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 109 毫秒
1.
We sequenced the nuclear small subunit of ribosomal DNA (SSU rDNA) from seven species within the insect-pathogenic order Entomophthorales. These sequences were aligned with other published SSU rDNA sequences and phylogenies were inferred using phenetic and cladistic methods. Based on three different phylogenetic methods the Entomophthorales (excludingBasidiobolus ranarum) is monophyletic;B. ranarumwas more closely related to chytrids from Chytridiales and Neocallimasticales than to Entomophthorales, as was proposed by Nagahamaet al.(Mycologia87:203–209, 1995). Nuclear characters (large nuclei containing conspicuous condensed chromatin and lack of a prominent nucleolus) were of predictive value for the monophyly of the family Entomophthoraceae. Conidial characters separate the Entomophthoraceae, which only includes obligate pathogens, into at least two lineages: one lineage with uninucleate conidia and another with multinucleate conidia. The two species ofConidiobolusstudied were paraphyletic in our analyses and only distantly related to each other. This information may prove to be important in the use of these fungi as biocontrol agents.  相似文献   

2.
A phylogenetic study of marine ascomycetes was initiated to test and refine evolutionary hypotheses of marine-terrestrial transitions among ascomycetes. Taxon sampling focused on the Halosphaeriales, the largest order of marine ascomycetes. Approximately 1050 base pairs (bp) of the gene that codes for the nuclear small subunit (SSU) and 600 bp of the gene that codes for the nuclear large subunit (LSU) ribosomal RNAs (rDNA) were sequenced for 15 halosphaerialean taxa and integrated into a data set of homologous sequences from terrestrial ascomycetes. An initial set of phylogenetic analyses of the SSU rDNA from 38 taxa representing 15 major orders of the phylum Ascomycota confirmed a close phylogenetic relationship of the halosphaerialean species with several other orders of perithecial ascomycetes. A second set of analyses, which involved more intensive taxon sampling of perithecial ascomycetes, was performed using the SSU and LSU rDNA data in combined analyses. These second analyses included 15 halosphaerialean taxa, 26 terrestrial perithecial fungi from eight orders, and five outgroup taxa from the Pezizales. In these analyses the Halosphaeriales were polyphyletic and comprised two distinct lineages. One clade of Halosphaeriales comprised 12 taxa from 11 genera and was most closely related to terrestrial fungi of the Microascales. The second clade of halosphaerialean fungi comprised taxa from the genera Lulworthia and Lindra and was an isolated lineage among the perithecial fungi. Both the main clade of Halosphaeriales and the Lulworthia/Lindra clade are supported by the data as being independently derived from terrestrial ancestors.  相似文献   

3.
4.
Phylogenies inferred from the analysis of DNA sequence data have shown that the Onygenales contains clades that do not correspond with previously described families. One lineage identified in recent molecular phylogenetic studies includes the dimorphic pathogens belonging to the genera Ajellomyces, Emmonsia and Paracoccidioides. To evaluate the degree of support for this lineage and determine whether it includes additional taxa, we examined relationships among the members of this clade and selected saprobic onygenalean taxa based on maximum-parsimony analyses of partial nuclear large RNA subunit (LSU) and internal transcribed spacer (ITS) sequences. A clade distinct from the Onygenaceae was found to encompass Ajellomyces (including the anamorph genera Blastomyces, Emmonsia and Histoplasma) and Paracoccidioides brasiliensis. The members of this lineage are saprobic and pathogenic vertebrate-associated taxa distinguished by their globose ascomata with coiled appendages, muricate globose or oblate ascospores, and lack of keratinolytic activity. Anamorphs are solitary aleurioconidia or irregular alternate arthroconidia. Based on molecular data and on morphological and physiological similarities among these taxa, we propose the new family, Ajellomycetaceae.  相似文献   

