Change search
Refine search result
1234567 101 - 150 of 1916
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Pasero, Marco
    Università di Pisa, Italy..
    Nuovi minerali Italiana - La approvazioni 20172018In: Revista Mineralogica Italiana, ISSN 0391-9641, Vol. 42, no 3, p. 190-197Article in journal (Other (popular science, discussion, etc.))
  • 102. Bibi, Faysal
    et al.
    Pante, Michael
    Souron, Antoine
    Stewart, Kathlyn
    Varela, Sara
    Werdelin, Lars
    Swedish Museum of Natural History, Department of Paleobiology.
    Boisserie, Jean-Renaud
    Fortelius, Mikael
    Hlusko, Leslea
    Njau, Jackson
    de la Torre, Ignacio
    Paleoecology of the Serengeti during the Oldowan-Acheulean transition at Olduvai Gorge, Tanzania: The mammal and fish evidence2017In: Journal of Human Evolution, ISSN 0047-2484, E-ISSN 1095-8606Article in journal (Refereed)
    Abstract [en]

    Eight years of excavation work by the Olduvai Geochronology and Archaeology Project (OGAP) has produced a rich vertebrate fauna from several sites within Bed II, Olduvai Gorge, Tanzania. Study of these as well as recently re-organized collections from Mary Leakey's 1972 HWK EE excavations here provides a synthetic view of the faunal community of Olduvai during Middle Bed II at ~1.7e1.4 Ma, an interval that captures the local transition from Oldowan to Acheulean technology. We expand the faunal list for this interval, name a new bovid species, clarify the evolution of several mammalian lineages, and record new local first and last appearances. Compositions of the fish and large mammal assemblages support previous indications for the dominance of open and seasonal grassland habitats at the margins of an alkaline lake. Fish diversity is low and dominated by cichlids, which indicates strongly saline conditions. The taphonomy of the fish assemblages supports reconstructions of fluctuating lake levels with mass die-offs in evaporating pools. The mammals are dominated by grazing bovids and equids. Habitats remained consistently dry and open throughout the entire Bed II sequence, with no major turnover or paleoecological changes taking place. Rather, wooded and wet habitats had already given way to drier and more open habitats by the top of Bed I, at 1.85e1.80 Ma. This ecological change is close to the age of the Oldowan-Acheulean transition in Kenya and Ethiopia, but precedes the local transition in Middle Bed II. The Middle Bed II largemammal community is much richer in species and includes a much larger number of large-bodied species (>300 kg) than the modern Serengeti. This reflects the severity of Pleistocene extinctions on African large mammals, with the loss of large species fitting a pattern typical of defaunation or ‘downsizing’ by human disturbance. However, trophic network (food web) analyses show that the Middle Bed II communitywas robust, and comparisons with the Serengeti community indicate that the fundamental structure of foodwebs remained intact despite Pleistocene extinctions. The presence of a generalized meateating hominin in the Middle Bed II community would have increased competition among carnivores and vulnerability among herbivores, but the high generality and interconnectedness of the Middle Bed II food web suggests this community was buffered against extinctions caused by trophic interactions.

  • 103. Bicknell, Russell D.C.
    et al.
    Paterson, John, R.
    Caron, Jean-Bernhard
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    The gnathobasic spine microstructure of recent and Silurian chelicerates and the Cambrian artiopodan Sidneyia: Functional and evolutionary implications2018In: Arthropod structure & development, ISSN 1467-8039, E-ISSN 1873-5495, Vol. 47, p. 12-24Article in journal (Refereed)
    Abstract [en]

