首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
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   

2.
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   

3.
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   

4.
The aim of the present paper is to explore the role of the character in phylogenetic systematics. I argue that too much emphasis is put on particular characters rather than congruence both in the choice of phylogenetic hypotheses and in taxonomic decisions. This means that the logical priority of the tree over the characters is neglected. To a large extent, this is a result of not paying enough attention to the individuality thesis which states that clades are historical individuals and hence contingent in nature.  相似文献   

5.
An adverse consequence of applying morphology‐based taxonomic systems to catalog cyanobacteria, which generally are limited in the number of available morphological characters, is a fundamental underestimation of natural biodiversity. In this study, we further dissect the polyphyletic cyanobacterial genus Lyngbya and delineate the new genus Okeania gen. nov. Okeania is a tropical and subtropical, globally distributed marine group abundant in the shallow‐water benthos. Members of Okeania are of considerable ecological and biomedical importance because specimens within this group biosynthesize biologically active secondary metabolites and are known to form blooms in coastal benthic environments. Herein, we describe five species of the genus Okeania: Ohirsuta (type species of the genus), Oplumata, Olorea, Oerythroflocculosa, and O. comitata, under the provisions of the International Code of Nomenclature for Algae, Fungi, and Plants. All five Okeania species were morphologically, phylogenetically, and chemically distinct. This investigation provides a classification system that is able to identify Okeania spp. and predict their production of bioactive secondary metabolites.  相似文献   

6.
7.
The genus Phora (Diptera, Phoridae) includes more than 50 species widely distributed in temperate regions of Eurasia and Africa. Taxonomic identification of most species is based upon the morphology of the male hypopygium: hence for many species, including the type species of the genus, females are unknown. We used mitochondrial 16S ribosomal RNA sequences to match males with previously unidentified females from Phora atra , P. stictica , and P. holosericea . We then identified morphological characters that allow identification of females of P. atra and P. stictica without recourse to DNA sequencing. Our results show that small scale sequencing can aid in the development of taxonomic characters for use in the field to identify previously cryptic females. This iterative method of identifying populations genetically followed by re-examination of morphology should allow development of better keys for rapid identification of heretofore cryptic populations of insects. We also found that sequences from individual of P. holosericea from Cambridge, England and Malakhovka, Russia, were more similar to each other than to sequences from a conspecific fly also collected in Cambridge. This result suggests that there is previously un-suspected population structuring in this species.  © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77 , 267–273.  相似文献   

8.
The species-rich genus Polyalthia has previously been shown to be highly polyphyletic, with species represented in at least five different clades. The Polyalthia species that are associated with Marsypopetalum and Trivalvaria (as revealed either by previous phylogenetic studies or inferred on the basis of comparative morphology) were included in a molecular phylogenetic study based on three chloroplast DNA regions (matK, rbcL and trnL-F). Maximum parsimony, maximum likelihood and Bayesian analyses consistently revealed that several Polyalthia species form a well-supported clade with Marsypopetalum pallidum, and that this clade is sister to Trivalvaria. Diagnostic morphological characters for the clades are re-evaluated and shown to be congruent with the molecular phylogeny. Five Polyalthia species (P. crassa, P. littoralis, P. lucida, P. modesta and P. tristis) are accordingly transferred to Marsypopetalum.  相似文献   

9.
The microfilamentous green alga Uronema curvatum is widely distributed along the western and eastern coasts of the north Atlantic Ocean where it typically grows on crustose red algae and on haptera of kelps in subtidal habitats. The placement of this marine species in a genus of freshwater Chlorophyceae had been questioned. Molecular phylogenetic analysis of nuclear-encoded small and large subunit rDNA sequences reveal that U. curvatum is closely related to the ulvophycean order Cladophorales, with which it shares a number of morphological features, including a siphonocladous level of organization and zoidangial development. The divergent phylogenetic position of U. curvatum, sister to the rest of the Cladophorales, along with a combination of distinctive morphological features, such as the absence of pyrenoids, the diminutive size of the unbranched filaments and the discoid holdfast, warrants the recognition of a separate genus, Okellya, within a new family of Cladophorales, Okellyaceae. The epiphytic Urospora microscopica from Norway, which has been allied with U. curvatum, is revealed as a member of the cladophoralean genus Chaetomorpha and is herein transferred to that genus as C. norvegica nom. nov.  相似文献   

