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Late Bajocian to Early Bathonian ammonites, now attributed to Benatinites and Lugariceras, and Late Bathonian Hemigarantia, previously considered as cryptogenic taxa, share very similar sutural and ornamentation characters, suggesting their derivation from the stephanoceratid stock, most probably from the Cadomites-Polyplectites line. The palaeogeographical distribution of these taxa is limited to the North-Western African and European margins of Western Tethys. Palaeontologically, they represent the result of the iterative evolution rather than a poorly known lineage.  相似文献   

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The effectiveness of various dosages of different species/strains of nematodes was compared for Galleria mellonella and various pest insects that live in or pupate in soil. Neoaplectana feltiae (= carpocapsae), the only nematode species tested by most other workers, was never the most infective for any of the insect species tested and was least infective for two. All species/strains of nematode were able to kill insects of each species. The degree of infectivity of each of the nematode species/strains for different hosts varied considerably, and no one species/strain of nematode was the most infective for all insect species. This indicates the importance of testing a number of nematode species against any particular insect before commencing field evaluations for biological control.  相似文献   

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Jean Gaudant 《Geobios》1980,13(5):683-703
The study of fossil Fishes preserved in the «calcaires à Bythinies of Montmeyan, la Mourotte and Saint-Julien-le-Montagné basins (Var. France), makes possible the demonstration of their referal to the family Characidae: These Fishes, here mentioned as Eurocharax tourainei nov. gen., nov. sp., clearly differ from the Lower Eocene Characid fishes of Languedoc and Paris Basin by their set of teeth. The brackish condition of the “calcaires à Bythinies is taken into account for explaining the probable biogeographical history of these Fishes.  相似文献   

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A previously unknown association between a luminous Vibrio sp., taxonomically related to the species Vibrio harveyi and a common member of the shallow/mid water communities of the Mediterranean Sea, the hydrozoan Clytia linearis is described. All the specimens of C. linearis observed under blue light excitation showed both a natural luminescence appearing as a series of fine dots due to clytin, and a clear fluorescence on the external side of the perisarc around the colonies due to the presence of luminous bacteria. Luminous bacteria were isolated from the surface of C. linearis, their phenotypic characterization as isolates was performed by several morphological, biochemical, and cultural tests, completed with 16S rDNA sequence analysis. All the isolates were referred to a Vibrio sp. taxonomically related to V. harveyi. The association of the V. harveyi-related species with C. linearis, as already suggested for another hydroid, Aglaophenia octodonta, could be explained with the activity of these bacteria of feeding on the chitinous structures present in these hydroids. Moreover, the adhesion of the luminous bacterium (here referred to as Vibrio sp. CL1) on C. linearis may contribute to the survival of this Vibrio species in the marine environment providing a suitable growth habitat.  相似文献   

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The phenotypic and genotypic characteristics of fourteen human clinical Achromobacter strains representing four genogroups which were delineated by sequence analysis of nusA, eno, rpoB, gltB, lepA, nuoL and nrdA loci, demonstrated that they represent four novel Achromobacter species. The present study also characterized and provided two additional reference strains for Achromobacter ruhlandii and Achromobacter marplatensis, species for which, thus far, only single strains are publicly available, and further validated the use of 2.1% concatenated nusA, eno, rpoB, gltB, lepA, nuoL and nrdA sequence divergence as a threshold value for species delineation in this genus. Finally, although most Achromobacter species can be distinguished by biochemical characteristics, the present study also highlighted considerable phenotypic intraspecies variability and demonstrated that the type strains may be phenotypically poor representatives of the species. We propose to classify the fourteen human clinical strains as Achromobacter mucicolens sp. nov. (with strain LMG 26685T [=CCUG 61961T] as the type strain), Achromobacter animicus sp. nov. (with strain LMG 26690T [=CCUG 61966T] as the type strain), Achromobacter spiritinus sp. nov. (with strain LMG 26692T [=CCUG 61968T] as the type strain), and Achromobacter pulmonis sp. nov. (with strain LMG 26696T [=CCUG 61972T] as the type strain).  相似文献   

