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The origin of disjunct distributions in high dispersal marine taxa remains an important evolutionary question as it relates to the formation of new species in an environment where barriers to gene flow are not always obvious. To reconstruct the relationships and phylogeographic history of the antitropically and longitudinally disjunct bryozoan Membranipora membranacea populations were surveyed with mtDNA cytochrome oxidase 1 (COI) sequences across its cosmopolitan range. Maximum parsimony, maximum likelihood and Bayesian genealogies revealed three deep clades in the North Pacific and one monophyletic clade each in the southeast Pacific (Chile), southwest Pacific (Australia/New Zealand), North Atlantic and southeast Atlantic (South Africa). Human-mediated dispersal has not impacted M. membranacea’s large-scale genetic structure. M. membranacea did not participate in the trans-arctic interchange. Episodic long-distance dispersal, combined with climatic vicariance can explain the disjunct distribution. Dispersal led southward across the tropics perhaps 13 mya in the East Pacific and again northwards perhaps 6 mya in the Eastern Atlantic to colonize the North Atlantic from the south, and along the West Wind Drift to colonize Australia. The clades differentiated over evolutionary time in their respective ocean region, potentially forming a sibling species complex. The taxonomic status of the clades is discussed.  相似文献   

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One hundred and fourMalassezia strains (52 isolated from humans and 52 from animals) were compared using large subunit (LSU) ribosomal RNA sequence similarity and nuclear DNA complementarity. Eight groups of strains were recognized as genetically distinct species. Each taxon was confirmed by a homogeneous mole % GC and percentages of DNA/DNA reassociations higher than 85%. The non-lipid-dependentMalassezia yeasts were maintained as the unique taxonM. pachydermatis. In contrast, lipid-dependent strains were shown to be distributed among seven species:M. furfur, M. sympodialis andM. species 1–5. These taxa matched remarkably well with morphological and serological differences documented by previous investigators. The LSU rRNA sequences allowed a further intraspecific resolution with most of genomic taxa represented by several closely related sequences:M. pachydermatis counted up to seven sequences,M. furfur four sequences,M. species 1 comprised three sequences andM. species 2 andM. species 5 two sequences. Three species,M. sympodialis, M. species 3 andM. species 4, displayed a unique type of sequence. Thus, the present report demonstrates the usefulness of sequencing for both taxonomic and epidemiological purposes.  相似文献   

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Three new species ofMycogloea are described and illustrated; they are:M. amethystina from Canada,M. nipponica, from Japan, andM. bullata from Thailand.Mycogloea tahitiensis is reported from Japan and additional undescribed taxa in the genus are briefly noted. Some characteristics of the genus are discussed, and a key is provided for six species recognized at this time.  相似文献   

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André M. Amorim 《Brittonia》2003,55(2):127-145
Species of the anomalous-stemmed complex ofHeteropterys are revised after intensive fieldwork in eastern Brazil.Heteropterys patens (=H. anomala) is redefined, and three new species are described (H. admirabilis, H. imperata, andH. nordestina). In addition, this treatment provides brief synonymy, lectotypifications, illustrations, and comments for those four species, and a key to all taxa of the complex.  相似文献   

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Seven isolates ofTorulomyces from Asian and Australian soil samples were studied in comparison with known taxa of the genus and withMonocillium indicum, the type species ofMonocillium. Three new species,Torulomyces parviverrucosus, T. laevis, andT. ovatus, are described, andT. brunneus is described as a new combination. Conidial characteristics, especially their shape and surface structure, are useful taxonomic criteria for distinguishing species ofTorulomyces. Monocillium is considered to be a distinct genus.  相似文献   

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Seventy-three taxa of silica-scaled chrysophytes were found with LM and TEM in 264 samples from 141 Finnish water bodies, including the genera Mallomonas (40 taxa), Synura (9), Chrysosphaerella (3), Spiniferomonas (8) and Paraphysomonas (13). More than half of the taxa are recorded for the first time from Finland and five (Mallomonas actinoloma v. actinoloma, M. favosa, M. mangofera f. gracilis, M. scrobiculata and Spiniferomonas serrata) are new to Europe. Most taxa are illustrated with TEM micrographs and the taxonomy of some interesting species is discussed in detail. The seasonal occurrence of the commonest species is described.  相似文献   

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Medicago intertexta andM. ciliaris have been controversially recognized as separate species. The only reliable diagnostic character, gland-tipped trichomes on the fruits inM. ciliaris, is controlled by presence of a single dominant allele, and such one-character taxonomies are debatable. Contributing to the difficulty,M. muricoleptis andM. granadensis, the other two species ofMedicago sectionSpirocarpos subsectionIntertextae, are sometimes confusingly similar toM. intertexta or to each other. Allozyme differences provided 95% verification of the suitability of the gland-tipped trichome character for separatingM. intertexta andM. ciliaris, thus corroborating their recognition as separate taxa. Several measures of allozyme variation indicated thatM. intertexta is more polymorphic than its sister species. Heterozygosity was also highest inM. intertexta, suggestive of a higher outcrossing rate, which is also consistent with larger floral size. Heterozygosity ofM. intertexta was concentrated in Sicily and nearby countries. Taxonomic difficulties in identifying SicilianM. intertexta are well known, and may be the result of interspecific hybridization and introgression.Medicago muricoleptis differed from the above two species in the frequency of several alleles, whileM. granadensis possessed numerous unique alleles consistent with its complete absence of genetic exchange with the other three substantially interfertile species.  相似文献   

