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1.
The family Asclepiadaceae (Dicotyledones) was created by Brown in 1810 by splitting in two the family Apocynaceae of Jussieu established in 1789. The morphological characters used to make this distinction were mainly palynological, such as presence of tetrads or pollinia and number and orientation of pollinia. Those characters, still used in higher taxonomic delimitation (families, subfamilies, and tribes), are here critically reexamined and compared to a molecular phylogeny obtained with one of the more variable plastid genes (matK) of 46 species in the order Gentianales. In this molecular phylogeny, Asclepiadaceae form a monophyletic group derived from within Apocynaceae. Each of the subfamilies of Asclepiadaceae is monophyletic and based on reliable palynological characters, but palynological characters are not useful to delimit tribes of the subfamily Asclepiadoideae. Based on the molecular data, these tribes have undergone parallelisms in several reproductive traits.  相似文献   

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The Menispermaceae family contains ca. 72 genera with 450 species that are almost entirely tropical. Its phylogeny at the tribal level has never been examined using molecular data. Here we used DNA sequences of the chloroplast matK gene and trnL-F regions, and the nuclear ITS region to study the delimitation and position of the tribe Menispermeae within the family and its subtribal monophyletic groups. Family-wide phylogenetic analyses of the chloroplast data produced two strongly supported clades. The first clade contains two subclades: Coscinieae including Arcangelisia and Anamirta, and Tinosporeae sensu lato including Fibraureae, supported by morphological characters, such as traits of the cotyledon, stylar scar and embryo. The second clade consists of the tribes Menispermeae sensu DC. and Tiliacoreae Miers. All our analyses surprisingly recognized that tribe Menispermeae is not monophyletic unless tribe Tiliacoreae is included, suggesting that characters of cotyledon and stylar scar are very important for the infrafamilial classification, and that endosperm presence vs. absence was over-emphasized in traditionally tribal division of the family. Our topologies indicate a secondary loss of endosperm. The monophyly of two subtribes of the tribe Menispermeae, Stephaniinae and Cissampelinae, is supported by the cpDNA and ITS data, as well as by morphological characters, including aperture types and shapes, and colpal membrane features of pollen grains, and sepal number of male flowers. The Cocculinae was recognized as a paraphyletic group containing the remaining genera of the tribe Menispermeae.  相似文献   

4.
We used the chloroplast gene ndhF to reconstruct the phylogeny of the moonseed family (Menispermaceae), a morphologically diverse and poorly known cosmopolitan family of dioecious, primarily climbing plants. This study includes a worldwide sample of DNA sequences for 88 species representing 49 of the 70 genera of all eight traditionally recognized tribes. Phylogenetic relationships were estimated, and the Shimodaira-Hasegawa test was used to compare the likelihood of alternative phylogenetic hypotheses and to evaluate the monophyly of tribes currently in use. The monospecific Indo-Malesian Tinomiscium is sister to the remaining members of the family, within which are two major clades. Within these two clades, well-supported clades correspond to four of the eight traditionally recognized tribes, while others, such as Menispermeae, are polyphyletic. Mapping of major morphological characters on the phylogeny indicates that the crescent-shaped seed is derived from a straight seed, the tree habit has arisen multiple times, endosperm has been lost many times, but unicarpellate flowers evolved only once. Morphological synapomorphies for Menispermaceae include the presence of a condyle, a large embryo, and druplets. The phylogeny provides for the first time a detailed molecular-based assessment of relationships in Menispermaceae and clarifies our understanding of morphological diversification within the family.  相似文献   

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Abstract The phylogeny of extant Menispermaceae (Ranunculales) is reconstructed based on DNA sequences of two chloroplast genes (rbcL and atpB) from 94 species belonging to 56 genera. Fossilized endocarps represent 34 genera. The positions of these are inferred using 30 morphological characters and the molecular phylogeny as a backbone constraint. Nine of the thirteen nodes that are each dated by a fossil are used as calibration points for the estimates of molecular divergence times. BEAST is used to estimate stem age (121.2 Myr) and crown age (105.4 Myr) for Menispermaceae. This method does not require an input tree topology and can also account for rate heterogeneity among lineages. The sensitivity of these estimates to fossil constraints is then evaluated by a cross‐validation procedure. The estimated origin for Menispermaceae is dated to the mid‐Jurassic if the customary maximum age of 125 Myr for eudicots is not implemented. All constraints when used alone failed to estimate node ages in some parts of the tree. Fossils from the Palaeocene and Eocene impose strict constraints. Likewise, the use of Prototinomiscium as a dating constraint for Menispermaceae appears to be a conservative approach.  相似文献   

