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Results for nuclear ITS sequences were combined with previously obtained data from cpDNA restriction site studies to provide a comprehensive molecular phylogeny for subtribe Helianthinae. Results from the two molecular data sets were mostly congruent for basally diverging branches of the subtribe. Based on the results, combined with morphological observations, the basally diverging branches are placed in six genera, including one newly described. Bahiopsis is resurrected to accommodate species previously placed in Viguiera subgenus Bahiopsis . Calanticaria is newly proposed for the five species of Viguiera ser. Brevifolieae . Heliomeris is retained for the group sometimes included within Viguiera as sect. Heliomeris . Hymenostephium is revived and enlarged to include a number of species of similar habit and involucre, including members of Viguiera sect. Diplostichis , Haploca-lymma and Garcilassa . Although cpDNA results place the morphologically distinctive Sclerocarpus within the clade including species of Hymenostephium , the ITS data were consistent with morphology in suggesting it to be a distinctive lineage.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 65–76.  相似文献   

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Sequence data for internal transcribed spacer (ITS) and partial external transcribed spacer (ETS) regions were combined in a phylogenetic analysis with previously obtained plastid DNA restriction site data to provide a comprehensive molecular phylogenetic hypothesis for derived members of subtribe Helianthinae. Analyses of the two molecular datasets provided conflicting evidence on relationships among some groups, supporting the hypothesis that hybridization has played a significant role in the divergence of the subtribe. A revised generic‐level classification is presented that divides the approximately 350 species of the subtribe among 21 genera. The paraphyletic Viguiera is narrowed to embrace only the type species, V. dentata. Four newly described genera, Dendroviguiera, Gonzalezia, Heiseria and Sidneya, are composed of species formerly included in Viguiera. Aldama is expanded to include 118 species extending from southwestern North America and Mexico to South America. This requires 116 new combinations, including 58 that were recently transferred into Rhysolepis, which is a synonym of Aldama, based on molecular phylogenetic results. One species of Viguiera is transferred to Tithonia, and two combinations in Hymenostephium are validated. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 311–331.  相似文献   

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毛茛科分子系统发育研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
刘慧杰  谢磊 《西北植物学报》2016,36(9):1916-1924
毛茛科(Ranunculaceae)在被子植物的系统演化中占有十分重要的地位,其系统位置和科下演化关系一直备受争议。近20多年的分子系统学研究表明,以往基于形态学的分类系统与分子系统学研究结果存在巨大差异。通过形态学性状界定的绝大多数亚科都没有得到分子系统学支持。此外,通过形态学确定的一些属如升麻属(Cimicifuga)、黄三七属(Souliea)、獐耳细辛属(Hepatica)、白头翁属(Pulsatilla)和水毛茛属(Batrachium)等,根据分子系统学研究均应予以归并。而分子系统学研究也确立了一些类群的属级地位,如露蕊乌头属(Gymnaconitum)等。以中国分布的毛茛科植物为例,通过以往分子系统学研究,共有10个属被归并,2个属新被确立。然而,毛茛科分子系统学研究对于科下许多类群之间的关系目前仍然没有得到很好的解决,如毛茛亚科和翠雀族等类群的系统发育关系仍需要进行深入研究后方能确定。该文对近年来国内外有关毛茛科的分子系统学研究进展进行了综述,并对该科尚存的一些问题和未来的研究方向进行了讨论。  相似文献   

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A revision of the genus Calvoa Hook. f. (Melastomataceae) is presented. Principal Component Analyses (PCA) and Cluster Analyses (UPGMA) were performed to elucidate three cases of difficult species delimitation and infraspecific variation, with the following results. (1) The separation between C. crassinoda Hook. f. and C. grandifolia Cogn. was clear in the results obtained with both methods. (2) The group of the West-Central African species Calvoa angolensis A. Fern. & R. Fern., C. calliantha Jacq.-Fél., C. monticola A. Chev., C. pulcherrima Gilg ex Engl., C. sapinii De Wild., C. seretii De Wild., C. sinuata Hook. f. and C. subquinquenervia De Wild, proved difficult to resolve with either analysis, but the Cluster Analysis produced results which are more consistent with the identification of the specimens. (3) Neither of the two analyses supported the recognition of infraspecific categories in Calvoa orientalis Taub. Eighteen species are recognized in the genus. The new species Calvoa Jacques-felixii E. Figueiredo is described and the new combination Calvoa seretii subsp. wildemaniana (Exell) E. Figueiredo is made. Four lectotypes are designated. The conservation status of some taxa is discussed. Six species are considered rare and possibly under threat.  相似文献   

