79 resultados para Taxonomic impediment


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This study clarifies the taxonomic status of Anemone coronaria and segregates the species and A. coronaria infraspecific variants using morphological and morphometric analyses. Principal component analysis of the coronaria group was performed on 25 quantitative and qualitative characters, and morphometric analysis of the A. coronaria infraspecific variants was performed on 21 quantitative and qualitative characters. The results showed that the A. coronaria group clustered into four major groups: A. coronaria L., A. biflora DC, A. bucharica (Regel) Juz.ex Komarov, and a final group including A. eranthioides Regel and A. tschernjaewii Regel. The data on the A. coronaria infraspecific variants clustered into six groups: A. coronaria L. var. coronaria L., var. cyanea Ard., var. albiflora Rouy & Fouc., var. parviflora Regel, var. ventreana Ard., and var. rissoana Ard. © 2007 The Linnean Society of London

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The Species 2000 & ITIS Catalogue of Life is planned to become a comprehensive catalogue of all known species of organisms on Earth by the year 2011. Rapid progress has been made recently and this, the sixth edition of the Annual Checklist, contains 884,552 species, approximately half of all known organisms. The present Catalogue is compiled with sectors provided by 37 taxonomic databases from around the world. Many of these contain taxonomic data and opinions from extensive networks of specialists, so that the complete work contains contributions from an estimated 2-3,000 specialists from throughout the taxonomic profession. The work of the Species 2000 and ITIS teams is to peer review databases, select appropriate sectors and to integrate the sectors into a single coherent catalogue with a single hierarchical classification. It is planned in future to introduce alternative taxonomic treatments and alternative hierarchies, but an important feature is that for those users who wish to use it, a single preferred catalogue, based on peer reviews, will continue to be provided.

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The clouded leopard, Neofelis nebulosa, is an endangered semiarboreal felid with a wide distribution in tropical forests of southern and southeast Asia, including the islands of Sumatra and Borneo in the Indonesian archipelago [1]. In common with many larger animal species, it displays morphological variation within its wide geographical range and is currently regarded as comprising of up to four subspecies [2-4]. It is widely recognized that taxonomic designation has a major impact on conservation planning and action [5-8]. Given that the last taxonomic revision was made over 50 years ago [2], a more detailed examination of geographical variation is needed. We describe here the results of a morphometric analysis of the pelages of 57 clouded leopards sampled throughout the species' range. We conclude that there are two distinct morphological groups, which differ primarily in the size of their cloud markings. These results are supported by a recent genetic analysis [9]. On that basis, we give diagnoses for the distinction of two species, one in mainland Asia (N. nebulosa) and the other in Indonesia (N. diardi). The implications for conservation that arise from this new taxonomic arrangement are discussed.

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Exaggerated male traits that have evolved under sexual selection include ornaments to attract mates and weapons to deter rivals. Data from studies of many such traits in diverse kinds of organisms show that they almost universally exhibit positive allometries. Both ornaments and weapons increase disproportionately with overall body size, resulting in scaling exponents within species that are consistently > 1.0 and usually in the range 1.5-2.5. We show how scaling exponents reflect the relative fitness advantages of ornaments vs. somatic growth by using a simple mathematical model of resource allocation during ontogeny. Because the scaling exponents are similar for the different taxonomic groups, it follows that the fitness advantages of investing in ornaments also are similar. The model also shows how selection for ornaments influences body size at first reproduction and explains why interspecific allometries have consistently lower exponents than intraspecific ones.

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Crop wild relatives are an important socio-economic resource that is currently being eroded or even extinguished through careless human activities. If the Conference of the Parties (COP) to the CBD 2010 Biodiversity Target of achieving a significant reduction in the current rate of loss is to be achieved, we must first define what crop wild relatives are and how their conservation might be prioritised. A definition of a crop wild relative is proposed and illustrated in the light of previous Gene Pool concept theory. Where crossing and genetic diversity information is unavailable, the Taxon Group concept is introduced to assist recognition of the degree of crop wild relative relatedness by using the existing taxonomic hierarchy.

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Myosotic cameroonensis Cheek & R Becker (Boraginacene) is described from Cameroon. Its conservation status and taxonomic affinities are assessed and an updated key to the Tropical African species of the genus is presented.