7.
The leaf beetle genus Trirhabda contains 26 described species from the United States and Canada, feeding on host plants from the families Asteraceae and Hydrophyllaceae. In this study, we present a phylogeny for the genus that was reconstructed from mitochondrial COI and 12S rRNA fragments, nuclear ITS2 rRNA, and morphological characters. Both parsimony and mixed-model Bayesian likelihood analyses were performed. Under both methods, the mitochondrial and nuclear partitions support the same backbone phylogeny, as do the combined data. The utility of the molecular data is contrasted with the low phylogenetic signal among morphological characters. The phylogeny was used to trace the evolution of the host-plant association in Trirhabda. The recovered phylogeny shows that although the host-plant association is phylogenetically conservative, Trirhabda experienced one shift to a distantly related host-plant family, 6 shifts between host-plant tribes, and 6 between genera within tribes. The phylogeny reveals that Trirhabda were plesiomorphically adapted to tolerate complex secondary compounds of its host plants and this adaptation is retained in Trirhabda species, as evidenced by multiple shifts from chemically simpler host plants back to the more complex host plants.  相似文献   

8.
We aim to present phylogenetic major groups within the subfamily Cyperoideae (Cyperaceae) on the basis of three molecular data sets; nuclear ribosomal internal transcribed spacer and 5.8S ribosomal RNA region, the ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit gene, and trnL intron and trnL-F intergenic spacer. Three molecular data and two combined data sets were used to obtain robust and detailed phylogenetic trees by using maximum parsimony and Bayesian inference, respectively. We analyzed 81 genera and 426 species of Cyperaceae, including Korean species. We suggest one early diverged group (EDGs), and two major clades (FAEC and SDC) within the subfamily Cyperoideae. And the clade EDGs comprises six tribes (Schoeneae, Bisboeckelereae, Sclerieae, Cryptangieae, Trilepideae, and Rhynchosporeae) at the basal nodes of Cyperoideae. The FAEC clade (posterior probability [PP]/bootstrap value [BS] = 1.00/85) comprises four tribes (Fuireneae, Abildgaardieae, Eleocharideae, Cypereae), and the SDC clade (PP/BS = 1.00/86) comprises three tribes (Scirpeae, Dulichieae, Cariceae). These three clades used for phylogenetic groups in our study will be useful for establishing the major lineage of the sedge family. The phylogeny of Korean sedges was also investigated within the whole phylogeny of Cyperaceae. The 20 genera of Korean sedges were placed in 10 tribes forming 14 clades.  相似文献   

9.
Ania Lindl. is a small genus of the tribe Collabieae subtribe Collabiinae (Orchidaceae). For the last 150 years, it has generally been treated as a synonym of Tainia Blume. In this study, we critically re-examined morphological characters that have been used to distinguish Ania from Tainia, and assessed the phylogeny of Tainia using morphological and palynological characters. Sequences of the nuclear ribosomal ITS, chloroplast trnL intron and combined DNA data sets were analysed to clarify the delimitation and the phylogeny of these groups. The morphological and palynological survey revealed a number of useful diagnostic characters which permit a clear definition of Ania, after the exclusion of a single taxonomically questionable species. Results confirmed that Ania is distinct from Tainia. Phylogenetic reconstructions based on molecular data provided the greatest resolution and produced a morphologically well differentiated clade of Ania. In addition to morphological and suggested palynological characters, the phylogenies were also supported by karyological evidence. Our results support the independent generic status of Ania. The genus name Ania is revived and re-established.  相似文献   