5.
Summary. The natural occurrence of fungal pathogens of aphids and their ecological host range was investigated in Tunisia from 2009 to 2012. The survey focused on aphid infesting different crops and weeds and included 10 different aphid species. Samples were collected from eight agricultural crops sites belonging to three different bioclimatic zones. Four pathogens from the phylum Entomophthoromycota were found to occur naturally in Tunisian ecosystems: Pandora neoaphidis (Entomophthorales: Entomophthoraceae), Entomophthora planchoniana (Entomophthorales: Entomophthoraceae), Conidiobolus obscurus (Entomophthorales: Ancylistaceae) and Neozygites fresenii (Neozygitales: Neozygitaceae). The occurrence of entomophthoralean fungi depended on the sampling area, the bioclimatic zone, and aphid species. P. neoaphidis and E. planchoniana were the predominant pathogens infecting a wide range of aphid species whereas C. obscurus and N. fresenii were sporadically present on a limited number of aphid species. This study is the first survey on ecological host range of entomophthoralean fungi in Tunisia, and the first documentation of C. obscurus and N. fresenii to occur in Tunisia and Maghreb Region.  相似文献   

6.
A phylogenetic analysis of DNA sequences from the internal transcribed spacer (ITS), the external transcribed spacer (ETS), and the 5.8S regions of 18S-26S nuclear rDNA from all diploid species of Stephanomeria and related genera shows that Stephanomeria does not include either Munzothamnus blairii (previously S. blairii) or Pleiacanthus spinosus (previously S. spinosa). Without these two taxa, Stephanomeria is a well-supported (100% bootstrap), monophyletic group of ten perennial and six annual species. Munzothamnus blairii and Pleiacanthus spinosus, both now considered members of monotypic genera, had been placed in Stephanomeria primarily because they have the same chromosome number as Stephanomeria and similar pollen surface features, but many disparities were ignored in previous classifications. Within Stephanomeria, an unsuspected sister relationship was detected between the montane S. lactucina and coastal S. cichoriacea. A second clade contained all the annual taxa and five of the perennial species. Among the annuals, strong bootstrap support was obtained for the previously recognized relationships between S. diegensis and S. exigua (98%) and between S. malheurensis and its progenitor, S. exigua subsp. coronaria (96%). Among the five perennial species that constitute a clade with the annuals, the recently described S. fluminea was shown to be sister to S. runcinata, and both of them were closely allied to S. tenuifolia and S. thurberi. The clade including the annuals (and five of the perennial species) was subtended by perennial lineages and pairwise divergence values among the annual taxa were much lower than among the perennial taxa as a group (though not too different than among the perennials in the same clade). The annuals probably originated recently within the genus.  相似文献   

7.
We generated the first complete phylogeny of extant taxa in a well-defined clade of 26 starling species that is collectively distributed across Eurasia, and which has one species endemic to sub-Saharan Africa. Two species in this group-the European starling Sturnus vulgaris and the common Myna Acridotheres tristis-now occur on continents and islands around the world following human-mediated introductions, and the entire clade is generally notable for being highly social and dispersive, as most of its species breed colonially or move in large flocks as they track ephemeral insect or plant resources, and for associating with humans in urban or agricultural landscapes. Our reconstructions were based on substantial mtDNA (4 kb) and nuclear intron (4 loci, 3 kb total) sequences from 16 species, augmented by mtDNA NDII gene sequences (1 kb) for the remaining 10 taxa for which DNAs were available only from museum skin samples. The resulting mitochondrial gene tree embedded within a multilocus framework shows that the well-studied taxa S. vulgaris/unicolor are the sister lineage to the remaining members of the radiation, from which other relatively early lineages gave rise to forms that are now nomadic or locally migrant in Africa (Creatophora) and western Asia (Pastor). The remaining taxa form a clade with a complicated biogeographic history primarily in central and eastern Asia; this group contains a range of sedentary to highly migratory taxa, as well as widely distributed species and single-island endemics such as the highly endangered Bali myna (Leucopsar). Several groups of species in the genus Acridotheres have low magnitudes of within-group divergence and likely diversified via their respective colonization of islands. The taxonomy of this entire group has remained highly volatile over the past century; we propose dividing these 26 species among 11 reciprocally monophyletic genera (Acridotheres, Poliopsar, Temenuchus, Sturnornis, Leucopsar, Gracupica, Agropsar, Pastor, Creatophora, and Sturnus).  相似文献   

