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Molecular approaches for identifying aquatic macroinvertebrate species are increasingly being used but there is ongoing debate about the number of DNA markers needed to differentiate species accurately. Here, we use two mitochondrial genes (cytochrome oxidase I, cytochrome b) and a nuclear gene (carbamoylphosphate synthetase) to differentiate species variation within the taxonomically challenging chironomid genus Procladius from southern Australia, a genus which is important for pollution monitoring. The mitochondrial genes indicated cryptic species that were subsequently linked to morphological variation at the larval and pupal stage. Two species previously described based on morphological criteria were linked to molecular markers, and there was evidence for additional cryptic species. Each genetic marker provided different information, highlighting the importance of considering multiple genes when dissecting taxonomically difficult groups, particularly those used in pollution monitoring.  相似文献   

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Species level taxonomy and phylogeographical distribution patterns in the freshwater rhodophyte Sirodotia are resolved through phylogenetic inferences based on rbcL and cox2–3 sequence data. Previous studies focused on the taxonomy of specific Sirodotia species or the distributions across a limited geographical region. Our molecular phylogenies included samples attributable to five recognized Sirodotia species and include collections from Australia, Brazil, Costa Rica, Canada, Finland, Mexico, New Zealand, South Africa and the United States. Both rbcL and cox2–3 phylogenies inferred S. suecica, S. tenuissima and S. goebelii as a monophyletic group with little sequence divergence. This result supports the synonymy of S. tenuissima and S. goebelii with S. suecica (the species name with priority). Within this clade, samples collected from Australia and New Zealand formed a monophyletic group with no other discernible phylogeographical patterns within S. suecica. This result seems to be somewhat unusual in the Batrachospermales, as other species have shown greater genetic variation among geographically distant locations. As in previous studies, S. huillensis and S. delicatula were inferred as a separate species based on the rbcL phylogeny, supporting the current taxonomy. A specimen of S. aff. huillensis from South Africa, may represent a new species but further research is necessary before it can be designated as such.  相似文献   

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A critical reassessment of the morphological features of two closely related red algal genera,Grateloupia C.Agardh and Sinotubimorpha W.X.Li & Z.F.Ding (Halymeniaceae),pointed out that members of the t...  相似文献   

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Chironius is one of the most speciose genera of the South American colubrid snakes. Although the genus represents a well‐known radiation of diurnal racers, its monophyly, affinities with other Neotropical colubrid genera, and intrageneric relationships are open questions. Here, we present a phylogenetic analysis of Chironius based on a data matrix that combines one nuclear (c‐mos) and two mitochondrial (12S and 16S rRNA) genes with 37 morphological characters derived from scutellation, skull, and hemipenial features. Phylogenetic relationships were inferred using maximum parsimony (MP) and maximum likelihood (ML). Our combined morphological and molecular analyses strongly support the monophyly of the genus Chironius and its sister‐group relationship with a clade formed by the genera Dendrophidion and Drymobius. Phylogenetic relationships within the genus Chironius is still controversial, although five clades are retrieved with medium to strong support. © 2014 The Linnean Society of London  相似文献   

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Species of the genus Sparassis in East Asia were investigated using morphology and DNA sequences data. Phylogenetic analyses inferred from sequences of the internal transcribed spacer (ITS), the nuclear gene coding for the ribosomal large subunit (nLSU) and partial gene coding RNA polymerase subunit II (rpb2) strongly supported lineages corresponding to morphological features. Three taxa, S. subalpina, S. cystidiosa f. flabelliformis and S. latifolia were recognized from East Asia, and the former two taxa are new to science. The occurrence of S. latifolia in Japan and in the Russian Far East was confirmed. Geographical divergences of Sparassis in the Holarctic were observed. Most species have relatively narrow distribution ranges, and taxa with intercontinental distributions were not detected. Divergence of species in the Northern Hemisphere in different clades appears to have taken place at different times: the S. latifolia-crispa-radicata species complex appears to have undergone a recent radiation, while the S. subalpina-brevipes-spathularia species complex represents a relatively ancient speciation.  相似文献   