10.
Molecular sequences now overwhelm morphology in phylogenetic inference. Nonetheless, most molecular studies are conducted on a limited number of taxa, as DNA rarely can be analysed from old museum types or fossils. During the last 20 years, more than 150 molecular studies have challenged the current phylogenetic classification of the family Drosophilidae Rondani based on morphological characters. Most studies concerned a single genus, Drosophila Fallén, and included only few representative species from 17 out of the 78 genera of the family. Therefore, these molecular studies were unable to provide an alternative classification scheme. A supermatrix analysis of seven nuclear and one mitochondrial genes (8248 bp) for 33 genera was conducted using outgroups from one calyptrate and four ephydroid families. The Bayesian phylogeny was consistent with previous molecular studies including whole genome sequences and divided the Drosophilidae into four monophyletic clades. Morphological characters, mostly male genitalia, then were compared thoroughly between the four clades and homologous character states were identified. These states were then checked for 70 genera and a revised phylogenetic, family‐group classification for the Drosophilidae is proposed. Two genera –Cladochaeta Coquillett and Diathoneura Duda – of the tribe Cladochaetini Grimaldi are transferred to the family Ephydridae. The Drosophilidae is divided into two subfamilies: Steganinae Hendel (30 genera) and Drosophilinae Rondani (43 genera). A further two genera, Apacrochaeta Duda and Sphyrnoceps de Meijere, are incertae sedis, and Palmophila Grimaldi, is synonymized with Drosophila syn.n. The Drosophilinae is subdivided into two tribes: the re‐elevated Colocasiomyini Okada (nine genera) and Drosophilini Okada. The paraphyly of the genus Drosophila was not resolved to avoid affecting the binomina of important laboratory model species; however, its subgeneric classification was revised in light of molecular and morphological data. Three subgenera, namely Chusqueophila Brncic, Phloridosa Sturtevant and Psilodorha Okada, were synonymized with the subgenus Drosophila (Drosophila) Fallén syns.n. Among the 45 species groups and 5 species complexes of Drosophila (Drosophila), 22 groups and 1 complex were transferred to the subgenus Drosophila (Siphlodora) Patterson & Mainland and 6 groups, 2 species subgroups and 3 complexes are considered incertae sedis within the genus Drosophila. Different morphological characters provide different signals at different phylogenetic scales: thoracic characters (wing venation and presternal shape) discriminate families; grasping and erection‐related characters discriminate subfamilies to tribes; whereas phallic paraphyses, i.e. auxiliary intromittent organs, discriminate genera and Drosophila subgenera. The study shows the necessity of analysing morphological characters within a molecular phylogenetic framework to translate molecular phylogenies into taxonomically‐comprehensive classifications.  相似文献   

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The phylogeny of extant Menispermaceae (Ranunculales) is reconstructed based on DNA sequences of two chloroplast genes (rbcL and atpB) from 94 species belonging to 56 genera. Fossilized endocarps represent 34 genera. The positions of these are inferred using 30 morphological characters and the molecular phylogeny as a backbone constraint. Nine of the thirteen nodes that are each dated by a fossil are used as calibration points for the estimates of molecular divergence times. BEAST is used to estimate stem a...  相似文献   

13.
A phylogenetic study of representatives of the family Coleophoridae was conducted using a comprehensive approach, including methods of morphological and molecular genetic analyses. The existent data on the family system were compared with the results of phylogenetic analysis of the COI mitochondrial gene sequences. Four of the five studied subfamilies (Coleophorinae, Ischnophaninae, Augasminae, and Tolleophorinae) corresponded to their location on the phylogram; representatives of Metriotinae were part of Coleophorinae. According to the aggregate data from molecular phylogeny and morphology, the most numerous subfamily of casebearers, Coleophorinae, is polyphyletic within its current boundaries. The results of our analysis of COI molecular divergence does not refute the monophyly of the tribes Casignetellini, Carpochenini, Klinzigedini, Goniodomini, Casasini, and Atractulini from the subfamily Coleophorinae. The allocation of the tribes Aporipturini and Sistrophoecini within the subfamily does not correspond to the molecular data. Monophyly of the genera Ecebalia, Perygra, and Casignetella was confirmed. These genera are well isolated, which reflects the evolutionary significance of the morphological characters chosen for their taxonomic division. The boundaries of the cluster containing these genera correspond to those of the tribe Casignetellini, justifying the allocation of this tribe within the subfamily. The existence of monophyletic tribes Goniodomini (genus Goniodoma) and Carpochenini (genera Ionescumia, Carpochena, and Falkmisa) was also supported. The exceptions were the genera Kasyfia, Tollsia, and Agapalsa, whose monophyly was not confirmed by our results. The distribution of the sequences of species of these genera indicated a paraphyletic origin of Kasyfia and Tollsia and a polyphyletic origin of Agapalsa.  相似文献   

14.

Background

Revised by Bond and Platnick in 2007, the trapdoor spider genus Myrmekiaphila comprises 11 species. Species delimitation and placement within one of three species groups was based on modifications of the male copulatory device. Because a phylogeny of the group was not available these species groups might not represent monophyletic lineages; species definitions likewise were untested hypotheses. The purpose of this study is to reconstruct the phylogeny of Myrmekiaphila species using molecular data to formally test the delimitation of species and species-groups. We seek to refine a set of established systematic hypotheses by integrating across molecular and morphological data sets.

Methods and Findings

Phylogenetic analyses comprising Bayesian searches were conducted for a mtDNA matrix composed of contiguous 12S rRNA, tRNA-val, and 16S rRNA genes and a nuclear DNA matrix comprising the glutamyl and prolyl tRNA synthetase gene each consisting of 1348 and 481 bp, respectively. Separate analyses of the mitochondrial and nuclear genome data and a concatenated data set yield M. torreya and M. millerae paraphyletic with respect to M. coreyi and M. howelli and polyphyletic fluviatilis and foliata species groups.

