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Sökning: WFRF:(Kvaček Jiří)

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1.
  • Libertín, Milan, et al. (författare)
  • The early land plant Cooksonia bohemica from the Pridoli, late Silurian, Barrandian area, the Czech Republic, Central Europe
  • 2022
  • Ingår i: Historical Biology. - : Taylor & Francis. - 0891-2963 .- 1029-2381. ; 35:12, s. 2504-2514
  • Tidskriftsartikel (refereegranskat)abstract
    • Cooksonia bohemica Schweitzer (= Aberlemnia bohemica (Schweitzer) Sakala, Pšenička et Kraft) from Přídolí strata of the Barrandian area in the Czech Republic is revised, and its morphology is documented in detail. The holotype bears sporangia that, although reniform, do not possess a slit that would allow valvate opening as assumed in earlier studies. Its axes do not show consistent shortening of segments towards the distal portion of the plant as is typical for Aberlemnia Gonez et Gerrienne. The axes contain tubular structures interpreted here as cells of conducting tissues. Masses of subtriangular trilete spores with equatorial crassitudo and finely microgranulate sculpture are of the Ambitisporites type. Cooksonia bohemica is compared with all species of Cooksonia Lang described previously. Additionally, comparisons are made with the related genus Aberlemnia. Based on studies of the type material of both taxa, we suggest retaining the species in Cooksonia. Cooksonia bohemica is differentiated from other taxa based on a combination of branching pattern, sporangial shape, and spore morphology. The remains are interpreted to be the sporophyte of an early land plant referable to tracheophytes based on the presence of vascular strands in its axes. A general radiation of cooksonioids away from a core region around the Rheic Ocean is proposed for the Silurian–Devonian transition.
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2.
  • Anderson, Heidi, et al. (författare)
  • (087–090) Proposal to treat the use of a hyphen in the name of a fossil-genus as an orthographical error
  • 2015
  • Ingår i: Taxon. - : International Association for Plant Taxonomy. - 0040-0262 .- 1996-8175.
  • Tidskriftsartikel (refereegranskat)abstract
    • We propose modifications to the Code such that use of a hyphen in the name of a fossil-genus is treated as an error to be corrected by deletion of the hyphen. This will circumvent the need to conserve the numerous de-hyphenated names against unused hyphenated forms. We propose changes to Art. 60 of the Code to allow this correction, and the addition of a phrase in Art. 20 to add clarity to the naming of fossil-genera.
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3.
  • Friis, Else Marie, et al. (författare)
  • The Early Cretaceous mesofossil flora of Catefica, Portugal: angiosperms
  • 2022
  • Ingår i: Fossil Imprint. - Prague : National Museum. - 2533-4050 .- 2533-4069. ; 78:2, s. 341-424
  • Tidskriftsartikel (refereegranskat)abstract
    • Angiosperm mesofossils are described from the Lower Cretaceous Almargem Formation exposed near the village of Catefica, Portugal, and are thought to be of Aptian-early Albian age. The mesofossil assemblage from Catefica is diverse and, in addition to the angiosperms described here, also contains a rich assemblage of non-angiosperm fossils, including leafy axes of bryophytes and lycopsids, lycopsid and salvinialean megaspores, and sporangia, sori and leaf fragments of ferns. Thereare also twigs, cones, cone scales, seeds and sporangia of several kinds of conifers. Other seed plants include 11 species of chlamydospermous seeds and vegetative axes related to the BEG group (Bennettiales-Erdtmanithecales-Gnetales). In terms of the number of plant fragments identified, angiosperms are most abundant in the Catefica assemblage and account for morethan half of all specimens. Angiosperms also dominate in number of species, but because the non-angiosperm fossils have notbeen studied in detail the total number of species in the flora is not yet established. Sixty-seven species of angiosperms arerecognized. Angiosperm diversity is mainly at the level of non-eudicots, including ANA-grade angiosperms, Chloranthaceae and magnoliids. Remains of chloranthoid angiosperms are especially common, both in the number of specimens and in numberof species recognized. About 40 % of the specimens, and more than 25 % of the species are chloranthoids. Remains of magnoliid angiosperms (Magnoliales, Laurales, Canellales, Piperales) are also prominent among the angiosperms. Eudicots are subordinate: only 3–4 % of all angiosperm specimens can be assigned confidently to eudicot angiosperms. Five new genera and six new species of angiosperms are established (Canrightia foveolata sp. nov., Elasmostemon paisii gen. et sp. nov., Endressistemon cateficensis gen. et sp. nov., Ibericarpus cuneiformis gen. et sp. nov., Proencistemon portugallicus gen. et sp. nov., Valvidistemon globiferus gen. et sp. nov.). Several other new taxa are also described, but not formally named.