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Schizachyrium (Poaceae, Andropogoneae) includes about 60 species distributed in tropical and subtropical regions of the world. In all recent molecular phylogenies of Andropogoneae, representatives of Schizachyrium appear closely related to Andropogon species. The objective of this study was to contribute to the delimitation of Schizachyrium. We performed a phylogenetic study including 38 taxa (>63%) of Schizachyrium, along with representatives of related genera, mainly of Andropogon, yielding a total of 49 taxa. This is the first phylogenetic analysis to include the type species of Schizachyrium, S. condensatum. DNA sequences of two plastid markers (ndhF and trnL-F) were analyzed under Bayesian methods. The results indicate that Schizachyrium is not monophyletic: 26 of the 38 Schizachyrium taxa analyzed are placed in a Schizachyrium s.s. clade that includes the type species of the genus, while 10 taxa are related to Andropogon species and two other species, S. delavayi (from China and India) and S. jeffreysii (from Africa), appear clearly separated. Additionally, 58 morphological characters (41 qualitative and 17 quantitative) were scored for the same 49 taxa and analyzed under the parsimony criterion. Character optimizations showed that (i) the reduced pedicellate spikelets, (ii) with lower glume less than or equal to 0.5 mm wide, (iii) awned, and (iv) without lemma and palea support the Schizachyrium s.s. clade. We propose these four characters as diagnostic features for the delimitation of Schizachyrium s.s.  相似文献   

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Specimens of Codium fragile (Suringar) Hariot ssp. tomentosoides were collected from 9 sites in New England, and Long Island, New York at intervals throughout the years 1999-2003. Segments were removed from the thalli and chopped into fine fragments, mostly individual utricles and medullary filaments. Fragments were incubated in enriched seawater in dim light at 15C, 12:12 LD. Within 2–3 days, in almost all cases (more than 300) motile cells formed in many of the utricles and filaments. These were 10–15 micrometer elongated biflagellate heterokont cells. They appeared to consume the chloroplasts, and within 24 hours were reduced to colorless cells, about 5 micrometers long. These cells are unable to grow in Codium chloroplast suspensions. They appear to be always associated with Codium thalli, despite attempts to clean the thalli, and were never seen in utricles or filaments of intact plants. Their ultrastructure is under investigation and will be reported on here.  相似文献   

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A critical reassessment of the morphological features of two closely related red algal genera, Grateloupia C. Agardh and Prionitis J. Agardh (Halymeniaceae), shows that members of the two genera share very similar reproductive (including the Grateloupia‐type auxiliary‐cell ampullae) and vegetative characters. Diagnostic features hitherto used for distinguishing these two genera, the texture of blades (lubricous to leathery in Grateloupia vs cartilaginous in Prionitis) and the position of reproductive structures (scattered over the entire blade in Grateloupia vs confined to particular portions of the blade in Prionitis), are continuous across some 75 species of both genera, thus making it difficult to draw a clear‐cut distinction between the two genera. In ribulose‐1,5‐bisphosphate carboxylase/oxygenase gene (rbcL) sequence analyses, the species of Grateloupia and Prionitis, including the two generitypes, constitute a large monophyletic clade in the Halymeniaceae. It is therefore proposed that Prionitis be included in the synonymy under Grateloupia and the appropriate combinations are proposed.  相似文献   

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G. Mura  B. Brecciaroli 《Hydrobiologia》2004,520(1-3):179-183
Doubts have been raised about the use of morphological characters as criteria for species separation within the genus Artemia because of their relative validity. The characters considered to date, i.e. morphology of the frontal knobs of the male and the presence/absence of a spine-like projection on the basal part of the penis, are only partly efficacious, since they allow us to reliably distinguish only the Mediterranean species, Artemia salina, from the other bisexual species. While A. salina is characterized by subconical frontal knobs and the absence of the spine-like projection, the other species present subspherical frontal knobs and the spine-like projections. There is no information about the aspect of the frontal knobs in the Asian bisexual species. The aim of the present study is to clarify the situation by means of SEM observations of characters not considered in detail (ornamentation of the apical part of the spine-like projections) and by examination of the frontal knobs in the Asian species, which were not described at the time of the first studies.  相似文献   