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Attitudes to floristics have changed considerably during the past few decades as a result of increasing and often more focused consumer demands, heightened awareness of the threats to biodiversity, information flow and overload, and the application of electronic and web-based techniques to information handling and processing. This paper will examine these concerns in relation to our floristic knowledge and needs in the region of SW Asia. Particular reference will be made to the experience gained from the Euro+Med PlantBase project for the preparation of an electronic plant-information system for Europe and the Mediterranean, with a single core list of accepted plant names and synonyms, based on consensus taxonomy agreed by a specialist network. The many challenges Ð scientific, technical and organisational Ð that it has presented will be discussed as well as the problems of handling nontaxonomic information from fields such as conservation, karyology, biosystematics and mapping. The question of regional cooperation and the sharing of efforts and resources will also be raised and attention drawn to the recent planning workshop held in Rabat (May 2002) for establishing a technical cooperation network for taxonomic capacity building in North Africa as a possible model for the SW Asia region.

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Resolving the relationships between Metazoa and other eukaryotic groups as well as between metazoan phyla is central to the understanding of the origin and evolution of animals. The current view is based on limited data sets, either a single gene with many species (e.g., ribosomal RNA) or many genes but with only a few species. Because a reliable phylogenetic inference simultaneously requires numerous genes and numerous species, we assembled a very large data set containing 129 orthologous proteins (similar to30,000 aligned amino acid positions) for 36 eukaryotic species. Included in the alignments are data from the choanoflagellate Monosiga ovata, obtained through the sequencing of about 1,000 cDNAs. We provide conclusive support for choanoflagellates as the closest relative of animals and for fungi as the second closest. The monophyly of Plantae and chromalveolates was recovered but without strong statistical support. Within animals, in contrast to the monophyly of Coelomata observed in several recent large-scale analyses, we recovered a paraphyletic Coelamata, with nematodes and platyhelminths nested within. To include a diverse sample of organisms, data from EST projects were used for several species, resulting in a large amount of missing data in our alignment (about 25%). By using different approaches, we verify that the inferred phylogeny is not sensitive to these missing data. Therefore, this large data set provides a reliable phylogenetic framework for studying eukaryotic and animal evolution and will be easily extendable when large amounts of sequence information become available from a broader taxonomic range.

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The Bryaceae are a large cosmopolitan family of mosses containing genera of considerable taxonomic difficulty. Phylogenetic relationships within the family were inferred using data from chloroplast DNA sequences (rps4 and trnL-trnF region). Parsimony and maximum likelihood optimality criteria, and Bayesian phylogenetic inference procedures were employed to reconstruct relationships. The genera Bryum and Brachymenium are not monophyletic groups. A clade comprising Plagiobryum, Acidodontium, Mielichhoferia macrocarpa, Bryum sects. Bryum, Apalodictyon, Limbata, Leucodontium, Caespiticia, Capillaria (in part: sect. Capillaria), and Brachymenium sect. Dicranobryum, is well supported in all analyses and represents a major lineage within the family. Section Dicranobryum of Brachymenium is more closely related to section Bryum than to the other sections of Brachymenium, as are Mielichhoferia macrocarpa and M. himalayana. Species of Acidodontium form a clade with Anomobryum julaceum. The grouping of species with a rosulate gametophytic growth form suggests the presence of a 'rosulate' clade similar in circumscription to the genus Rosulabryum. Mielichhoferia macrocarpa and M. himalayana are transferred to Bryum as B. porsildii and B. caucasicum, respectively.

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In this paper, I address the "wider issues Both That Affect Floristic studies today and how They Are Likely to Develop in the Future, And The Problems That special concern in the Mediterranean region particularism. A survey of published floristic studies is given for the Mediterranean and the Middle East, and the desirability of applying electronic web-based preparation and publication of floristic and taxonomic projects is considered, with special reference to the Euro + Med PlantBase project. A Survey of Published Studies Floristic IS Given for the Mediterranean and the Middle East, and the Desirability of Applying web-based electronic preparation and publication of Floristic and Taxonomic Project is regarded, with Special Reference To The Euro + Med project PlantBase. A new paradigm for taxonomy, and a plan of action for Mediterranean floristic studies are proposed. A New Paradigm for taxonomy, and a plan of action for Mediterranean Floristic studies are Proposed.