    Gnathobasic spines are located on the protopodal segments of the appendages of various euarthropod taxa, notably chelicerates. Although they are used to crush shells and masticate soft food items, the microstructure of these spines are relatively poorly known in both extant and extinct forms. Here we compare the gnathobasic spine microstructures of the Silurian eurypterid Eurypterus tetragonophthalmus from Estonia and the Cambrian artiopodan Sidneyia inexpectans from Canada with those of the Recent xiphosuran chelicerate Limulus polyphemus to infer potential variations in functional morphology through time. The thickened fibrous exocuticle in L. polyphemus spine tips enables effective prey mastication and shell crushing, while also reducing pressure on nerve endings that fill the spine cavities. The spine cuticle of E. tetragonophthalmus has a laminate structure and lacks the fibrous layers seen in L. polyphemus spines, suggesting that E. tetragonophthalmus may not have been capable of crushing thick shells, but a durophagous habit cannot be precluded. Conversely, the cuticle of S. inexpectans spines has asimilar fibrous microstructure to L. polyphemus, suggesting that S. inexpectans was a competent shell crusher. This conclusion is consistent with specimens showing preserved gut contents containing various shelly fragments. The shape and arrangement of the gnathobasic spines is similar for both L. polyphemusand S. inexpectans, with stouter spines in the posterior cephalothoracic or trunk appendages, respectively.This differentiation indicates that crushing occurs posteriorly, while the gnathobases on anterior appendages continue mastication and push food towards and into the mouth. The results of recent phylogenetic analyses that considered both modern and fossil euarthropod clades show that xiphosurans and eurypterids are united as crown-group euchelicerates, with S. inexpectans placed within more basalartiopodan clades. These relationships suggest that gnathobases with thickened fibrous exocuticle, if not homoplasious, may be plesiomorphic for chelicerates and deeper relatives within Arachnomorpha. This study shows that the gnathobasic spine microstructure best adapted for durophagy has remained remarkably constant since the Cambrian.

  • 104. Biel, Christina
    et al.
    Subias, Ignacio
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Acevedo, Rogelio
    Multi-isotope approach for the identification of metal and fluid sources of the Arroyo Rojo VMS deposit, Tierra del Fuego, Argentina2016In: Ore Geology Reviews, ISSN 0169-1368, E-ISSN 1872-7360Article in journal (Refereed)
  • 105.
    Bignert, Anders
    et al.
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Danielsson, Sara
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Ek, Caroline
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Faxneld, Suzanne
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Nyberg, Elisabeth
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Comments Concerning the National Swedish Contaminant Monitoring Programme in Marine Biota, 20172017Report (Other academic)
  • 106.
    Bignert, Anders
    et al.
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Danielsson, Sara
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Ek, Caroline
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Faxneld, Suzanne
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Nyberg, Elisabeth
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Comments concerning the National Swedish Contaminant Monitoring Programme in Marine Biota, 2017 (2016 years data)2017Report (Other academic)
  • 107.
    Bignert, Anders
    et al.
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Danielsson, Sara
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Faxneld, Suzanne
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Nyberg, Elisabeth
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Comments concerning the national Swedish contaminant monitoring programme in marine biota, 20162016Report (Other academic)
  • 108.
    Bignert, Anders
    et al.
    Swedish Museum of Natural History, Department of.
    Danielsson, Sara
    Swedish Museum of Natural History, Department of.
    Faxneld, Suzanne
    Swedish Museum of Natural History, Department of.
    Nyberg, Elisabeth
    Swedish Museum of Natural History, Department of.
    Vasileiou, Maria
    Swedish Museum of Natural History, Department of.
    Fång, Johan
    Swedish Museum of Natural History, Department of.
    Dahlgren, Henrik
    Swedish Museum of Natural History, Department of.
    Kylberg, Eva
    Swedish Museum of Natural History, Department of.
    Staveley Öhlund, Jill
    Swedish Museum of Natural History, Department of.
    Jones, Douglas
    Swedish Museum of Natural History, Department of.
    Stenström, Malin
    Swedish Museum of Natural History, Department of.
    Berger, Urs
    Stockholms universitet.
    Alsberg, Tomas
    Stockholms universitet.
    Kärsrud, Anne-Sofie
    Stockholms universitet.
    Sundbom, Marcus
    Stockholms universitet.
    Holm, Karin
    Stockholms universitet.
    Eriksson, Ulla
    Stockholms universitet.
    Egebäck, Anna-Lena
    Stockholms universitet.
    Haglund, Peter
    Umeå universitet.
    Kaj, Lennart
    IVL.
    Comments concerning the national Swedish contaminant monitoring programme in marine biota, 20152015Report (Other academic)
  • 109.
    Bignert, Anders
    et al.
    Swedish Museum of Natural History, Department of.
    Eriksson, Ulla
    Stockholm university.
    Nyberg, Elisabeth
    Swedish Museum of Natural History, Department of.
    Miller, Aroha
    Swedish Museum of Natural History, Department of.
    Danielsson, Sara
    Swedish Museum of Natural History, Department of.
    Consequences of using pooled versus individual samples for designingenvironmental monitoring sampling strategies2014In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, no 94, p. 177-182Article in journal (Refereed)
  • 110.
    Bignert, Anders
    et al.
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Helander, Björn
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Monitoring of contaminants and their effects on the common Guillemot and the White-tailed sea eagle2015In: Journal of Ornithology = Journal fur Ornithologie, ISSN 0021-8375, E-ISSN 1439-0361Article in journal (Refereed)
  • 111.
    Bindi, Luca
    et al.
    Università degli Studi di Firenze.
    Holtstam, Dan
    Swedish Museum of Natural History, Department of Geology.
    Fantappiè, Giulia
    Università degli Studi di Firenze.
    Andersson, Ulf B
    Luossavaara-Kiirunavaara AB.
    Bonazzi, Paola
    Università degli Studi di Firenze.
    Ferriperbøeite-(Ce), [CaCe3]å=4[Fe3+Al2Fe2+]å=4[Si2O7][SiO4]3O(OH)2, a new mineral of the gatelite supergroup, from the Nya Bastnäs Fe-Cu-REE deposit, Västmanland, Sweden.2018In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 30, p. 537-544Article in journal (Refereed)
  • 112. Bingen, B.
    et al.
    Corfu, F.
    Stein, H.J.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    U-Pb geochronology of the syn-orogenic Knaben molybdenum deposits, Sveconorwegian orogen, Norway2015In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 152, p. 537-556Article in journal (Refereed)
    Abstract [en]