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4.
  • Halamski, Adam (författare)
  • Late Cretaceous (Campanian) leaf and palynoflora from southern Sweden
  • 2016
  • Ingår i: Geological Society of London Special Publications. - London : Geological Society of London. - 0305-8719. ; 434, s. 207-230
  • Tidskriftsartikel (refereegranskat)abstract
    • A Late Cretaceous (Campanian) leaf megaflora from the Vomb Trough in southern Skåne, Sweden, has been investigated on the basis of collections held at the Swedish Museum of Natural History. The main plant-bearing locality is Köpinge, but single specimens originate from Högestad, Ingelstorp, Rödmölla, Svenstorps mölla and Tosterup. The fossil flora is dominated by the angiosperm (eudicot) Debeya (Dewalquea) haldemiana (Debey ex de Saporta & Marion) Halamski. Other dicots are cf. Dryophyllum sp., Ettingshausenia sp., Rarytkinia? sp., Dicotylophyllum friesii (Nilsson) comb. nov. and Salicites wahlbergii (Nilsson) Hisinger. Conifers are represented by cf. Aachenia sp. (cone scales), Pagiophyllum sp. and Cyparissidium sp. (leaves). Single poorly preserved specimens of ferns and monocots have also been identified. The terrestrial palynomorphs (the focus herein) clearly link to the megaflora, although with different relative abundances. The fern spore Cyathidites dominates along with the conifer pollen Perinopollenites elatoides and Classopollis. Angiosperm pollen comprise up to 15% of the assemblage, represented by monocolpate, tricolpate and periporate pollen and the extinct Normapolles group. The spores in the kerogen residue show a thermal alteration index (TAI) of 2+. The flora probably represents mainly a coastal lowland Debeya/conifer forest, and is similar to approximately coeval assemblages from analogous palaeo-communities described from eastern Poland, western Ukraine and Westphalia.
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5.
  • HEŘMANOVÁ, ZUZANA, et al. (författare)
  • Plant mesofossils from the Late Cretaceous Klikov Formation, the CzechRepublic
  • 2021
  • Ingår i: Fossil Imprint. - : Národní muzeum. - 2533-4050 .- 2533-4069. ; 77:2, s. 256-270
  • Tidskriftsartikel (refereegranskat)abstract
    • Late Cretaceous mesofossils are described from the Zliv-Řídká Blana locality in the South Bohemian Basins, the Czech Republic. Angiosperm remains dominate the fossil assemblage both in terms of taxonomic diversity and quantitatively, with about 65 different species based on about 1,000 specimens of flowers, fruits and seeds. There are surprisingly few nonangiosperm species in the flora, with only four specimens assigned to bryophytes, ferns and conifers. There are no megaspores of Selaginellales or Salviniales, which are otherwise common in many Cretaceous mesofossil floras. Among angiosperms, flowers and fruits assigned to the Normapolles group (Fagales) and to the Ericales are particularly prominent. In systematic composition as well as general organization and size of the angiosperm reproductive organs, the Zliv-Řídká Blana mesofossil flora is comparable to other Late Cretaceous mesofossil floras collected from various regions of Laurasia. In addition to the plant remains, the fossil assemblage also includes insect eggs and coprolites.
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6.
  • Heřmanová, Zuzana, et al. (författare)
  • Reinterpretation of fossil reproductive structures Zlivifructus microtriasseris (Normapolles complex, Fagales) from the Czech and Polish Late Cretaceous
  • 2019
  • Ingår i: Review of Palaeobotany and Palynology. - : Elsevier BV. - 0034-6667.
  • Tidskriftsartikel (refereegranskat)abstract
    • Flowers and fruits of Zlivifructus microtriasseris, originally described as Caryanthus microtriasseris from the late Turonian to Santonian of the South Bohemian Basins and the late Coniacian to early Santonian of the North Sudetic Basin, are reinterpreted here. Zlivifructus microtriasseris is represented by small, flat fruits, round in outline with persistent perianths, which are fused basally, forming the hypanthium. The hypanthium extends for more than two-thirds of the fruit. Tepals leave scars indicating their insertion. Lateral attachment scars of tepals and medial attachment scars are immediately adjacent to each other, with indistinct boundaries forming a ring. The androecium consists of four stamens. The fruit shows the unilocular nature of the nut with a single seed. Lateral faces of the fruit show two parallel ribs or ridges, running from the base of the fruit to the margin of the hypanthium. The surface of the fruit bears irregularly shaped cells. Zlivifructus microtriasseris differs from species assigned to genus Caryanthus Friis 1983 in the presence of four stamen scars, and in having two lateral ribs in the face of the fruit. Zlivifructus microtriasseris differs from the type species Zlivifructus vachae in size of the fruit; shape of the fruit; perianth and attachment scars of tepals. A probabilistic classification method to differentiate between the two fruit species based on their size is proposed.