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In der herkömmlichen Formulierung der Homologiekriterien (vgl. Remane 1956: 58) wird das Wort “homolog” sowohl im Sinne von “gefügegleich” als auch “korrelierbar mit anderen Merkmalen” verwendet. Sie stellen Grundsätze auf und geben, ohne logische Unterscheidung, Wege an, diese Ziele zu erreichen. Als Ursache dieser Verwirrung wird die mangelhafte Unterscheidung der beiden Typuskonzepte nachgewiesen, welche in der Vergleichenden Morphologie einerseits und in der Taxonornie andererseits sowohl zur Musterfixierung als auch zur Mustererkennung Verwendung finden: Merkmalsleerer Gefügetypus und merkmalsgesättigter Korrelationstypus. Zu jedem der beiden Typuskonzepte gehört ein Verfahren, das angibt, wie mit den schwierigeren Fällen jeweils zu verfahren sei. Das Typologische Beweisverfahren wird näher dargestellt. Die in den Homologiekriterien niedergelegten Sätze können nach entsprechender Umformulierung in der aus Schema 10 ersichtlichen Weise auf die beiden Verfahren verteilt werden.  相似文献   

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用光学显微镜和扫描电镜研究了分布于中国西南地区的当归属(Angelica L.)16种植物的花粉形态,其中有7种植物的花粉形态为首次报道。研究结果表明当归属植物花粉粒较大,分化明显,包含了伞形科花粉的原始、中等进化和进化的类型,其形态以菱形、椭圆形、近长方形、赤道收缩形为主,萌发孔为角孔或边孔,从花粉的这种多类型证明该地区的当归属植物既起源古老同时又在不断分化着。从孢粉学角度初步分析了当归属的属下系统,为该属植物种的划分及系统演化关系的探讨提供依据。  相似文献   

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中国栎属植物花粉形态及其系统学意义   总被引:5,自引:0,他引:5       下载免费PDF全文
曹明  周浙昆 《广西植物》2002,22(1):14-18
从系统学分类学的角度出发 ,对国产栎属 31个种的花粉进行了光学显微镜和扫描电镜观察。研究结果表明栎属的花粉萌发孔对该属的系统与分类无太大的参考价值 ;但栎属的花粉纹饰有颗粒状、聚颗粒状两种主要类型 ,具有重要的系统学分类学价值。花粉形态的研究结果支持将栎属植物划分为常绿类与落叶类的观点 ;栎属巴东栎组植物的花粉纹饰在种间存在分化 ,花粉形态的研究结果支持将巴东栎组至少划分为两个不同类群的观点 ;在佐以其他证据的情况下 ,栎属植物的花粉纹饰还具有重要的分类学价值  相似文献   

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Five morphologically similar species of Acrapex Hampson (Lepidoptera, Noctuidae, Noctuinae, Apameini), from sub-Saharan Africa are reviewed, including four new species that are described: Acrapex mondogeneta Le Ru n. sp., A. mubale Le Ru n. sp., A. robe Le Ru n. sp. and A. rubona Le Ru n. sp. These five species belong to a species complex that we hereby define as the Acrapex minima group. Host plants of three species are recorded; Acrapex minima is recorded for the first time on a host plant, Digitaria natalensis Stent; A. mondogeneta on Hyparrhenia hirta (L.) Stapf and A. rubona on Imperata cylindrica (L.) P. Beauv. We also conducted molecular phylogenetics (using both Bayesian inference and maximum likelihood) and molecular species delimitation analyses (Poisson tree processes) on a six gene multi-marker dataset (four mitochondrial and two nuclear gene fragments; 4582 nucleotides in length) of 42 specimens and 22 species, including 23 specimens from the Acrapex minima group. The results of the corresponding analyses support the monophyly of the group and the species status of the newly described taxa.  相似文献   

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四川前胡属的花粉形态及系统学意义   总被引:8,自引:3,他引:8       下载免费PDF全文
通过光学显微镜和扫描电镜观察了前胡属 Peucedanum L.7种植物的花粉形态 .研究结果表明 :该属花粉为三棱长球形 ;三孔沟 ,边孔 ;外壁两层 ,层次分明 .根据花粉形态可归为 :矩形型和赤道收缩形型二个类型 ,其演化趋势为矩形型→赤道收缩形型 .研究结果支持了关于前胡属在伞形科中是一个较自然和较进化的类群的观点 .本文从孢粉学角度还初步分析了该属的属下系统 ,为该属的系统学研究提供基础资料  相似文献   