    Paired isotope dilution – thermal ionization mass spectrometry (ID-TIMS) and secondary ion mass spectrometry (SIMS) zircon U–Pb data elucidate geochronological relations in the historically important Knaben molybdenum mining district, Sveconorwegian Orogen, south Norway. This polyphase district provided c. 8.5 Mt of ore with a grade of 0.2%. It consists of mineralized quartz veins, silica-rich gneiss, pegmatites and aplites associated with a heterogeneous, locally sulphide-bearing, amphibolites facies gneiss called Knaben Gneiss, and hosted in a regional-scale monotonous, commonly weakly foliated, granitic gneiss. An augen gneiss at the Knaben I deposit yields a 1257±6 Ma magmatic zircon age, dating the pre-Sveconorwegian protolith of the Knaben Gneiss. Mineralized and non-mineralized granitic gneiss samples at the Knaben II and Kvina deposits contain some 1488–1164 Ma inherited zircon and yield consistent intrusion ages of 1032±4, 1034±6 and 1036±6 Ma. This age links magmatism in the district to the regional 1050–1020 Ma Sirdal I-type granite suite, corresponding to voluminous crustal melting during the Sveconorwegian orogeny. A high-U, low-Th/U zircon rim is present in all samples. It defines several age clusters between 1039±6 and 1009±7 Ma, peaking at c. 1016 Ma and overlapping with a monazite age of 1013±5 Ma. The rim records protracted hydrothermal activity, which started during the main magmatic event and outlasted it. This process was coeval with regional high-grade Sveconorwegian metamorphism. Molybdenum deposition probably started during this event when silica-rich mineralizing fluids or hydrous magmas were released from granite magma batches. An analogy between the Knaben district and shallow, short-lived porphyry Mo deposits is inappropriate.