10.
唐赛春  夏念和  林汝顺 《广西植物》2005,25(5):437-439,468,i0005
竹类果实胚体类型复杂多样,中胚轴的有无,外胚叶的存在与否,盾片是否具有裂片,第一叶折叠或卷曲为大致的划分标准。胚的类型,胚芽、胚根与盾片的关系,胚体弯曲程度,中胚轴伸长程度及盾片的大小和形态等,在不同的种中有不同的特征。首次报道了花眉竹和融安黄竹这两种竹果的胚体类型分别为P+PP和F+PP及各自的特征,并探讨其系统分类的意义,为竹类植物的系统分类补充解剖学方面的证据。  相似文献   

11.
The classifications of primates, in general, and platyrrhine primates, in particular, have been greatly revised subsequent to the rationale for taxonomic decisions shifting from one rooted in the biological species concept to one rooted solely in phylogenetic affiliations. Given the phylogenetic justification provided for revised taxonomies, the scientific validity of taxonomic distinctions can be rightly judged by the robusticity of the phylogenetic results supporting them. In this study, we empirically investigated taxonomic-sampling effects on a cladogram previously inferred from craniodental data for the woolly monkeys (Lagothrix). We conducted the study primarily through much greater sampling of species-level taxa (OTUs) after improving some character codings and under a variety of outgroup choices. The results indicate that alternative selections of species subsets from within genera produce various tree topologies. These results stand even after adjusting the character set and considering the potential role of interobserver disagreement. We conclude that specific taxon combinations, in this case, generic or species pairings, of the primary study group has a biasing effect in parsimony analysis, and that the cladistic rationale for resurrecting the Oreonax generic distinction for the yellow-tailed woolly monkey (Lagothrix flavicauda) is based on an artifact of idiosyncratic sampling within the study group below the genus level. Some recommendations to minimize the problem, which is prevalent in all cladistic analyses, are proposed.  相似文献   

12.
介绍了木霉属真菌的分类系统 ,有关木霉种系发育的分子生物学研究进展 ,以及在酶制剂、农业和环境保护中的应用概况。  相似文献   

13.
Lobophylliidae is a family‐level clade of corals within the ‘robust’ lineage of Scleractinia. It comprises species traditionally classified as Indo‐Pacific ‘mussids’, ‘faviids’, and ‘pectiniids’. Following detailed revisions of the closely related families Merulinidae, Mussidae, Montastraeidae, and Diploastraeidae, this monograph focuses on the taxonomy of Lobophylliidae. Specifically, we studied 44 of a total of 54 living lobophylliid species from all 11 genera based on an integrative analysis of colony, corallite, and subcorallite morphology with molecular sequence data. By examining coral skeletal features at three distinct levels – macromorphology, micromorphology, and microstructure – we built a morphological matrix comprising 46 characters. Data were analysed via maximum parsimony and transformed onto a robust molecular phylogeny inferred using two nuclear (histone H3 and internal transcribed spacers) and one mitochondrial (cytochrome c oxidase subunit I) DNA loci. The results suggest that micromorphological characters exhibit the lowest level of homoplasy within Lobophylliidae. Molecular and morphological trees show that Symphyllia, Parascolymia, and Australomussa should be considered junior synonyms of Lobophyllia, whereas Lobophyllia pachysepta needs to be transferred to Acanthastrea. Our analyses also lend strong support to recent revisions of Acanthastrea, which has been reorganized into five separate genera (Lobophyllia, Acanthastrea, Homophyllia, Sclerophyllia, and Micromussa), and to the establishment of Australophyllia. Cynarina and the monotypic Moseleya remain unchanged, and there are insufficient data to redefine Oxypora, Echinophyllia, and Echinomorpha. Finally, all lobophylliid genera are diagnosed under the phylogenetic classification system proposed here, which will facilitate the placement of extinct taxa on the scleractinian tree of life.  相似文献   

14.
Given the problems of species delimitation in algae using morphology or sexual compatibility, molecular data are becoming the standard for delimiting species and testing their traditional boundaries. The idea that species are separately evolving metapopulation lineages, along with theoretical progress in phylogenetic and population genetic analyses, has led to the development of new methods of species delimitation. We review these recent developments in DNA-based species delimitation methods, and discuss how they have changed and continue to change our understanding of algal species boundaries. Although single-locus approaches have proven effective for a first rapid and large-scale assessment of species diversity, species delimitation based on single gene trees falls short due to gene tree–species tree incongruence, caused by confounding processes like incomplete lineage sorting, trans-species polymorphism, hybridization and introgression. Data from unlinked loci and multi-species coalescent methods, which combine principles from phylogenetics and population genetics, may now be able to account for these complicating factors. Several of these methods also provide statistical support regarding species boundaries, which is important because speciation is a process and therefore uncertainty about precise species boundaries is inevitable in recently diverged lineages.  相似文献   