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The pentastomid Raillietiella namibiensis n. sp., from the lungs of the agamid lizards Agama aculeata aculeata and A. planiceps planiceps taken at Windhoek, Namibia, is described. The type-series comprised 14 mature female and 9 mature males specimens, all with bluntly-rounded tips to the posterior hooks. The flared, rounded base of the male copulatory spicule was furnished with a knobbly extension projecting towards the mid-ventral line, a feature known only in two other species: Raillietiella mabuiae from Mabuya sulcata in Namibia and an as yet unnamed raillietiellid from M. homalocephala from Kenya. Significant differences in annulus number, and in the dimensions of the hooks and copulatory spicules, separate the latter species from R. namibiensis. However, the holotype female of R. mabuiae was immature and therefore of little diagnostic value, whereas the single paratype male possesses an identical spicule to R. namibiensis n. sp., but a larger hook with a much longer barb. The latter difference was sufficiently great (148 vs 108 m, range 95–115, in R. namibiensis) to justify the recognition of a new species.  相似文献   

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Combining a molecular phylogeny and morphological data, we discovered a new species of Osornophryne from the Amazonian slope of the Ecuadorian Andes. Morphologically, the new taxon is distinguished from all others species in Osornophryne by having the Toes IV and V longer than Toes I-III, a short and rounded snout with a small rostral papilla, and conical pustules on flanks. The new species previously was confused with Osornophryne guacamayo. A taxonomic key is provided for all known species of Osornophryne.  相似文献   

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The expression of morphological disparity within a clade is related to its history and to the environmental parameters within which it develops. Recent developments in geometric morphometries allow quantitative estimation of morphological disparity, and facilitate comparisons with genetic data intended to provide phylogenetic information. Such comparisons were made between two sets of ground beetle species from regions that differ biogeographically and environmentally: 12 post-glacial reinvading species from NE France; and 15 Japanese species less likely to be affected by the Pleistocene glacial events. Genetic relationships were inferred from mitochondrial DNA (ND5 gene). Morphological divergences among the species were analysed using Procrustes ver. 2.0, based on 64 landmarks (generalized analyses and computation of additive distance trees). The established morphospaces indicate distinct disparity patterns in France and Japan, even though the genetic data show that neither of the two sets arc monophyletic, and that they are in fact intermixed in the same clade. This discrepancy is partly related to the presence of extreme (elongated) morphologies in the Japanese set. But the stronger disparity observed amongjapanese species does not correspond to greater genetic differences. Those extreme morphologies appear to be related to the degree of endemicity of the species. The differences between the French and Japanese morphological patterns are discussed in the context of possible geographic factors and climatic changes during the Pleistocene.  相似文献   

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This report describes the finding of Reighardia sp. (Pentastomida) infecting the air sac of two Belcher's gulls (Larus belcheri) found dead on the beaches of Pucusana, a district in southern Lima, Peru. Three pentastomes were collected from two Belcher's gulls. Then, they were morphologically and molecular analyzed. Molecular characterization of the parasite was achieved by amplifying a fragment of the small subunit ribosomal RNA gene (SSU rRNA). Based on both morphological and molecular data the pentastomes were identified as pentastomes of the genus Reighardia. This is the first report showing that the Belcher's gull is a new natural definitive host for this pentastome.  相似文献   

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孙琴  刘小勇  王前  罗元明  王雪薇 《微生物学报》2012,52(10):1203-1209
【目的】毛壳属真菌的子囊果毛形态曾是重要的分类性状,但因容易发生变异,在现代毛壳属的分类中它们的分类学价值受到质疑。印度毛壳(Chaetomium indicum)和绳生毛壳(Chaetomium funicola)是2个依据子囊果毛形态差异定义的物种,本研究旨在从蛋白表达谱水平认识这2个种的差异及其子囊果毛的变异性,同时探讨蛋白表达谱在真菌分类中的应用价值。【方法】通过形态学观察获得印度毛壳和绳生毛壳典型菌株和子囊果毛形态变异菌株,利用双向电泳技术对典型菌株和变异菌株的蛋白表达谱进行分析和比较。【结果】双向电泳(2DE)图谱特征反映出印度毛壳和绳生毛壳之间的蛋白表达谱差异明显。根据Neighbor-joining(NJ)算法生成的系统发育树进一步显示印度毛壳和绳生毛壳分别聚在2个不同分支,即同一种的典型菌株和变异菌株聚在一起。【结论】依据子囊果毛形态特征和种特异性的蛋白表达谱特征对印度毛壳和绳生毛壳的分类结果是一致的,表明子囊果毛特征仍然是毛壳属真菌分类的重要指标。  相似文献   

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