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A new gavialid from the Upper Miocene (“Huayquerian”) of Urumaco (western Venezuela) is described as Hesperogavialis cruxenti n. gen., n. sp. It is the only known South American gavialid in which, as in the Gavialidae from the Indian region, the nasals do not come into contact with the premaxillae. This ressemblance with the gavials of India is interpreted as a result of convergent evolution.  相似文献   

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Strains of Xanthomonas translucens have caused dieback in the Australian pistachio industry for the last 15 years. Such pathogenicity to a dicotyledonous woody host contrasts with that of other pathovars of X. translucens, which are characterized by their pathogenicity to monocotyledonous plant families. Further investigations, using DNA-DNA hybridization, gyrB gene sequencing and integron screening, were conducted to confirm the taxonomic status of the X. translucens pathogenic to pistachio. DNA-DNA hybridization provided a clear classification, at the species level, of the pistachio pathogen as a X. translucens. In the gyrB-based phylogeny, strains of the pistachio pathogen clustered among the X. translucens pathovars as two distinct lineages. Integron screening revealed that the cassette arrays of strains of the pistachio pathogen were different from those of other Xanthomonas species, and again distinguished two groups. Together with previously reported pathogenicity data, these results confirm that the pistachio pathogen is a new pathovar of X. translucens and allow hypotheses about its origin. The proposed name is Xanthomonas translucens pv. pistaciae pv. nov.  相似文献   

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In a survey of rhizobia associated with the native legumes in Yunnan Province, China, seven and nine strains isolated from the root nodules of Psoralea corylifolia, Sesbania cannabina and Medicago lupulina were respectively classified into the novel genomic species groups I and II in the genus Ensifer (former Sinorhizobium) based on the sequence analyses of the 16S rRNA gene. Analyses of concatenated housekeeping genes (atpD, recA and glnII) further revealed that they were distinct lineages in the genus, and group I was most similar to Ensifer terangae and Ensifer garamanticus (both with 94.2% similarity), while group II was most similar to Ensifer adhaerens (94.0%). These groups could be distinguished from closely related species by DNA–DNA relatedness, MALID-TOF MS, cellular fatty acid profiles and a series of phenotypic characters. Therefore, two novel species were proposed: Ensifer psoraleae sp. nov. (seven strains, type strain CCBAU 65732T = LMG 26835T = HAMBI 3286T) and Ensifer sesbaniae sp. nov. (nine strains, type strain CCBAU 65729T = LMG 26833T = HAMBI 3287T). They had a DNA G + C mol% (Tm) of 58.9 and 60.4, respectively. Both of the type strains formed effective nodules on common bean (Phaseolus vulgaris) and their hosts of origin. In addition, the previously described species Sinorhizobium morelense and Sinorhizobium americanum were renamed as Ensifer morelense comb. nov. and Ensifer americanum comb. nov. according to the accumulated data from different studies.  相似文献   

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Six strains of extremely halophilic and alkaliphilic euryarchaea were enriched and isolated in pure culture from surface brines and sediments of hypersaline alkaline lakes in various geographical locations with various forms of insoluble cellulose as growth substrate. The cells are mostly flat motile rods with a thin monolayer cell wall while growing on cellobiose. In contrast, the cells growing with cellulose are mostly nonmotile cocci covered with a thick external EPS layer. The isolates, designated AArcel, are obligate aerobic heterotrophs with a narrow substrate spectrum. All strains can use insoluble celluloses, cellobiose, a few soluble glucans and xylan as their carbon and energy source. They are extreme halophiles, growing within the range from 2.5 to 4.8 M total Na+ (optimum at 4 M) and obligate alkaliphiles, with the pH range for growth from 7.5 to 9.9 (optimum at 8.5–9). The core archaeal lipids of strain AArcel5T were dominated by C20–C20 dialkyl glycerol ether (DGE) (i.e. archaeol) and C20–C25 DGE in nearly equal proportion. The 16S rRNA gene analysis indicated that all six isolates belong to a single genomic species mostly related to the genera Saliphagus-Natribaculum-Halovarius. Taking together a substantial phenotypic difference of the new isolates from the closest relatives and the phylogenetic distance, it is concluded that the AArcel group represents a novel genus-level branch within the family Natrialbaceae for which the name Natronobiforma cellulositropha gen. nov., sp. nov. is proposed with AArcel5T as the type strain (JCM 31939T = UNIQEM U972T).  相似文献   

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