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The advantages of nucleotide sequence data for studying phylogeny have been shown to include number of potential characters available for comparison, rate independence between molecular and morphological evolution, and utility of molecular data for modeling patterns of nucleotide substitution. Potential pitfalls have also been revealed and include difficulties of inferring positional homology, incongruence between organismal and gene genealogies, and low likelihood of recovering the correct phylogeny given certain patterns in the timing of speciation events. Statistical methods for comparing phylogenetic hypotheses have been used to assess the reliability of alternative trees for ascaridoid nematodes. Based on partial ribosomal RNA sequences, tree topologies inconsistent with monophyly of the Ascaridinae were significantly worse by maximum likelihood inference. The topology of the maximum parsimony tree based on full-length sequences of 18S rRNA and 300 nucleotides of Cytochrome oxidase II for 13 ascaridoid species was generally consistent with traditional taxonomic expectations at lower ranks, but inconsistent with most proposed arrangements at higher taxonomic levels.  相似文献   

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The forest swallow Petrochelidon fuliginosa is a little‐known species endemic to lowland forests in central Africa; for lack of access to high‐quality genetic material, the species has been omitted from all previous molecular phylogenetic studies of the swallows. The species is currently placed in the genus Petrochelidon, within the ‘mud‐nester’ clade of swallows, yet its plumage, morphology, and nesting behavior do not align well with those of other major swallow lineages. As a consequence, upon securing recent specimens and high‐quality tissue samples, we sequenced DNA from two mitochondrial genes and one nuclear marker to place this species in the swallow phylogenetic tree. Our results placed the forest swallow firmly within the ‘mud nester’ clade, but outside of the clade corresponding to Petrochelidon. This outcome led us to document and describe formally a distinct, generic‐level lineage of swallow endemic to the Lower Guinean forest region of central Africa.  相似文献   

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Twelve morphologically similar species of Acrapex Hampson 1894, (Lepidoptera, Noctuidae, Noctuinae, Apameini, Sesamiina), from Western, Central and Eastern Africa are reviewed. Eight of these species are new to science and are described: Acrapex akunamatata n. sp. and A. incrassata n. sp. from Kenya; A. gracilis n. sp., A. iringa n. sp., A. lukumbura n. sp. and A. rungwe n. sp. from Tanzania; A. soyema n. sp. from Ethiopia; and A. zoutoi n. sp. from Benin. All 12 species belong to a species complex that we hereby define as the Acrapex apicestriata group. Host-plants for three of the new species are recorded: Setaria incrassata (Hochst.) Hack. for Acrapex incrassata; Cymbopogon pospishilii (K. Schum.) C.E. Hubb. for A. rungwe; and Andropogon perligulatus Stapf. for A. zoutoi. We also conducted molecular phylogenetic analyses (using maximum likelihood and Bayesian inference) on a six gene multimarker molecular dataset (four mitochondrial and two nuclear gene fragments; 4581 nucleotides in length) consisting of 15 Acrapex species (including seven species from the apicestriata group) and four outgroups species from the subtribe Sesamiina (from genera Busseola Thurau 1904, Sciomesa Tams & Bowden 1953, Pirateolea Moyal, Le Ru, Conlong, Cugala, Defabachew, Matama-Kauma, Pallangyo & Van den Berg 2010 and Sesamia Boisduval & Guenée 1852). Both maximum likelihood and Bayesian inference analyses yield a similar and well-supported topology, which supports the monophyly of the apicestriata group.  相似文献   

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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.  相似文献   

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Palynological characters of 18 species belonging to seven genera of the traditional subfamily Alsinoideae including Arenaria, Cerastium, Eremogone, Lepyrodiclis, Minuartia, Sabulina and Stellaria were studied in detail using light and scanning electron microscopy. Pollen grains of subfamily Alsinoideae are subspheroidal or prolate, pantoporate and 20.04 to 51.4 µm in size, prominent and sunken apertures uniformly distributed on the pollen surface. Two types of pollen grain ornamentation were observed, i.e. microechinate-punctate or microechinate-perforate. Echini are present on the surface of the pollen of all investigated species with medium, dense, or sparse echinodensity. These species exhibit variation in polar view, equatorial diameter, number of apertures, exine thickness, diameter of pore, appendages per pore, pore ornamentation, echini arrangement, echinidensity and shape of pollen. Based on qualitative characters, a dichotomous key has been developed for quick and easy identification. The present investigation contributes to the systematic approach using palynological characteristics and correct identification of species for members of subfamily Alsinoideae (Caryophyllaceae).  相似文献   

