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1.
We used ITS and trnL sequence data, analyzed separately and combined by MP, to explore species relationships and concepts in Trema (Celtidaceae), a pantropical genus of pioneer trees. Whether Trema is monophyletic or includes Parasponia is still unresolved. Three clades within Trema received moderate to high support, one from the New World and two from the Old World, but their relationships were not resolved. In the New World, specimens of T. micrantha formed two groups consistent with endocarp morphology. Group I, with smaller brown endocarps, is a highly supported clade sister to T. lamarckiana. Group II, with larger black endocarps, is poorly resolved with several subclades, including the highly supported T. integerrima clade. Both Old World clades contain Asian and African species, with three or more species in each region. Trema orientalis is not monophyletic: specimens from Africa formed a highly supported clade sister to T. africana, while those from Asia were sister to T. aspera from Australia.  相似文献   

2.
To more confidently assess phylogenetic relationships among astome ciliates, we obtained small subunit (SSU) rRNA sequences from nine species distributed in six genera and three families: Almophrya bivacuolata, Eudrilophrya complanata, Metaracoelophrya sp. 1, Metaracoelophrya sp. 2, Metaracoelophrya intermedia, Metaradiophrya sp., Njinella prolifera, Paraclausilocola constricta n. gen., n. sp., and Paraclausilocola elongata n. sp. The two new species in the proposed new clausilocolid genus Paraclausilocola n. gen. are astomes with no attachment apparatus, two files of contractile vacuoles, and an arc-like anterior suture that has differentiations of thigmotactic ciliature on the anterior ends of the left kineties of the upper surface. Phylogenetic analyses were undertaken using neighbor-joining, Bayesian inference, maximum likelihood, and maximum parsimony. The nine species of astomes formed a strongly supported clade, showing the subclass Astomatia to be monophyletic and a weakly supported sister clade to the scuticociliates. There were two strongly supported clades within the astomes. However, genera assigned to the same family were found in different clades, and genera assigned to the same order were found in both clades. Thus, astome taxa appear to be paraphyletic when morphology is used to assign species to genera.  相似文献   

3.
The placement of a recently discovered South American monotypic genus,Pseudomonotes tropenbosii, in subfam.Monotoideae (Dipterocarpaceae) extends the geographical range of the subfamily from Africa to the Neotropics. Although morphological and anatomical evidence suggest similarities betweenPseudomonotes andMonotes, the close alliance of these two genera was questionable due to their disjunct distribution and a lack of phylogenetic analysis. In the present study, we reconstructed the phylogeny ofPseudomonotes and other putatively related taxa usingrbcL sequence data. The analysis ofrbcL sequences of 20 taxa belonging to 15 genera and eight families recovered a single most parsimonious tree. The genusSarcolaena (Sarcolaenaceae) formed a clade sister to the monophyleticDipterocarpaceae clade.Monotes andPseudomonotes formed a strongly supported group, sister to the monophyletic clade withPakaraimaea and the remaining Asiatic dipterocarp species studied. The study strongly supports the placement ofPseudomonotes within subfam.Monotoideae of theDipterocarpaceae.  相似文献   

4.
Phylogenetic relationships, limits of species, and genera within Lycoperdaceae, were inferred by use of ITS and LSU nu-rDNA sequence data. Lycoperdaceae was confirmed as monophyletic, and Mycenastrum corium as a sister taxon to the ingroup. Four major clades were identified and received weak to moderate support and correspond with the genera Lycoperdon, Bovista, Calvatia, and Disciseda. The Lycoperdon clade includes species from Lycoperdon, Vascellum, Morganella, Handkea, Bovistella, and Calvatia. The structure within the Lycoperdon clade is unresolved and several clades are more or less unsupported, which suggests treating the supported Lycoperdon clade as the genus Lycoperdon. L. nigrescens and L. caudatum occur on single branches and their phylogenetic positions could not be resolved. The phylogenetic analyses identified 31 species of Lycoperdon, 11 species of Bovista, six species of Calvatia, and two species of Disciseda. In Lycoperdon three new species were recognized. A new species closely related to B. limosa is identified and discussed. A classification of Lycoperdaceae is proposed based on the results of the phylogenetic analyses. Morphological characters of species within and among identified clades are discussed.  相似文献   