8.
We investigated the phylogenetic relationships among monogenean parasites of the Chaetodontidae (butterflyfishes) from the Indo-West Pacific Ocean. Molecular phylogenies of selected taxa within the Dactylogyridae, including the ancyrocephaline parasites of butterflyfishes, based on two nuclear and one mitochondrial gene fragments (complete 18S rDNA, partial 28S rDNA (D1-D3), and partial 16S rDNA) were reconstructed using parsimony, maximum likelihood and Bayesian inference methods. Our results show the non-monophyletic nature of the monogenean fauna of butterflyfishes. The group is divided into two independent lineages. The first clade contains species of the genera Aliatrema and Euryhaliotrematoides , which parasitize Chaetodontidae exclusively. The second contains species of Haliotrema , a generalist group of parasites. The positions of several other species of the Ancyrocephalinae, including freshwater species, at the base of the two clades, provide strong evidence that the monogenean fauna did not result from a single colonization event, but rather that they have colonized their butterflyfish hosts independently at least twice.  相似文献   

9.
Aime MC  Phillips-Mora W 《Mycologia》2005,97(5):1012-1022
The two most devastating diseases of cacao (Theobroma cacao)--the source of chocolate--in tropical America are caused by the fungi Crinipellis perniciosa (witches' broom disease) and Moniliophthora roreri (frosty pod rot or moniliasis disease). Despite the agricultural, socio-economic and environmental impact of these fungi, most aspects of their life cycles are unknown, and the phylogenetic relationships of M. roreri have yet to be conclusively established. In this paper, extensive phylogenetic analyses of five nuclear gene regions (28S rDNA, 18S rDNA, ITS, RPB1, and EF1-alpha) confirm that C. perniciosa and M. roreri are sister taxa that belong in the Marasmiaceae (euagarics). Furthermore, these taxa form part of a separate and distinct lineage within the family. This lineage includes the biotrophic fungi Moniliophthora perniciosa comb. nov. and M. roreri, as well as one undescribed endophytic species. The sister genera to Moniliophthora are Marasmius, Crinipellis and Chaetocalathus, which consist mainly of saprotrophic litter fungi.  相似文献   

10.
从18S rDNA序列初探散胞盘菌亚科属间亲缘关系   总被引:1,自引:1,他引:0  
散胞盘菌亚科Encoelioideae建于1932年,为盘菌纲Discomycetes锤舌菌目Leotiales锤舌菌科(广义)Leotiaceae的成员,它包括腐生、植物寄生、真菌上生的盘状子囊菌,现含18属,其中若干为单种属。传统分类从形态学角度将外囊盘表层细胞松散结合或者表面覆盖短的菌丝延伸物视为此亚科的主要特征,宏观上,其成员的共性表现为外囊盘被表面糠皮状、鳞屑状或霜状。迄今,学者们从未对散孢盘菌亚科这一性状是否反映属间亲缘关系进行过任何探讨,国际基因库中亦无此亚科的可利用序列。为了探明此性状在系统演化过程中的作用以及散胞盘菌亚科的属间亲缘关系,我们对此亚科中绿散胞盘菌Chlorencoelia、复柄盘菌属Cordierites、散胞盘菌属Encoelia、霍氏盘菌属Holwaya、拟爪毛盘菌属 Unguiculariopsis、以及丝绒盘菌属Velutarina代表种的18SrDNA片段进行了序列测定,受实验材料所限,每属只获得了一个种的18SrDNA序列。为了分析和比较,还对同一科内锤舌菌亚科Leotioideae中绿杯菌属Chlorociboria一个种的相关序列进行了测定。在构建系统树的过程中,核盘菌科的核盘菌Sclerotiniasclerotiorum被选为外群;从基因库中调入属于同一个目的地舌菌科和锤舌菌亚科几个属的代表即胶鼓菌属Bulgaria、锤舌菌属Leotia、小舌菌属Microglossum、新胶鼓菌属Neobulgaria和地勺菌属Spathularia的序列;利用ClustalW和TreeView软件,构建出Neighbour-joining系统进化树。初步的研究结果表明,散孢盘菌亚科不是单源的,该亚科的成员与其他亚科或者其他科的物种一起形成四个系统演化分支。散胞盘菌亚科的Holwaya与另一亚科的Bulgaria(Leotiaceae,Leotioideae)聚在一起,具有95%的序列相似性和97.4%支持率(bootstrapvalue);此二属与Leotia(Leotiaceae,Leotioideae)和Microglossum(Geoglossaceae)组成姐妹群。散胞盘菌亚科Cordierites和Encoelia接近,支持率为93.6%;它们是Leotioideae中Chlorociboria和Neobulgaria两属的姐妹群。散胞盘菌亚科的Unguiculariopsis与Velutarina在一起,独立成为一个分支,支持率高达99.3%。Chlorencoelia与本研究所涉及的散胞盘菌亚科其他成员的关系都比较远。以上研究结果表明,散胞盘菌亚科很可能是多源的;但是,由于该亚科大多数属缺乏分子生物学证据,本研究结果只能作为推断。  相似文献   

