly almost flat, lip region 23-25 μm wide; guiding ring situated posteriorly (42-47 μm, 43-50 μm in males), odontostyle long (ave. 146.6 (136-157) μm); pharyngeal glands with normal location, their nuclei of approximately equal size; tail bluntly conoidal to almost hemispherical. Males abundant, spicules slender and long (122-145 μm), ventromedian supplements 13-17, irregularly spaced, preceded by an adanal pair. Four juvenile stages present, the first stage juvenile with bluntly conoidal tail. Codes for identifying the new species when using the key by Chen et al. (1997) are: A 56, B 4, C 4, D 1, E 4, F 35, G 1, H 1, I 2. The new species is morphologically the most similar to Longidorus poessneckensis Altherr, 1974, Longidorus macrosoma Hooper, 1961, Longidorus caespiticola Hooper, 1961, Longidorus helveticus Lamberti et al., 2001, Longidorus macroteromucronatus Altherr, 1974, Longidorus pius Barsi & Lamberti, 2001, Longidorus raskii Lamberti & Agostinelli, 1993, Longidorus kheirii Pedram et al. 2008, Longidorus silvae Roca, 1993, Longidorus iuglandis Roca et al., 1985, Longidorus vinearum Bravo & Roca, 1995 and Longidorus major Roca & d'Erico, 1987, but differs from these species either by the body and odontostyle length, position of guide ring, head region and tail shape or the shape of the first stage juvenile tail. Sequence data from the D2-D3 region of the 28S rDNA distinguishes this new species from other speciesof the genus Longidorus with known sequences. Relationships of Longidorus carniolensissp. n. with other Longidorus species based on analysis of this DNA fragment and morphology are discussed.  相似文献   

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The phylogeny and potential mode of speciation of the river limpet Ancylus fluviatilis (Basommatophora) was examined using mitochondrial DNA sequences from 16S ribosomal RNA, cytochrome c oxidase subunit I (COI) and nuclear DNA from internal transcribed spacer (ITS-1) regions from 103 populations across Europe. Four highly divergent lineages were observed within Ancylus. Clade 1, representing the nominal taxon Ancylus fluviatilis (O.F. Müller, 1774), is mainly found in central and northern Europe, Clade 2 is present in a single Portuguese population, Clade 3 is distributed on the Canary islands, North Africa and the eastern Mediterranean region, whereas Clade 4 inhabits the Northern Mediterranean coasts. Phylogenetic analyses revealed an overall consistent topology of nuclear and mitochondrial gene trees. Based on a molecular clock, we estimated that the basic radiation occurred in the late Pliocene. Although clades differ significantly in size independent shell shape, morphological differentiation of lineages is not feasible without genetic data. Environmental data related to climate (precipitation, temperature, etc.) showed a significant differentiation of clades. Clade 1 dwells in relatively colder and more stable habitats than Clades 3 and 4, whose habitats in turn differ in a low or high amount of precipitation during spring and autumn, respectively. Based on the combined data sets on mitochondrial DNA, nuclear DNA, morphological and ecological differentiation, we conclude that Ancylus represents a cryptic species complex of reproductively and genetically isolated lineages. In addition, the joint analysis suggests that ecological speciation is probable to explain current patterns.  相似文献   

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We investigated the similarity of a single Euglena myxocylindracea strain, isolated originally by Bold and MacEntee, to several Euglena geniculata strains on both morphological and DNA levels. We found the three DNA stretches, consisting of fragments coding for the parts of cytoplasmic and chloroplast small subunit rRNA, and the internal transcribed spacer (ITS2) of cytoplasmic rDNA, with the combined length of 4332 nucleotides, are identical in E. myxocylindracea and E. geniculata, strain SAG 1224‐4b. Morphological differences between E. myxocylindracea and any E. geniculata strain examined were well within the range of E. geniculata variability as well. The only difference behind the distinction of E. myxocylindracea from E. geniculata is the presence of the second chloroplast in the latter. However, we were able to induce the appearance of the second chloroplast in the cells of E. myxocylindracea and its disappearance in the cells of E. geniculata by changing the composition of the culture media. We therefore conclude that E. myxocylindracea Bold and MacEntee should be regarded as an environmental form of E. geniculata Dujardin. For the first time the morphology of E. geniculata chloroplasts was shown as revealed by confocal laser microscopy.  相似文献   