5.
Phylogenetic relationships of seven Haptoglossa isolates were analyzed by using mitochondrial COII amino acid sequences with a data set of 34 peronosporomycetes. Haptoglossa isolates formed a single clade and appeared to be basal to the clade consisting of all other peronosporomycetes. The Haptoglossa clade was divided into two subclades: one clade consisted of five aplanosporic isolates and the other included one aplanosporic and one zoosporic isolate. These results indicate that the genus Haptoglossa is monophyletic, and patterns of infection cell formation reflect more the phylogenetic relationship between the species than patterns of sporogenesis.  相似文献   

6.
Phylogenetic relationships of seven isolates of the genus Haptoglossa parasitic on terrestrial nematodes within the Peronosporomycetes were analyzed using 18S rDNA sequence data with 21 peronosporomycetes, 2 marine stramenopilous flagellates, and 2 hyphochytridiomycetes. The marine stramenopilous flagellates and hyphochytridiomycetes were used as the outgroup. All Haptoglossa isolates formed a monophyletic clade and clustered with the marine genus Eurychasma. The clade of Haptoglossa and Eurychasma formed a sister-group to the clade that consisted of all other peronosporomycetes. These results suggest that the genus Haptoglossa and other terrestrial peronosporomycetes included in the two subclasses, the Saprolegniomycetidae and the Peronosporomycetidae, might have originally adapted to the terrestrial environment individually. In the maximum-likelihood (ML) analysis, the Haptoglossa clade was divided into three subclades, one aplanosporic species clade and two zoosporic species clades. Phylogenetic analyses of combined 18S rDNA and cox2 genes among five species of Haptoglossa supported the results of the ML analysis using 18S rDNA and suggested that zoosporic species may be separated into two lineages. This topology of the analysis may suggest that aplanosporic species diverged from zoosporic species.  相似文献   

7.
Polystichum is one of the largest and most taxonomically complex fern genera in China. The evolutionary relationships of Chinese Polystichum and related genera, and the relationship between our Polystichum phylogeny and ecogeographic distribution, were tested by the use of DNA sequence data. Fifty-one species of Polystichum and 21 species in allied genera were sequenced for the plastid intergenic spacers rps4-trnS and trnL-F. Maximum parsimony and Bayesian phylogenetic analyses of both individual and combined data sets showed that Chinese Polystichum as commonly recognized was paraphyletic: one clade (the CCPC clade) included Cyrtomidictyum lepidocaulon, two Cyrtogonellum species, three Cyrtomium species, and a small number of Polystichum species usually occurring on limestone. A second clade, Polystichum sensu stricto, included the remainder of the Polystichum species; these often occur on non-limestone substrates. The remaining Cyrtomium species formed the third clade. Three subclades resolved within Polystichum sensu stricto (s.s.) clade do not correspond with recent sectional classifications, and we outline the issues relevant to a new classification for the genus. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

8.
The relationship between Litsea and related genera is currently unclear. Previous molecular studies on these taxa using cpDNA and nrITS were unable to produce well-resolved phylogenetic trees. In this study, we explored the potential of the rpb2 gene as a source of molecular information to better resolve the phylogenetic analysis. Although rpb2 was believed to be a single-copy gene, our cloning results showed that most species examined possessed several copies of these sequences. However, the genetic distance among copies from any one species was low, and these copies always formed monophyletic groups in our molecular trees. Our phylogenetic analyses of rpb2 data resulted in better resolved tree topologies compared to those based on cpDNA or nrITS data. Our results show that monophyly of the genus Litsea is supported only for section Litsea. As a genus, Litsea was shown to be polyphyletic. The genera Actinodaphne and Neolitsea were resolved as monophyletic groups in all analyses. They were also shown to be sisters and closer to the genus Lindera than to the genus Litsea. Our results also revealed that the genus Lindera is not a monophyletic group.  相似文献   

9.
Four strains belonging to the Peronosporomycetes (formerly Oomycetes) were isolated from white nodules found on the mantle of three species of abalone. In artificial seawater, the four isolates formed fragments such as in the genus Haliphthoros, but the protoplasm constriction was weaker, and fragments were longer, with smaller spaces between them, than those of Haliphthoros. The four strains form one or more discharge tubes from each zoosporangium. The four strains were similar, but not identical, to the genus Haliphthoros based on morphological characteristics. As a result, the four isolates were classified in a new genus and species, Halioticida noduliformans gen. et sp. nov. Phylogenetic analysis of the D1/D2 region of the large subunit ribosomal RNA gene (LSU rDNA) was performed, and the four isolates showed 100%–99.8% concordance. In the phylogenetic tree, the four isolates were not classified in the subclass Peronosporomycetidae, Saprolegniomycetidae, or Rhipidiomycetidae. However, the four isolates formed a new clade with genera Haliphthoros and Halocrusticida in Peronosporomycetes. Within this new clade, the four isolates, Haliphthoros spp. and Halocrusticida spp., were grouped in their respective independent subclades. These results showed that these were the new genus and species from the morphological characteristics.  相似文献   