11.
从18SrDNA序列初探散胞盘菌亚科属间亲缘关系   总被引:1,自引:0,他引:1  
散胞盘菌亚科Encoelioideae建于1932年,为盘菌纲Discomycetes锤舌菌目Leotiales锤舌菌科(广义)Leotiaceae的成员,它包括腐生、植物寄生、真菌上生的盘状子囊菌,现含18属,其中若干为单种属。传统分类从形态学角度将外囊盘表层细胞松散结合或者表面覆盖短的菌丝延伸物视为此亚科的主要特征,宏观上,其成员的共性表现为外囊盘被表面糠皮状、鳞屑状或霜状。迄今,学者们从未对散孢盘菌亚科这一性状是否反映属间亲缘关系进行过任何探讨,国际基因库中亦无此亚科的可利用序列。为了探明此性状在系统演化过程中的作用以及散胞盘菌亚科的属间亲缘关系,我们对此亚科中绿散胞盘菌Chlorencoelia、复柄盘菌属Cordierites、散胞盘菌属Encoelia、霍氏盘菌属Holwaya、拟爪毛盘菌属Unguiculariopsis、 以及丝绒盘菌属Velutarina代表种的18S rDNA片段进行了序列测定,受实验材料所限,每属只获得了一个种的18S rDNA序列。为了分析和比较,还对同一科内锤舌菌亚科Leotioideae中绿杯菌属Chlorociboria一个种的相关序列进行了测定。在构建系统树的过程中,核盘菌科的核盘菌Sclerotinia sclerotiorum被选为外群;从基因库中调入属于同一个目的地舌菌科和锤舌菌亚科几个属的代表即胶鼓菌属Bulgaria、锤舌菌属Leotia、?  相似文献   

12.
Recent phylogenetic studies of tetrasporalean exemplars using 18S rDNA revealed the extent of diversity among taxa in this non-monophyletic group (Booton et al. 1998). In particular, two distinct tetrasporalean lineages were identified; one group allied with chlamydomonadalean taxa and the other group comprising taxa now placed in a separate order, the Chaetopeltidales. Using these observations as a framework, a new investigation of diversity among a broader sampling of putative tetrasporalean genera (e.g. Asterococcus , Chloranomala , Chlorophysema , Gloeocystis , Gloeodendron , Palmella , Paulschulzia , Physocytium , Schizochlamys and Tetraspora ) was undertaken. Phylogenetic studies of both 18S and 26S rDNA were compared with ultrastructural investigations of vegetative cells. Molecular phylogenetic analyses corroborate the earlier 18S rDNA results, but also reveal additional diversity. The new data raise doubts regarding the monophyly of two genera, Palmella and Tetraspora. The new data also link two enigmatic green algal genera, Physocytium and Heterochlamydomonas , in a long-branch lineage within the Chlamydomonadales. Another enigmatic genus, Schizochlamys , is allied with Bracteacoccus in the Sphaeropleales. Lastly, Chloranomala is resolved as an ally of Paulschulzia , Tetraspora sp., and the green flagellate, Lobomonas. Comparison of pyrenoid ultrastructure generally supports the molecular phylogenetic analyses, suggesting that this non-molecular character will be a useful marker for broad phylogenetic studies of chlamydomonadalean taxa. (Supported by NSF grant, DEB 9726588)  相似文献   