Conclusions

Despite the perception that molecular data present a solution to a crisis in taxonomy, studies like this demonstrate the efficacy of an approach that considers data from multiple sources. A DNA barcoding approach during the species discovery process would fail to recognize at least two species (M. coreyi and M. howelli) whereas a combined approach more accurately assesses species diversity and illuminates speciation pattern and process. Concomitantly these data also demonstrate that morphological characters likewise fail in their ability to recover monophyletic species groups and result in an unnatural classification. Optimizations of these characters demonstrate a pattern of “Dollo evolution” wherein a complex character evolves only once but is lost multiple times throughout the group''s history.  相似文献   

15.
金则新  顾婧婧  李钧敏 《生态学报》2012,32(12):3849-3858
比较了濒危植物夏蜡梅(Sinocalycanthus chinensis)大明山、大雷山、龙须山3个居群的果实与种子的形态变异,采用ISSR分子标记技术分析DNA序列的变异,综合评价夏蜡梅3个居群的遗传变异。结果如下:果实性状中,果柄长、果实长、果实重、每果种子数等指标均以大明山居群最大、大雷山居群次之、龙须山居群最小,它们之间差异显著(P<0.05)。种子重、种子长、种子宽、种子厚等指标均以大雷山居群最大,与大明山居群和龙须山居群差异显著(P<0.05)。基于果实形态特征的表型分化系数(VST)在0.5518—0.9750之间,平均为0.8930,所有果实形态指标的变异大部分存在于居群间。基于种子形态特征的VST在0.1669—0.8678之间,平均为0.6240,除种子长外,其他种子形态指标的变异也大部分存在于居群间。ISSR分析表明,3个居群的多态位点百分率、Shannon信息指数、Nei基因多样性均是大明山居群最高、龙须山居群次之、大雷山居群最低。居群间的遗传分化系数(GST)为0.6050。基于ISSR分子标记数据的聚类结果显示大明山居群先与龙须山居群聚在一起,再与大雷山居群相聚,这与基于种子性状特征的聚类结果相似,而与基于果实性状特征的聚类结果不同。3个居群的种子形态特征变异系数与遗传多样性水平具有显著的正相关,且基于果实形态特征估算的VST要高于GST,而基于种子形态特征估算的VST仅略高于GST,表明夏蜡梅不同居群间的种子形态变异主要由遗传变异所造成的,而环境因子在果实形态变异中起了重要作用。Mantel检验显示3个居群基于分子标记数据的遗传距离矩阵和基于果实及种子形态特征的欧氏距离矩阵之间的相关性不显著,表明果实与种子在居群间出现的表型分化除了受遗传因素影响外,还受到其它环境因子的强烈影响。  相似文献   

16.
Small-eared shrews of the New World genus Cryptotis (Eulipotyphla, Soricidae) comprise at least 42 species that traditionally have been partitioned among four or more species groups based on morphological characters. The Cryptotis mexicana species group is of particular interest, because its member species inhibit a subtly graded series of forelimb adaptations that appear to correspond to locomotory behaviors that range from more ambulatory to more fossorial. Unfortunately, the evolutionary relationships both among species in the C. mexicana group and among the species groups remain unclear. To better understand the phylogeny of this group of shrews, we sequenced two mitochondrial and two nuclear genes. To help interpret the pattern and direction of morphological changes, we also generated a matrix of morphological characters focused on the evolutionarily plastic humerus. We found significant discordant between the resulting molecular and morphological trees, suggesting considerable convergence in the evolution of the humerus. Our results indicate that adaptations for increased burrowing ability evolved repeatedly within the genus Cryptotis.  相似文献   

17.
This study provides the first molecular phylogeny of the social wasp subgenus Polistella (Hymenoptera: Vespidae: Polistes) from Vietnam. Fragments of the mitochondrial COI and 16S rRNA genes were used to reconstruct the phylogenetic trees among 38 Polistes species plus two out-group species (Vespa soror du Buysson and Ropalidia fasciata (Fabricius)). Our results support the existence of several species-groups, including two that are congruent with the previous stigma and Stenopolistes groups defined on the basis of morphology. Moreover, we recovered a clade including the stigma group and the two species P. humilis and P. variabilis that was sister to all other species of Polistella. However, the results also challenged the definition of other groups of Polistella based on morphological data, as well as the definition of two species: P. brunus and P. affinis. This first study calls for further analyses including morphological characters to clarify the taxonomy and the classification of the group.  相似文献   