15.
Because of the poor state of knowledge of many of the gymnophthalmid genera, systematic revision is necessary to render the classification consistent with evolutionary history. To that end, I conducted a review of the species of three genera of the Cercosaurinae which appear to form a monophyletic group: Cercosaura , Pantodactylus , and Prionodactylus . Phylogenetic analysis of 61 morphological characters was conducted after specimens of all species were examined to evaluate the composition of each taxon. The phylogenetic reconstruction suggested that the genus Prionodactylus was paraphyletic. A new phylogenetic classification is proposed that synonymizes Pantodactylus and Prionodactylus with Cercosaura. Cercosaura is redefined to include 11 species and seven subspecies. A key is provided to distinguish among species.  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society, 2003, 137 , 101−115.  相似文献   

16.
Modern coral taxonomy has begun to resolve many long‐standing problems in traditional systematics stemming from its reliance on skeletal macromorphology. By integrating examinations of colony, corallite, and subcorallite morphology with the molecular sequence data that have proliferated in the last decade, many taxa spread across the scleractinian tree of life have been incorporated into a rigorous classification underpinned by greater phylogenetic understanding. This monograph focuses on one of the most challenging clades recovered to date – its disarray epitomized by the informal name ‘Bigmessidae’. This group of predominantly Indo‐Pacific species previously comprised families Merulinidae, Faviidae, Pectiniidae, and Trachyphylliidae, but in a recent study these have been incorporated within Merulinidae. We studied 84 living merulinid species by examining morphological traits at three different scales of coral skeletal structure ? macromorphology, micromorphology, and microstructure ? to construct a morphological matrix comprising 44 characters. Data were analysed via maximum parsimony and also transformed onto a robust molecular phylogeny under the parsimony and maximum likelihood criteria. Comparisons amongst morphological character types suggest that although many characters at every scale are homoplastic, some to a greater extent than others, several can aid in distinguishing genus‐level clades. Our resulting trees and character analyses form the basis of a revised classification that spans a total of 139 species contained within 24 genera. The tree topologies necessitate the synonymization of Barabattoia as Dipsastraea, and Phymastrea as Favites. Furthermore, Astrea and Coelastrea are resurrected, and one new genus, P aramontastraea Huang & Budd gen. nov. , is described. All the genera in Merulinidae, along with the monotypic Montastraeidae and Diploastraeidae, are diagnosed based on the characters examined. The integrative classification system proposed here will form the framework for more accurate biodiversity estimates and guide the taxonomic placement of extinct species. © 2014 The Linnean Society of London  相似文献   

17.
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   

18.
The proposal to implement a phylogenetic nomenclatural system governed by the PhyloCode), in which taxon names are defined by explicit reference to common descent, has met with strong criticism from some proponents of phylogenetic taxonomy (taxonomy based on the principle of common descent in which only clades and species are recognized). We examine these criticisms and find that some of the perceived problems with phylogenetic nomenclature are based on misconceptions, some are equally true of the current rank-based nomenclatural system, and some will be eliminated by implementation of the PhyloCode. Most of the criticisms are related to an overriding concern that, because the meanings of names are associated with phylogenetic pattern which is subject to change, the adoption of phylogenetic nomenclature will lead to increased instability in the content of taxa. This concern is associated with the fact that, despite the widespread adoption of the view that taxa are historical entities that are conceptualized based on ancestry, many taxonomists also conceptualize taxa based on their content. As a result, critics of phylogenetic nomenclature have argued that taxonomists should be free to emend the content of taxa without constraints imposed by nomenclatural decisions. However, in phylogenetic nomenclature the contents of taxa are determined, not by the taxonomist, but by the combination of the phylogenetic definition of the name and a phylogenetic hypothesis. Because the contents of taxa, once their names are defined, can no longer be freely modified by taxonomists, phylogenetic nomenclature is perceived as limiting taxonomic freedom. We argue that the form of taxonomic freedom inherent to phylogenetic nomenclature is appropriate to phylogenetic taxonomy in which taxa are considered historical entities that are discovered through phylogenetic analysis and are not human constructs.  相似文献   

19.
20.
中国兔属动物的分类现状和分布   总被引:3,自引:0,他引:3  
相雨  杨奇森  夏霖 《四川动物》2004,23(4):391-397
兔属 (Lepus)动物是一类广泛分布、彼此差异较小的哺乳动物 ,属于兔形目 (Lagomorpha)、兔科(Leporidae)。本文根据目前的分类现状 ,列出中国兔属种、亚种名录和分布区 ;对中国兔属动物的研究历史进行了综述 ;并针对蒙古兔、华南兔、云南兔、中亚兔和东北黑兔分类地位存在的争议进行了讨论  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号