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Three described species of the bryozoan genus Membranipora, M. membranacea (L.), M. serrilamella Osburn, and M. villosa Hincks, occurring together on brown macroalgae off the west coast of North America are eco-phenotypic variants. These forms should be called M. membranacea on the basis of priority.The presence of spines, an important diagnostic feature separating these Membranipora forms, is induced by two nudibranch predators, Corambe pacifica MacFarland & O'Donoghue and Doridella steinbergae Lance. Spines protect Membranipora zooids against predation by these nudibranchs. The population costs of spine production include lower growth and reproductive rates.  相似文献   

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One of the basal Glyptodontidae groups is represented by the Propalaehoplophorinae (late Oligocene — middle Miocene), whose genera (Propalaehoplophorus, Eucinepeltus, Metopotoxus, Cochlops, andAsterostemma) were initially recognized in Argentinian Patagonia. Among these,Asterostemma was characterized by its wide latitudinal distribution, ranging from southernmost (Patagonia) to northernmost (Colombia, Venezuela) South America. However, the generic assignation of the Miocene species from Colombia and Venezuela (A.? acostae, A. gigantea, andA. venezolensis) was contested by some authors, who explicitly accepted the possibility that these species could correspond to a new genus, different from those recognized in southern areas. A new comparative study of taxa from Argentinian Patagonia, Colombia and Venezuela (together with the recognition of a new genus and species for the Pliocene of the latter country) indicates that the species in northern South America are not Propalaehoplophorinae, but represent the first stages in the cladogenesis of the Glyptodontinae glyptodontids, the history of which was heretofore restricted to the late Miocene — early Holocene of southernmost South America. Accordingly, we propose the recognition of the new genusBoreostemma for the species from northern South America and the restriction ofAsterostemma to the Miocene of Patagonia. Thus, the available data indicate that the Glyptodontinae would in fact have arisen in the northernmost regions of this continent. Their arrival to more southerly areas coincides with the acme of the “Age of Southern Plains”. The Propalaehoplophorinae are geographically restricted to Patagonia.  相似文献   

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A new taxonomic treatment is proposed for thePottia starckeana species complex. The peristome development is not considered to be a useful feature to separate the taxa. On the basis of spore morphology only two species are accepted:P. starckeana, with spores wavy in outline, andP. davalliana, with variously-shaped and developed processes on the spores.Pottia starckeana var.brachyoda is reduced to synonymy withP. starckeana; P. conica andP. commutata are treated as synonyms ofP. davalliana. The speciesP. mutica, P. affinis, P. salina, P. microphylla, P. texana, andP. arizonica (included var.mucronulata) are considered taxa of doubtful affinity, as they have spore features intermediate between the two spore types established for the group. The identity ofP. appertii andP. recurvifolia has not been elucidated because the type material has been destroyed.  相似文献   

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Nutritional physiological and tolerance tests were performed for all type strains of species currently classified in the black yeast generaExophiala andPhaeococcomyces, including some additional type strains of taxa recently reidentified asExophiala species. Most describedExophiala species can be distinguished by physiological characters.Exophiala jeanselmei with its varieties, andE. castellanii should all be retained as separate taxa. The pairs of strainsMycotorula schawii/Exophiala dermatitidis, Hormodendrum negronii/Exophiala jeanselmei var.lecaniicorni andSporotrichum gougerotii/Torula bergeri were found to be conspecific. Phenetic analyses of physiological data support the identity ofPhaeococcomyces exophialae as a yeast-like synanamorph ofExophiala spinifera. The taxonomic positions of the generaNadsoniella, Phaeoannellomyces andWangiella are discussed. The generaExophiala andPhaeococcomyces are unrelated.  相似文献   

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André M. Amorim 《Brittonia》2002,54(4):217-232
Five-new taxa ofHeteropterys H. B. K. subsect.Aptychia Nied. are described, illustrated, and mapped:H. andina from Peru;H. minutiflora from Costa Rica; andH. bullata, H. capixaba, andH. oberdanii, from the Atlantic coastal forest of Brazil. The affinities and diagnostic characters of each species are discussed.  相似文献   

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本文报告了团毛菌科中的二个新种:Perichaena membranea sp. nov.; Perichaena poronema sp. nov及二个国内新纪录种:Trichia erecta Rex和Arcyria abietina (A.Wigand) N. E. Nannenga-Bremekamp.新种有拉T文描述及扫描电镜照片,讨论了新种与相近种的关系。模式标本收藏于HMAS北京和HJAU长春。  相似文献   

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