10.
The genus Ulocladium represents phaeodictyosporic Hyphomycetes that produce conidia that are essentially obovoid in shape. Previous molecular studies that included Ulocladium and related taxa in Alternaria, Embellisia, and Stemphylium revealed a conflict between morphology and phylogeny, and Ulocladium was supported as polyphyletic with a paraphyletic core group. Moreover, the genus consistently resolved within a larger Alternaria/Ulocladium clade, resulting in paraphyly of Alternaria and questions as to the taxonomic status of Ulocladium. In the present study, 13 Ulocladium species and three genetic loci were included for a more comprehensive systematic analysis of the genus than had previously been conducted. Total genomic DNA was extracted from representative taxa and sequences were determined for the nuclear internal transcribed spacer region, including the 5.8S rDNA gene, and the protein-coding genes glyceraldehyde-3-phosphate dehydrogenase and Alt a1. Subsequent phylogenetic analyses based on maximum parsimony and Bayesian methods included related Alternaria, Embellisia, and Stemphylium spp. Results supported previous findings of polyphyletic and paraphyletic relationships of Ulocladium among other taxa. Ten Ulocladium species clustered into a core Ulocladium clade and all taxa possessed the key diagnostic feature of Ulocladium, namely, conidia essentially obovoid in shape. However, A. cheiranthi and E. indefessa also clustered within this group with high bootstrap support but did not posses this diagnostic feature. This paraphyletic clade resolved basal to the core Alternaria clade with high bootstrap support, unlike previous studies in which its position was imbedded within the primary Alternaria clade. Thus, the status of the genus as an independent lineage and a unique taxon is strongly supported. As previously reported, U. alternariae and U. oudemansii, which posses the key conidium characteristics of Ulocladium, clustered as a separate clade sister to the core Ulocladium clade. Further studies are necessary to determine if these taxa represent an independent lineage or share a common ancestor with other Ulocladium species. Obovoid conidia were poorly represented in the isolate of U. lanuginosum that was included in these analyses (the only U. lanuginosum isolate currently available), and the isolate resolved as A. radicina based upon all three loci sequenced. Based upon these data and the origin of the isolate, which was originally deposited as A. malvae, a reassessment of its identity is supported.  相似文献   

11.
A phylogenetic analysis of Euphorbiaceae sensu stricto is presented using sequences from rbcL, atpB, matK and 18S rDNA from 85 species and 83 genera. The combined analysis of four molecular markers resulted in only one most parsimonious tree and also generated new supported clades, which include Euphorbioideae + Acalyphoideae s.s., subclades A2 + A3, subclades A5 + A6 and a clade uniting subclades A2–A8 within Acalyphoideae s.s. A palisadal exotegmen is a possible synapomorphy for all the Euphorbiaceae, except for the subfamily Peroideae. The presence of vascular bundles in the inner integument and a thick inner integument were shown to be synapomorphies for the clade of inaperturate and articulated crotonoids and for the large clade of Euphorbioideae, Acalyphoideae s.s., inaperturate and articulated crotonoids, respectively. Characters of the aril and vascular bundles in the outer integument are discussed. The selected embryological characters were seen to be highly correlated with the molecular phylogeny. When the results of molecular phylogenetic analysis of a previous study and this study were adjusted along with the selected embryological characters, all clades within Euphorbiaceae were supported except for a clade comprising Euphorbioideae + Acalyphoideae s.s. + inaperturate crotonoids + articulated crotonoids + Adenoclineae s.l. and a clade uniting subclades A4–A8 within Acalyphoideae s.s. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

12.
Recent collections and the type specimen of Marasmiellus juniperinus, the type species of the genus, were examined. Phylogenetic placement, based on ribosomal large subunit (LSU) and internally transcribed spacer (ITS) sequences, is within the lentinuloid clade, nested among Gymnopus taxa. This placement dictates genus name usage and phylogenetic position of other putative species of Marasmiellus. The mating system is tetrapolar.  相似文献   