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  总被引:4,自引:0,他引:4  
The Cerithioidea is a very diverse group of gastropods with ca. 14 extant families and more than 200 genera occupying, and often dominating, marine, estuarine, and freshwater habitats. While the composition of Cerithioidea is now better understood due to recent anatomical and ultrastructural studies, the phylogenetic relationships among families remain chaotic. Morphology-based studies have provided conflicting views of relationships among families. We generated a phylogeny of cerithioideans based on mitochondrial large subunit rRNA and flanking tRNA gene sequences (total aligned data set 1873 bp). Nucleotide evidence and the presence of a unique pair of tRNA genes (i.e., threonine + glycine) between valine-mtLSU and the mtSSU rRNA gene support conclusions based on ultrastructural data that Vermetidae and Campanilidae are not Cerithioidea, certain anatomical similarities being due to convergent evolution. The molecular phylogeny shows support for the monophyly of the marine families Cerithiidae [corrected], Turritellidae, Batillariidae, Potamididae, and Scaliolidae as currently recognized. The phylogenetic data reveal that freshwater taxa evolved on three separate occasions; however, all three recognized freshwater families (Pleuroceridae, Melanopsidae, and Thiaridae) are polyphyletic. Mitochondrial rDNA sequences provide valuable data for testing the monophyly of cerithioidean [corrected] families and relationships within families, but fail to provide strong evidence for resolving relationships among families. It appears that the deepest phylogenetic limits for resolving caenogastropod relationships is less than about 245--241 mya, based on estimates of divergence derived from the fossil record.  相似文献   

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The Asian (nandid) and Afro‐Neotropical (polycentrid) leaffishes represent two superficially similar, but historically poorly diagnosed families – a situation resulting in a convoluted systematic history. Here, and including for the first time in a molecular study all leaffish genera, we generate a hypothesis of the phylogenetic history of both groups. We analyse a multilocus molecular data set encompassing 257 acanthomorph taxa, carry out a survey and assessment of selected osteological characters for the polycentrid leaffishes and also provide a reanalysis of previously published morphological data. Our results confirm: (1) that the Polycentridae and Nandidae are only remotely related, and hence, the classic leaffishes are diphyletic; (2) that the Polycentridae is monophyletic, with new skeletal synapomorphies being congruent with molecular data in placing the enigmatic Afronandus – a taxon that thus far has never been included in any molecular study – as sistergroup to the remaining genera; (3) the monophyly of the Nandidae + Badidae and their inclusion into a larger monophyletic group – along with the Pristolepididae, Anabantoidei and Channoidei – comprising the Labyrinthici sensu Rosen & Patterson. We also review the morphological and molecular evidence for both the conflicting placement of Pristolepis and the putative sistergroup relationship between the labyrinth fishes (Anabantoidei) and snakeheads (Channoidei).  相似文献   

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Recent investigations in the upper Río Huallaga in Peru revealed the presence of an intriguing species of the Loricariinae. To characterize and place this species within the evolutionary tree of the subfamily, a molecular phylogeny of this group was inferred based on the 12S and 16S mitochondrial genes and the nuclear gene F-reticulon4. The phylogeny indicated that this distinctive species was a member of the subtribe Loricariina. Given its phylogenetic placement, and its unusual morphology, this species is described as a new genus and new species of Loricariinae: Fonchiiloricaria nanodon. This new taxon is diagnosed by usually possessing one to three premaxillary teeth that are greatly reduced; lips with globular papillae on the surface; the distal margin of lower lip bearing short, triangular filaments; the premaxilla greatly reduced; the abdomen completely covered by plates, with the plates between lateral abdominal plates small and rhombic; a caudal fin with 14 rays; the orbital notch absent; five lateral series of plates; dorsal-fin spinelet absent; preanal plate present, large and solid, and of irregular, polygonal shape, the caudal peduncle becoming more compressed posteriorly for the last seven to 10 plates.  相似文献   

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