13.
Ants are one of the most ecologically and numerically dominant families of organisms in almost every terrestrial habitat throughout the world, though they include only about 1% of all described insect species. The development of eusociality is thought to have been a driving force in the striking diversification and dominance of this group, yet we know little about the evolution of the major lineages of ants and have been unable to clearly determine their primitive characteristics. Ants within the subfamily Amblyoponinae are specialized arthropod predators, possess many anatomically and behaviorally primitive characters and have been proposed as a possible basal lineage within the ants. We investigate the phylogenetic relationships among the members of the subfamily, using nuclear 28S rDNA sequence data. Outgroups for the analysis include members of the poneromorph and leptanillomorph (Apomyrma, Leptanilla) ant subfamilies, as well as three wasp families. Parsimony, maximum likelihood, and Bayesian analyses provide strong support for the monophyly of a clade containing the two genera Apomyrma+Mystrium (100% bpp; 97% ML bs; and 97% MP bs), and moderate support for the monophyly of the Amblyoponinae as long as Apomyrma (Apomyrminae) is included (87% bpp; 57% ML bs; and 76% MP bs). Analyses did not recover evidence of monophyly of the Amblyopone genus, while the monophyly of the other genera in the subfamily is supported. Based on these results we provide a morphological diagnosis of the Amblyoponinae that includes Apomyrma. Among the outgroup taxa, Typhlomyrmex grouped consistently with Ectatomma, supporting the recent placement of Typhlomyrmex in the Ectatomminae. The results of this present study place the included ant subfamilies into roughly two clades with the basal placement of Leptanilla unclear. One clade contains all the Amblyoponinae (including Apomyrma), Ponerinae, and Proceratiinae (Poneroid clade). The other clade contains members from subfamilies Cerapachyinae, Dolichoderinae, Ectatomminae, Formicinae, Myrmeciinae, and Myrmicinae (Formicoid clade).  相似文献   

14.
The phylogenetic lineage, taxonomic affiliation and interrelationships of important asexual entomopathogenic fungal genera were studied using the sequences of partial regions of β-tubulin and rRNA genes. The species structures of Beauveria bassiana and Nomuraea rileyi were also investigated. A total of 147 fungal entries covering 94 species were analysed. Phylogenetic analysis placed all the asexual entomopathogenic fungal species analysed, in the family Clavicipitaceae of the order Hypocreales of Ascomycota. Deep phylogenetic lineages were observed in B. bassiana iterating the complex nature of this species. Some of the isolates assigned to this species separated out more distinctly than morphologically distinguishable genera. Cryptic speciation was also evident in N. rileyi. It is concluded that the asexual fungi with entomopathogenic habit arose from a single lineage in sexual Clavicipitaceae.  相似文献   