18.
Conflict among data sources can be frequent in evolutionary biology, especially in cases where one character set poses limitations to resolution. Earthworm taxonomy, for example, remains a challenge because of the limited number of morphological characters taxonomically valuable. An explanation to this may be morphological convergence due to adaptation to a homogeneous habitat, resulting in high degrees of homoplasy. This sometimes impedes clear morphological diagnosis of species. Combination of morphology with molecular techniques has recently aided taxonomy in many groups difficult to delimit morphologically. Here we apply an integrative approach by combining morphological and molecular data, including also some ecological features, to describe a new earthworm species in the family Hormogastridae, Hormogaster abbatissae sp. n., collected in Sant Joan de les Abadesses (Girona, Spain). Its anatomical and morphological characters are discussed in relation to the most similar Hormogastridae species, which are not the closest species in a phylogenetic analysis of molecular data. Species delimitation using the GMYC method and genetic divergences with the closest species are also considered. The information supplied by the morphological and molecular sources is contradictory, and thus we discuss issues with species delimitation in other similar situations. Decisions should be based on a profound knowledge of the morphology of the studied group but results from molecular analyses should also be considered.  相似文献   

19.

Background

Rutaceae subfamily Rutoideae (46 genera, c. 660 species) is diverse in both rainforests and sclerophyll vegetation of Australasia. Australia and New Caledonia are centres of endemism with a number of genera and species distributed disjunctly between the two regions. Our aim was to generate a high-level molecular phylogeny for the Australasian Rutoideae and identify major clades as a framework for assessing morphological and biogeographic patterns and taxonomy.

Methodology/Principal Findings

Phylogenetic analyses were based on chloroplast genes, rbcL and atpB, for 108 samples (78 new here), including 38 of 46 Australasian genera. Results were integrated with those from other molecular studies to produce a supertree for Rutaceae worldwide, including 115 of 154 genera. Australasian clades are poorly matched with existing tribal classifications, and genera Philotheca and Boronia are not monophyletic. Major sclerophyll lineages in Australia belong to two separate clades, each with an early divergence between rainforest and sclerophyll taxa. Dehiscent fruits with seeds ejected at maturity (often associated with myrmecochory) are inferred as ancestral; derived states include woody capsules with winged seeds, samaras, fleshy drupes, and retention and display of seeds in dehisced fruits (the last two states adaptations to bird dispersal, with multiple origins among rainforest genera). Patterns of relationship and levels of sequence divergence in some taxa, mostly species, with bird-dispersed (Acronychia, Sarcomelicope, Halfordia and Melicope) or winged (Flindersia) seeds are consistent with recent long-distance dispersal between Australia and New Caledonia. Other deeper Australian/New Caledonian divergences, some involving ant-dispersed taxa (e.g., Neoschmidia), suggest older vicariance.

Conclusions/Significance

This comprehensive molecular phylogeny of the Australasian Rutoideae gives a broad overview of the group’s evolutionary and biogeographic history. Deficiencies of infrafamilial classifications of Rutoideae have long been recognised, and our results provide a basis for taxonomic revision and a necessary framework for more focused studies of genera and species.  相似文献   

20.
The phylogeny of the subfamily Ophioninae (Hymenoptera: Ichneumonidae) is investigated using molecular markers and morphological characters. We analysed the mitochondrial DNA CO1 and the nuclear 28S D2–D3 gene fragments for 74 species of Ophioninae from 25 out of the 32 recognized genera, which collectively represent 98% of described species diversity of the subfamily. Molecular markers were analysed separately and combined, with or without the adjunction of a matrix of 62 morphological characters using Bayesian inference. Our results reveal three distinct lineages, each including one of most speciose genera: Ophion, Enicospilus and Thyreodon. The comparison of the molecular data, and combined molecular plus morphological data led to the definition of the three tribes: Ophionini stat. rev. (Ophion Alophophion Rhopalophion Xylophion Afrophion); Enicospilini stat. rev. (Enicospilus Laticoleus Dicamptus Hellwigiella); and Thyreodonini tribe nov. (Thyreodon Dictyonotus Rhynchophion). The possible association of other genera to one or another of these lineages is discussed. Ophion is a polyphyletic assemblage and requires a further revision to define the delimitation with close genera. The enigmatic Old World genus Skiapus is strongly supported as belonging to the Ophioninae, although its placement within the subfamily is ambiguous as a result of its derived genotype and phenotype. Finally, we propose a biogeographical scenario supported by this phylogeny and based on the limited available fossil data.  相似文献   

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