  • 113. Bingen, B.
    et al.
    Solli, A.
    Viola, G.
    Torgersen, E.
    Sandstad, J.S.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Røhr, T.
    Ganerød, M.
    Nasuti, A.
    Geochronology of the Palaeoproterozoic Kautokeino Greenstone Belt, Finnmark, Norway: Tectonic implications in a Fennoscandia context.2015In: Norwegian Journal of Geology, Vol. 95, p. 365-396Article in journal (Refereed)
    Abstract [en]

    Zircon U–Pb geochronological data in 18 samples from Finnmarksvidda and one sample from the Repparfjord Tectonic Window, northern Norway, constrain the evolution of the Palaeoproterozoic Kautokeino Greenstone Belt and neighbouring units in a Fennoscandia context. The Jergul Complex is an Archaean cratonic block of Karelian affinity, made of variably gneissic, tonalite–trondhjemite–granodiorite–granite plutonic rocks formed between 2975 ± 10 and 2776 ± 6 Ma. It is associated with the Archaean Goldenvárri greenstone–schist formation. At the base of the Kautokeino Greenstone Belt, the Masi Formation is a typical Jatulian quartzite, hosting a Haaskalehto-type, albite–magnetite-rich, mafic sill dated at 2220 ± 7 Ma. The Likčá and Čáskejas formations represent the main event of basaltic magmatism. A synvolcanic metagabbro dates this magmatism at 2137 ± 5 Ma. The geochemical and Nd isotopic signature of the Čáskejas Formation (eNd = +2.2 ± 1.7) is remarkably similar to coeval dykes intruding the Archaean Karelian Craton in Finland and Russia (eNd = +2.5 ± 1.0). The Čáskejas Formation can be correlated with the Kvenvik Formation in the Alta–Kvænangen Tectonic Window. Two large granite plutons yield ages of 1888 ± 7 and 1865 ± 8 Ma, and provide a maximum age for shearing along two prominent NNW–SSE-oriented shear zones recording Svecokarelian transpression. The Bidjovagge Au–Cu deposit formed around 1886 to 1837 Ma and is also related to this NNW–SSE-oriented shear system. The Ráiseatnu Complex is mainly composed of granitic gneisses formed between 1868 ± 13 and 1828 ± 5 Ma, and containing metasediment rafts and zircon xenocrysts ranging from c. 3100 to 2437 Ma. The Kautokeino Greenstone Belt and Ráiseatnu Complex are interpreted as Palaeoproterozoic, pericontinental, lithospheric domains formed during rifting between Archaean cratonic domains. They accommodated oblique convergence between the Karelian and the Norrbotten Archaean cratons during the Svecokarelian orogeny.

  • 114.
    Bisang, Irene
    Swedish Museum of Natural History, Research Division.
    SYNTHESYS offers access to European Natural History museums2014In: Gothenburg Systematikdagarna. Abstracts / [ed] Anonymous (ed), 2014Conference paper (Other academic)
    Abstract [en]

    SYNTHESYS offers access to European Natural History museums.Twenty partner institutions from 12 European countries form SYNTHESYS, and offer coordinated access to their vast natural history collections and state-of-the art analytical facilities and qualified support from in-house researchers and curators. The institutions also co-operate in Network activities to improve the collections’ management, long-term preservation and accessibility. A Joint research activity develops tools to enhance the quality of and increase access to digitalized collections and data within Natural History institutions. SYNTHESYS was initiated by CETAF and receives funding by the European Union’s Research Framework Programs. It recently  secured EC funding for a third period (SYNTHESYS3 in FP7; Grant no. 312253), which started on 1st September 2013 and lasts for four years. Scientists in based in European member or associate states apply for grants covering research costs and subsistence at one or several partner institutions with a proposal that is assessed by a committee based on scientific quality.

  • 115.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Ehrlén, Johan
    Korpelainen, Helena
    University of Helsinki.
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    No evidence of sexual niche partitioning in a dioecious moss with raresexual reproduction2015In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290Article in journal (Refereed)
    Abstract [en]

    Background and Aims. Roughly half of the species of bryophytes have separate sexes (dioecious) and half are hermaphroditic (monoecious). This variation has major consequences for the ecology and evolution of the different species. In some sexually reproducing dioecious bryophytes, sex ratio has been shown to vary with environmental conditions. This study focuses on the dioecious wetland moss Drepanocladus trifarius, which rarely produces sexual branches or sporophytes and lacks apparent secondary sex characteristics, and examines whether genetic sexes exhibit different habitat preferences, i.e. whether sexual niche partitioning occurs.