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蝗总科部分种类16S rDNA的分子系统发育关系   总被引:20,自引:0,他引:20  
将自测的我国直翅目蝗总科8科8个种和从互联网GenBank中检索到相关物种的线粒体基因组:16S rDNA序列片段进行同源性比较,计算核苷酸使用频率,并构建分子系统树。在获得的480bp的序列中。A T约占70.7%,G C为29.3%,颠换取代(transversion)的速率大于或接近转换取代(transition)的速率,其中188个核苷酸位点存在变异。研究结果表明:在直翅目蝗总科有差异的188bp中,属内种间的碱基序列差异仅为1.5%,科内属间为3.5%~3.6%,科间差异为4.8%~15.8%,亚目间差异达到15.2%~25.6%。分子系统树表明:科内的属和属内的种均优先聚在一起;蝗总科8科的起源关系为:锥头蝗科→瘤锥蝗科→癞蝗科→斑翅蝗科→剑角蝗科→网翅蝗科和槌角蝗科→斑腿蝗科;锥头蝗科与瘤锥蝗科关系较近,是蝗总科内最原始的类群;槌角蝗科和网翅蝗科互为姐妹群,与最进化的斑腿蝗科关系较近;蚤蝼科为独立的一支,最先分出,似为一个亚目,与现用的分类系统有明显差别;哈螽科(螽嘶总科)和蟋蟀科聚在一起为剑瓣亚目(Ensifera),蚱科和蝗总科的8科组成短瓣亚目(Caehfera),同现用的分类系统。  相似文献   

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Cyanolichens are an assemblage of fungi and cyanobacteria from diverse, cosmopolitan habitats. Typically composed of a single species of cyanobacterium, with or without another eukaryotic alga, here we present two novel cyanobionts isolated from an undescribed tripartite lichen. This endolithic lichen was isolated from a granite cemetery tombstone from Jacksonville, FL, and contains two potentially nitrogen‐fixing cyanobionts. Employing a total evidence approach, we characterized the cyanobionts using molecular (the 16S rDNA and ITS gene region), morphological, and ecological data. Phylogenetic analyses revealed two novel taxa: Brasilonema lichenoides and Chroococcidiopsis lichenoides, both of which fell within well‐supported clades. To our knowledge, this represents the first instance of a tripartite lichen with two cyanobacterial and no eukaryotic members. These types of lichens may well represent an unexplored reservoir of cyanobacterial diversity. The specific epithets are proposed under the provisions of the International Code of Nomenclature for algae, fungi, and plants.  相似文献   

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Phyllosiphon arisari Kühn (Phyllosiphonaceae, Chlorophyta) commonly occurs in Arisarum leaves in coastal Mediterranean areas of the Iberian Peninsula and Balearic islands. The genus Phyllosiphon was first considered to be a member of the Xanthophyceae but was later transferred to the chlorophytes. However, there are few data about its morphology, ultrastructure, ecology or phylogenetic affinities. In this paper we describe the morphology of Phyllosiphon, as studied in field material and in culture; the fine structure, analysed by transmission electron microscopy; and phylogenetic relationships, inferred from DNA sequences. The siphonous filaments were seen to divide and penetrate leaf tissues. The cytoplasm divided into spherical or subspherical sporocysts producing autospores inside. Cytoplasmic remains could be observed between autospores or on their cell walls. Phylogenetic analysis of 18S rDNA and 16S rDNA sequences showed that the closest relatives of Phyllosiphon are subaerial strains of Heterochlorella, Heveochlorella and Kalinella, demonstrating that Phyllosiphon should be transferred to Trebouxiophyceae. An evolution from unicells to a siphonous thallus, and from aerophytic to endophytic and parasitic habits, is proposed for Trebouxiophyceae.  相似文献   

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  总被引:1,自引:0,他引:1  
The evolutionary importance of cryptic taxa is well documented, yet few studies have examined them with a view to conservation. In the present study, the significance of cryptic speciation in freshwater crabs is examined. Allozyme and 16S rRNA sequence data were used to explore the degree of population differentiation between mountain stream populations of two distinct freshwater crab species. Marked patterns of differentiation were evident among populations; those in close geographical proximity were characterized by the fixation of alternate alleles at certain loci, indicating that currently there is no gene flow among populations. Both allozyme and sequence data provide evidence for the recognition of at least five distinct evolutionary lineages with pronounced levels of genetic differentiation. Morphometric data failed to detect any distinct geographically intermediate population groupings. Our findings indicate the presence of five phylogeographical units, all worthy of conservation, three of which are evolutionarily significant.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 78 , 129–147.  相似文献   