15.
Numerous species of microscopic fungi inhabit mosses and hepatics. They are severely overlooked and their identity and nutritional strategies are mostly unknown. Most of these bryosymbiotic fungi belong to the Ascomycota. Their fruit‐bodies are extremely small, often reduced and simply structured, which is why they cannot be reliably identified and classified by their morphological and anatomical characters. A phylogenetic hypothesis of bryosymbiotic ascomycetes is presented. New sequences of 78 samples, including 61 bryosymbionts, were produced, the total amount of terminals being 206. Of these, 202 are Ascomycetes. Sequences from the following five gene loci were used: rDNA SSU, rDNA LSU, RPB2, mitochondrial rDNA SSU, and rDNA 5.8S. The program TNT was used for tree search and support value estimation. We show that bryosymbiotic fungi occur in numerous lineages, one of which represents a newly discovered lineage among the Ascomycota and exhibits a tripartite association with cyanobacteria and sphagna. A new genus Trizodia is proposed for this basal clade. Our results demonstrate that even highly specialized life strategies can be adopted multiple times during evolution, and that in many cases bryosymbionts appear to have evolved from saprobic ancestors. © The Willi Hennig Society 2009.  相似文献   

16.
Ronikier M  Ronikier A 《Mycologia》2011,103(5):1124-1132
As a part of a large-scale biogeographical study we examined the evolutionary relationships and taxonomic position of Marasmius epidryas, one of the most typical circumpolar arctic-alpine fungi, characterized by a specific, saprobic affinity to dead tissues of Dryas spp. A phylogenetic analysis based on nLSU and RPB2 DNA regions unequivocally indicated the phylogenetic placement of this species within the Physalacriaceae. The Bayesian MCMCMC analysis as well as other inference methods tested (ML, NJ) revealed a well supported affinity of M. epidryas to Rhizomarasmius pyrrhocephalus, type species of a recently circumscribed genus, Rhizomarasmius. As a consequence, based on these results, we introduce a new combination, Rhizomarasmius epidryas (Kühner ex A. Ronikier) A. Ronikier and M. Ronikier. Thus our results demonstrate that neither the traditional taxonomic placement of the fungus in genus Marasmius nor the recent transfer into genus Mycetinis are phylogenetically correct. In contrast they support the importance of the third lineage of the polyphyletic Marasmius s. l., having evolutionary links with taxa forming the Physalacriaceae clade of agaricoid fungi. In addition the lineage of Rhizomarasmius was confirmed to be closely related to the representatives of Gloiocephala, comprising small, often narrowly specialized saprobic species previously also classified within Marasmius s. l.  相似文献   

17.
Group I introns were discovered inserted at the same position in the nuclear small-subunit ribosomal DNA (nuc-ssu-rDNA) in several species of homobasidiomycetes (mushroom-forming fungi). Based on conserved intron sequences, a pair of intron-specific primers was designed for PCR amplification and sequencing of intron-containing rDNA repeats. Using the intron-specific primers together with flanking rDNA primers, a PCR assay was conducted to determine presence or absence of introns in 39 species of homobasidiomycetes. Introns were confined to the genera Panellus, Clavicorona, and Lentinellus. Phylogenetic analyses of nuc-ssu-rDNA and mitochondrial ssu-rDNA sequences suggest that Clavicorona and Lentinellus are closely related, but that Panellus is not closely related to these. The simplest explanation for the distribution of the introns is that they have been twice independently gained via horizontal transmission, once on the lineage leading to Panellus, and once on the lineage leading to Lentinellus and Clavicorona. BLAST searches using the introns from Panellus and Lentinellus as query sequences retrieved 16 other similar group I introns of nuc-ssu-rDNA and nuclear large-subunit rDNA (nuc-lsu-rDNA) from fungal and green algal hosts. Phylogenetic analyses of intron sequences suggest that the mushroom introns are monophyletic, and are nested within a clade that contains four other introns that insert at the same position as the mushroom introns, two from different groups of fungi and two from green algae. The distribution of host lineages and insertion sites among the introns suggests that horizontal and vertical transmission, homing, and transposition have been factors in intron evolution. As distinctive, heritable features of nuclear rDNAs in certain lineages, group I introns have promise as phylogenetic markers. Nevertheless, the possibility of horizontal transmission and homing also suggest that their use poses certain pitfalls.   相似文献   