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7.
  • Kipp, Michael A., et al. (författare)
  • Nitrogen isotopes reveal independent origins of N2-fixing symbiosis in extant cycad lineages
  • 2024
  • Ingår i: Nature Ecology and Evolution. - 2397-334X. ; 8:1, s. 57-69
  • Tidskriftsartikel (refereegranskat)abstract
    • Cycads are ancient seed plants (gymnosperms) that emerged by the early Permian. Although they were common understory flora and food for dinosaurs in the Mesozoic, their abundance declined markedly in the Cenozoic. Extant cycads persist in restricted populations in tropical and subtropical habitats and, with their conserved morphology, are often called ‘living fossils.’ All surviving taxa receive nitrogen from symbiotic N2-fixing cyanobacteria living in modified roots, suggesting an ancestral origin of this symbiosis. However, such an ancient acquisition is discordant with the abundance of cycads in Mesozoic fossil assemblages, as modern N2-fixing symbioses typically occur only in nutrient-poor habitats where advantageous for survival. Here, we use foliar nitrogen isotope ratios—a proxy for N2 fixation in modern plants—to probe the antiquity of the cycad–cyanobacterial symbiosis. We find that fossilized cycad leaves from two Cenozoic representatives of extant genera have nitrogen isotopic compositions consistent with microbial N2 fixation. In contrast, all extinct cycad genera have nitrogen isotope ratios that are indistinguishable from co-existing non-cycad plants and generally inconsistent with microbial N2 fixation, pointing to nitrogen assimilation from soils and not through symbiosis. This pattern indicates that, rather than being ancestral within cycads, N2-fixing symbiosis arose independently in the lineages leading to living cycads during or after the Jurassic. The preferential survival of these lineages may therefore reflect the effects of competition with angiosperms and Cenozoic climatic change.
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8.
  • Kvaček, Jiri, et al. (författare)
  • European Roadmap for Natural History Collections : Deliverable 3.6, Synthesis of systematic resources, SYNTHESYS, Grant no. 312253
  • 2016
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • SYNTHESYS3 consortium recognises the importance of the Societal Challenges identified by the Horizon2020 programme and relevance of natural history collections for solving problems outside the traditional and conventional fields. We have reviewed 26 Use Cases backed up by documentary evidence demonstrating how the collections, expertise and services can be used to find solutions to a range of societal challenges. The Use Case review has been made available on-line in a format which allows updating and the inclusion of additional examples. It constitutes the first element for building a roadmap for the access policy of the European natural history institutions. This will enable further discussion on the prioritisation of solutions by a wider community.
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9.
  • McLoughlin, Stephen, 1964-, et al. (författare)
  • Neutron tomography, fluorescence and transmitted light microscopy reveal new insect damage, fungi and plant organ associations in the Late Cretaceous floras of Sweden
  • 2021
  • Ingår i: GFF. - London : Taylor & Francis. - 1103-5897 .- 2000-0863. ; 143:2-3, s. 248-276
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutron tomographic reconstructions, macrophotography, transmitted light microscopy and fluorescence microscopy are employed to assess the quality of organic preservation, determine organ associations,identify insect damage, and document fungal interactions with selected Santonian–lower Campanian plant fossils from the northern Kristianstad Basin, southern Sweden. Fricia nathorstii (Conwentz) comb. nov., is proposed for a composite fossil comprising an anatomically preserved (permineralized) cupressacean conifer cone and its subtending, concealed, leafy axis (preserved asa mould) in the Ryedal Sandstone. Several other impressions of conifer and angiosperm leaf-bearing axes and isolated leaves are described under open nomenclature. Three cuticle types are described from the non-marine plant-bearing beds in the basal part of the succession exposed at Åsen, but these are only assigned to informal morphotypes pending a comprehensive review of the extensive fossil cuticle flora. Two species of ascomycote epiphyllous fungi from Åsen are established: Stomiopeltites ivoeensis sp. nov. (Micropeltidales) and Meliolinites scanicus sp. nov. (Meliolales). The latter provides an important calibration point for dating the divergence of Meliolales, being the first pre-Cenozoic representative of the order. Various additional fungal remains, including thyriothecia, scolecospores, chlamydospores, putative germlings, and hyphae, are described from the cuticular surfaces of conifer and angiosperm leaves from Åsen. Insect herbivory is expressed in the form of both margin-feeding and piercing-and-sucking damage on angiosperm leaves. The Santonian–early Campanian vegetation is inferred to have grown in strongly humid, mid-latitude, coastal plain settings based on the depositional context of the assemblages, leaf morphology, and the pervasive distribution of epiphyllous fungi.
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