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Several European species of the terrestrial slug genus Arion have been introduced into North America. A case in point is the species complex A. subfuscus s.l. which has become one of the most abundant slug taxa in North America. In Europe this complex consists of at least two cryptic species, viz. A. fuscus and A. subfuscus s.s., the latter of which is further subdivided in five strongly divergent mtDNA lineages (A. subfuscus S1–S5). In order to determine which of these A. subfsucus s.l. taxa are present in the NE USA and in order to assess their population genetic structure, we compared mtDNA, nDNA and allozyme variation between populations from the NE USA and Europe. Our results show that (1) at least A. subfuscus S1 has become successfully established in the NE USA, (2) founder effects are the most likely explanation for the loss of a large amount of molecular genetic variation in populations from the NE USA (i.e. a loss of 96% of the 16S rDNA haplotypes, 67% of the ITS1 alleles and 46% of the alleles at polymorphic allozyme loci), and (3) part of the remaining genetic variation in NE USA populations was probably due to multiple introductions from the British Isles and the European mainland, and the hybrid structure of most of these source populations. Apparently, the extreme loss of molecular genetic variation in this introduced species has not prevented it from successfully establishing and spreading in novel environments.  相似文献   

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戴仁怀  陈学新  李子忠 《昆虫学报》2008,51(10):1055-1064
首次在国内利用28S rDNA D2区段和16S rDNA基因序列,结合50个形态特征对角顶叶蝉亚科(Deltocephalinae)[半翅目(Hemiptera): 叶蝉科(Cicadellidae)]19个属进行系统发育分析研究。从无水乙醇浸泡保存的标本中提取基因组DNA并扩增了19个内群和1种外群Typhlocybinae[半翅目(Hemiptera): 叶蝉科(Cicadellidae)]种类的28S rDNA D2基因片段并测序,同时扩增了16S rDNA基因片段并测序11条,采用了GenBank中1个种类的16S rDNA同源序列。采用PAUP*4.0和MrBayes3.0两个分析软件和3种建树方法,利用同源28S D2 rDNA和16S rDNA两个基因序列与形态特征结合进行系统发育分析研究。分析结果表明,二叉叶蝉族Macrostelini是一个单系,并在角顶叶蝉亚科的系统发育中处于基部的位置,是内群中最原始的族;角顶叶蝉族Deltocephalini中除了纹翅叶蝉属Nakaharanus,其余各属构成单系;殃叶蝉族Euscelini内属的归属比较混乱,可能是一个并系群,属间差异有待进一步研究。隆额叶蝉族Paralimnini与顶带叶蝉族Athysanini是姐妹群。带叶蝉属Scaphoideus与纹翅叶蝉属Nakaharanus是姐妹群,二者与木叶蝉属Phlogotettix的关系最近,三者构成一个单系,建议将三者归为带叶蝉族Scaphoideini。研究结果还表明,小眼叶蝉族Xestocephalini和Balcluthini的系统发育位置不明,有待进一步研究。  相似文献   

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四种绒螯蟹分子分类与系统发育   总被引:15,自引:0,他引:15  
利用PCR技术,扩增了中华绒螯解、狭额绒螯蟹线粒体16SrDNA片段,经测序,与GenBank数据库中的日本绒螯解16SrDNA同源序列进行比较。结果显示,在长为376bp的16SrDNA同源序列中有33个多态性核革酸位点(8.78%),其中种间多态性核苷酸位点28个(7.45%),种间差异远大于种内差异。引入方蟹科其它近缘种类厚纹蟹、相手蟹和张口蟹的16SrDNA同源序列与上述4种绒螯蟹比较分析,MP法和NJ法构建的分子系统树表明:中华绒螯蟹与日本绒螯蟹亲缘关系最近,首先聚在一起,然后与台湾绒螯蟹聚为一支,狭额绒螯蟹则为相对独立的一支,且进化速度大于前3种绒螯蟹,但最后与前者仍聚在同一组,狭额绒螯蟹只是绒螯蟹属系统进化中的一个侧支,故本研究结果不支持Sakai(1983)和Guo等(1997)把狭额绒螯蟹和台湾绒螯蟹各自立为新属的观点。  相似文献   

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