13.
The genus Hesperodiaptomus Light, 1938, one of the most diverse groups of freshwater copepods that occur in North and Central America, plays a major role in the food webs of the alpine freshwater communities. Phylogenetic relationships of these taxa remain poorly understood due to difficulties in obtaining reliable morphological characters for phylogenetic analyses. To understand the phylogenetic relationships within this group, we reconstructed a partial phylogeny of the genus Hesperodiaptomus based on nuclear ribosomal gene sequences. Phylogenetic analyses based upon the taxa examined supported the monophyly the genus and revealed two clades. The eiseni clade comprised species that are morphologically similar to Hesperodiaptomus eiseni (Lilljeborg, 1889), and the shoshone clade included species morphologically similar to Hesperodiaptomus shoshone (S.A. Forbes, 1882). The two groups can be distinguished by a modification of the right basis, the arrangement of spinules on the distal pad of the second exopod, and the degree of presence the inner lamellar expansion of the right coxa. Handling editor: P. Spaak  相似文献   

14.
Based on extensive phenetic analyses, bats of the genus Myotis have been classically subdivided into four major subgenera each of which comprise many species with similar morphological and ecological adaptations. Each subgenus thus corresponds to a distinct “ecomorph” encompassing bat species exploiting their environment in a similar fashion. As three of these subgenera are cosmopolitan, regional species assemblages of Myotis usually include sympatric representatives of each ecomorph. If species within these ecomorphs are monophyletic, such assemblages would suggest extensive secondary dispersal across geographic areas. Conversely, these ecomorphological adaptations may have evolved independently through deterministic processes, such as adaptive radiation. In this case, phylogenetic reconstructions are not expected to sort species of the same ecomorph into monophyletic clades. To test these predictions, we reconstructed the phylogenetic history of 13 American, 11 Palaearctic, and 6 other Myotis species, using sequence data obtained from nearly 2 kb of mitochondrial genes (cytochrome b and nd1). Separate or combined analyses of these sequences clearly demonstrate the existence of several pairs of morphologically very similar species (i.e., sibling species) which are phylogenetically not closely related. None of the three tested subgenera constitute monophyletic units. For instance, Nearctic and Neotropical species currently classified into the three subgenera were clustered in a single, well-supported monophyletic clade. These species thus evolved independently of their ecological equivalents from the Palaearctic region. Independent adaptive radiations among species of the genus Myotis therefore produced strikingly similar evolutionary solutions in different parts of the world. Furthermore, all phylogenetic reconstructions based on mtDNA strongly supported the existence of an unsuspected monophyletic clade which included all assayed New World species plus M. brandtii (from the Palaearctic Region). This “American” clade thus radiated into a morphologically diverse species assemblage which evolved after the first Myotis species colonized the Americas. Molecular reconstructions support paleontological evidence that species of the genus Myotis had a burst of diversification during the late Miocene–early Pliocene epoch.  相似文献   

15.
张余  龚洵  冯秀彦 《广西植物》2021,41(1):114-122
富民枳(Poncirus polyandra)属于芸香科(Rutaceae)枳属(Poncirus Raf.).自发表以来,分类地位一直备受争议,其中在Flora of China中认为富民枳为柑橘杂交种(Poncirus polyandra),把枳属归并于柑橘属(Citrus).该研究选取枳属的富民枳、枳(Ponci...  相似文献   

16.
分子系统学研究将传统梧桐科与锦葵科、木棉科和椴树科合并为广义锦葵科,并进一步分为9个亚科.然而,9个亚科之间的关系尚未完全明确,且梧桐亚科内的属间关系也未得到解决.为了明确梧桐亚科在锦葵科中的系统发育位置,厘清梧桐亚科内部属间系统发育关系,该研究对锦葵科8个亚科进行取样,共选取55个样本,基于叶绿体基因组数据,采用最大...  相似文献   

17.
The about 31 species of Fosterella L.B. Sm. (Bromeliaceae) are terrestrial herbs with a centre of diversity in the central South American Andes. To resolve infra- and intergeneric relationships among Fosterella and their putative allies, we conducted a phylogenetic analysis based on sequence data from four chloroplast DNA regions (matK gene, rps16 intron, atpB-rbcL and psbB-psbH intergenic spacers). Sequences were generated for 96 accessions corresponding to 60 species from 18 genera. Among these, 57 accessions represented 22 of the 31 recognized Fosterella species and one undescribed morphospecies. Maximum parsimony and Bayesian inference methods yielded well-resolved phylogenies. The monophyly of Fosterella was strongly supported, as was its sister relationship with a clade comprising Deuterocohnia, Dyckia and Encholirium. Six distinct evolutionary lineages were distinguished within Fosterella. Character mapping indicated that parallel evolution of identical character states is common in the genus. Relationships between species and lineages are discussed in the context of morphological, ecological and biogeographical data as well as the results of a previous amplified fragment length polymorphism (AFLP) study.  相似文献   