18.
We examined phylogeographic relationships in the cosmopolitan polypore fungus Ganoderma applanatum and allies, and conservatively infer a possible age of origin for these fungi. Results indicate that it is very unlikely that members of this species complex diversified before the break-up of Gondwana from Laurasia ca 120 M years ago, and also before the final separation of the Gondwanan landmasses from each other that was achieved about 66 M years ago. An earliest possible age of origin of 30 M years was estimated from nucleotide substitution rates in the 18S rDNA gene. Phylogenetic reconstruction of a worldwide sampling of ITS rDNA sequences reveals at least eight distinct clades that are strongly correlated with the geographic origin of the strains, and also correspond to mating groups. These include one Southern Hemisphere clade, one Southern Hemisphere–Eastern Asia clade, two temperate Northern Hemisphere clades, three Asian clades, and one neotropical clade. Geographically distant collections from the Southern Hemisphere shared identical ITS haplotypes, and an ITS recombinant was noted. Nested clade analysis of a parsimony network among isolates of the Southern Hemisphere clade indicated restricted gene flow with isolation-by-distance among the New Zealand, Australia–Tasmania, Chile–Argentine, and South Africa populations, suggesting episodic events of long-distance dispersal within the Southern Hemisphere. This study indicates that dispersal bias plays a more important role than generally admitted to explain the Southern Hemisphere distribution of many taxa, at least for saprobic fungi.  相似文献   

19.
Phylogenetic analyses of Polytrichales were conducted using morphology and sequence data from the chloroplast genes rbcL and rps4 plus the trnL-F gene region, part of the mitochondrial nad5 and the nuclear-encoded 18S rDNA. Our analyses included 46 species representing all genera of Polytrichales. Phylogenetic trees were constructed with simultaneous parsimony analyses of all sequences plus morphology and separate combinations of sequence data only. Results lend support for recognition of Polytrichales as a monophyletic entity. Oedipodium griffithianum appears as a sister taxon to Polytrichales or as a sister taxon of all mosses excluding Sphagnales and Andreaeles. Within Polytrichales, Alophosia and Atrichopsis, species without the adaxial lamellae (in Atrichopsis present but poorly developed on male gametophyte) otherwise typical of the group are sister to the remaining species followed by a clade including Bartramiopsis and Lyellia, species with adaxial lamellae covering only the central portion of the leaves. Six taxa with an exclusively Southern Hemisphere distribution form a grade between the basal lineages and a clade including genera that are mostly confined to the Northern Hemisphere.  相似文献   

20.
The hybrid stick insect genus Acanthoxyla Uvarov 1944 is unusual for an obligate parthenogen, in the extreme morphological diversity it exhibits that has led to eight species being recognised. The New Zealand sexual species Clitarchus hookeri [White, A. 1846. The zoology of the Voyage of H.M.S. Erebus and Terror. In: 1 Insects of New Zealand. E.W. Janson, London.] is the putative parental species in the hybridization that gave rise to the hybrid lineage Acanthoxyla. In an effort to identify the maternal ancestor of Acanthoxyla we sequenced nuclear 28S rDNA and/or mtDNA COI & COII of all nine endemic New Zealand stick insect genera, representing 17 of the 22 described species. We also sequenced 28S from eight non-New Zealand stick insects to supplement published 28S sequence data that provided a taxonomically and geographically broad sampling of the phasmids. We applied a novel search algorithm (SeqSSi=Sequence Similarity Sieve) to assist in selection of outgroup taxa for phylogenetic analysis prior to alignment. Phylogenetic reconstructions resolved an exclusively New Zealand clade to which the maternal lineage of Acanthoxyla belonged, but did not support existing higher level taxonomy of stick insects. We did not find a sexual maternal species for Acanthoxyla but phylogenetic relationships indicate that this species lived in New Zealand and could be classified among the New Zealand Phasmatinae. Among the available taxa, the nearest evolutionary neighbours to the New Zealand phasmid fauna as a whole were predominantly from the New Zealand region (Fiji, Australia, New Guinea, New Caledonia and South America). As it appears to be an orphan, it is interesting to speculate that a combination of parthenogenetic reproduction and/or hybrid vigour in Acanthoxyla may have contributed to the extinction of its mother.  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