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The Entodontaceae is characterised by erect capsules with inset and substantially reduced peristomes. Differences in peristome morphology and ornamentation delimit both genera and species within the family. The Entodontaceae, as presently recognised, consists of four genera, Entodon, Erythrodontium, Mesonodon and Pylaisiobryum, which show a variety of peristome ornamentation patterns, and exhibit differing levels of peristome reduction. This variation encompasses an unusual combination of structurally reduced peristomes, which retain massive exostome ornamentation, and residual peristome function. As part of a taxonomic revision of the family in Africa, generic patterns of peristome reduction and ornamentation are described. Inter- and intra-specific variation patterns of both the exostome and endostome have been investigated using detailed SEM studies of material from Africa and beyond. Structural reduction of the peristome is associated with high levels of intra-specific variation in peristome ornamentation patterns. Common trends in these patterns of variation are identified within the family. Putative hybrid sporophytes have been identified in Entodon, and the taxonomic implications of these observations are considered for a family where species delimitation has in the past often depended on minor variation in peristome structure or ornamentation patterns. (author abst.)

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Seven obligately anaerobic, gram-positive, rod-shaped, spore-forming organisms isolated from human sources were characterized using phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequencing showed that the strains were genetically highly related to each other (displaying >99% sequence similarity) and represent a previously unknown sub-line within the Clostridium coccoides rRNA group of organisms. Strains of the unidentified bacterium used carbohydrate as fermentable substrates, producing acetic acid and lactic acid as the major products of glucose metabolism. The closest described species to the novel bacterium corresponded to Clostridium clostridioforme, although a 16S rRNA sequence divergence of 3% demonstrated they represent different species. Genomic DNA-DNA pairing studies confirmed the separateness of the unknown species and Clostridium clostridioforme. Based on phenotypic and phylogenetic evidence, it is therefore proposed that the unknown bacterium, be classified as Clostridium bolteae sp. nov. The type strain of Clostridium bolteae is WAL 16351(T) (= ATCC(T) = BAA-613(T), CCUG(T) = 46953(T)).

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Intestinal microbial community is involved in the pathogenesis of Crohn's disease, but knowledge of its potential abnormalities has been limited by the impossibility to grow many dominant intestinal bacteria. Using sequence analysis of randomly cloned bacterial 16S ribosomal DNA, the dominant faecal species from four Crolin's disease patients and four controls were compared. Whereas marked inter-individual differences were observed in the faecal microflora of patients, three remained distantly related to controls on the basis of their operational taxonomic unit composition. Bacteroides vidgatus and closely related organisms represented the only molecular species shared by all patients and exhibited an unusually high rate of occurrence. Escherichia coli clones were isolated only in two patients with ileocolonic Crohn's disease. Moreover, numerous clones belonged to phylogenetic groups or species that are commonly not dominant in the faecal microflora of healthy subjects: Pectinatus, Sutterella, Verritcomicrobium, Fusobacterium, Clostridium disporicum, clostridium glycolicum, Clostridium ramosum, Clostridium innocuum and Clostridium perfringens. (C) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.

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A previously undescribed, Gram-positive, catalase-negative, Streptococcus-like organism originating from a European beaver (Castor fiber) was subjected to a taxonomic study. The organism displayed beta-haemolytic activity and gave a positive reaction with Lancefield group A antisera. Based on the results of biochemical testing, the organism was tentatively identified as a member of the genus Streptococcus, but it did not correspond phenotypically to any recognized species of this genus. Comparative 16S rRNA gene sequencing studies confirmed this assignment, with the bacterium forming a hitherto unknown subline within the genus. Sequence divergence values of greater than 3% from other reference streptococcal species, however, demonstrated that the unidentified coccus-shaped organism represents a hitherto unknown species. Based on phenotypic and molecular phylogenetic evidence, it is therefore proposed that the unknown organism from a beaver be classified as a novel species, Streptococcus castoreus sp. nov. The type strain is M605815/03/2(T) (=CCUG 48115(T) = CIP 108205(T)).

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Two strains of an unidentified, Gram-positive, catalase-negative, chain-forming, coccus-shaped organism recovered from seals were characterized using phenotypic and molecular taxonomic methods. Based on morphological and biochemical criteria the strains were tentatively identified as streptococci but they did not appear to correspond to any recognized species of the genus Streptococcus. Comparative 16S rRNA gene sequencing studies showed that the strains were closely related to each other and confirmed their placement in the genus Streptococcus. Sequence divergence values of > 5 % with reference streptococcal species demonstrated the organisms from seals represent a novel species. SDS-PAGE analysis of whole-cell proteins confirmed that the two organisms were closely related to each other but were different from all currently defined streptococcal species. Based on biochemical criteria, molecular chemical and molecular genetic evidence, it is proposed that the unknown isolates from seals be assigned to a novel species of the genus Streptococcus, Streptococcus marimammalium sp. nov. The type strain is M54/01/(T) (=CCUG 48494(T)=CIP 108309(T)).