18.
Species in the genus Castanea are widely distributed in the deciduous forests of the Northern Hemisphere from Asia to Europe and North America. They show floristic similarity but differences in chestnut blight resistance especially among eastern Asian and eastern North American species. Phylogenetic analyses were conducted in this study using sequences of three chloroplast noncoding trnT-L-F regions. The trnT-L region was found to be the most variable and informative region. The highest proportion of parsimony informative sites, more and larger indels, and higher pairwise distances between taxa were obtained at trnT-L than at the other two regions. The high A+T values (74.5%) in the Castanea trnT-L region may explain the high proportion of transversions found in this region where as comparatively lower A+T values were found in the trnL intron (68.35%) and trnL-F spacer (70.07%) with relatively balanced numbers of transitions and transversions. The genus Castanea is supported as a monophyletic clade, while the section Eucastanon is paraphyletic. C. crenata is the most basal clade and sister to the remainder of the genus. The three Chinese species of Castanea are supported as a single monophyletic clade, whose sister group contains the North American and European species. There is consistent but weak support for a sister–group relationship between the North American species and European species.  相似文献   

19.
狭义蛇葡萄属(Ampelopsis s. str.)是葡萄科的落叶木质藤本植物,主要分布在北半球温带地区,特别是东亚为其重要的分布和演化中心。该研究选取了狭义蛇葡萄属15个种的37个样本,对其5个叶绿体基因片段(trnL-F、rps16、psbA-trnH、atpB-rbcL和trnK-petN)和2个核基因标记(ITS和GAI1)进行了分子测序;利用测序获得的分子数据探讨属内的系统发生关系,叶的性状演化以及生物地理起源演化。结果表明:(1)狭义蛇葡萄属是一个单系类群,属内东亚地区的物种聚成一支。(2)叶绿体基因数据分析结果表明,狭义蛇葡萄属东亚支系分为两支系,这两支系的分布范围大致与东亚植物区系的中国-日本森林和中国-喜马拉雅森林亚区范围相一致。(3)形态演化分析表明,掌状复叶为祖征,叶形态性状存在多次的独立起源和演化,其变化与系统进化没有明显的关系。(4)生物地理分析结果表明,狭义蛇葡萄属起源于北美,渐新世晚期至中新世早期迁移扩散至欧洲,中新世中期随着全球气温回暖迁移至东亚,并进一步在东亚地区快速分化形成多样化中心,这可能与中新世时期的气候温暖、受第四纪冰川影响较少以及东亚地区复杂...  相似文献   

20.
The Vittiaceae are a small family of aquatic mosses that are defined based on gametophytic traits whose interpretation has led to conflicting taxonomic arrangements. Phylogenetic analyses of two cpDNA regions, trnL-trnF and atpB-rbcL, indicate that Vittia is nested within the Amblystegiaceae s. str., suggesting that the family Vittiaceae should not be recognized. Platylomella lescurii appears nested within the Thuidiaceae/Leskeaceae. This suggests that the series of character states shared by Vittia and Platylomella, including a differentiated leaf border, short laminal cells, stiff stems, and a thick costa, are convergent features that arose independently in unrelated lineages of aquatic Hypnales. Within the Amblystegiaceae, phylogenetic analyses of the two cpDNA regions combined with ITS sequence data show that Hypnobartlettia, Vittia elimbata spec. nov., V. pachyloma, and V. salina, despite their strong morphological similarity to aquatic Amblystegium species, form a clade that is sister to the Drepanocladus/Pseudo-calliergon complex. This combined clade is unresolved at a polytomy that includes Amblystegium serpens and a clade including all the other Amblystegium species. The occurrence of A. serpens outside the strongly supported clade including other Amblystegium species suggests that A. serpens may be better accommodated in a distinct genus. Amblystegium serpens is the type species of Amblystegium and thus retains the name. The other species are accommodated in their own genus, Hygroamblystegium, including H. fluviatile, H. humile comb. nov., H. noterophyllum, H. tenax, and H. varium.  相似文献   

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