    Methods. A total of 277 shoots of D. trifarius were randomly sampled at 214 locations and 12 environmental factors were quantified at each site. Sex was assigned to the individual shoots collected in the natural environments, regardless of their reproductive status, using a specifically designed molecular marker associated with female sex.

    Key Results. Male and female shoots did not differ in shoot biomass, the sexes were randomly distributed with respect to each other, and environmental conditions at male and female sampling locations did not differ. Collectively, this demonstrates a lack of sexual niche segregation. Adult genetic sex ratio was female-biased, with 28 females for every male individual.

    Conclusions. The results show that although the sexes of D. trifarius did not differ with regard to annual growth, spatial distribution or habitat requirements, the genetic sex ratio as nevertheless significantly female-biased. This supports the notion that factors other than sex-related differences in reproductive costs and sexual dimorphism can also drive the evolution of biased sex ratios in plants

  • 116.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Ehrlén, Johan
    Persson, Christin
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    Family affiliation, sexratio and sporophyte frequency in unisexual mosses2014In: Botanical journal of the Linnean Society, ISSN 0024-4074, E-ISSN 1095-8339, Vol. 174, p. 163-172Article in journal (Refereed)
    Abstract [en]

    Patterns of sex expression and sex ratios are key features of the life histories of organisms. Bryophytes are the only haploid-dominant land plants. In contrast with seed plants, more than half of bryophyte species are dioecious, with rare sexual expression and sporophyte formation and a commonly female-biased sex ratio. We asked whether variation in sex expression, sex ratio and sporophyte frequency in ten dioecious pleurocarpous wetland mosses of two different families was best explained by assuming that character states  evolved: (1) in ancestors within the respective families or (2) at the species level as a response to recent habitat conditions. Lasso regression shrinkage identified relationships between family membership and sex ratio and sporophyte frequency, whereas environmental conditions were not correlated with any investigated reproductive trait. Sex ratio and sporophyte frequency were correlated with each other. Our results suggest that ancestry is more important than the current environment in explaining reproductive patterns at and above the species level in the studied wetland mosses, and that mechanisms controlling sex ratio and sporophyte frequency are phylogenetically conserved. Obviously, ancestry should be considered in the study of reproductive character state variation in plants.

  • 117.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Hallingbäck, Thomas
    Bryophyte Specialist Group2015Report (Other academic)
    Abstract [en]

    The Species Survival Commission (SSC), a science-based network comprising over 9,000 volunteer experts deployed across more than 130 Specialist Groups, Red List Authorities and Task Forces, all working together towards achieving the vision of “A world that values and conserves present levels of biodiversity,” presents its annual report for 2014. 

  • 118.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Hallingbäck, Tomas
    Bryophyte Specialist Group. In "2015 Annual Report of the Species Survival Commission and the Global Species Program"2016In: Species, ISSN 1016-927x, p. 70-71Article in journal (Other academic)
  • 119.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    Drepanocladus turgescens (T. Jensen) Broth. doch im Engadin2017In: Meylania, ISSN 1018-8142, Vol. 59, p. 9-13Article in journal (Other (popular science, discussion, etc.))
  • 120.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    Infraspecific sex ratio variation and its predictors in mosses – the case of the wetland moss Drepanocladus lycopodioides2015In: Botany 2015. Science and Plants for People. Abstracts. / [ed] Anonymous, 2015Conference paper (Other academic)
    Abstract [en]

    Sex ratio variation is a common but unexplained phenomenon of many species with chromosomal sex determination, including many bryophytes. Expressed sex ratio variation could be related to environmental conditions in a few mosses investigated to date. However, many bryophyte populations are non-fertile during their entire life cycle and intraspecific genetic sex ratio variation remains highly unexplored in natural populations. Drepanocladus lycopodioides, a pleurocarpous wetland moss with a distribution largely confined to Western Eurasia, rarely to occasionally forms sexual organs. It belongs to the majority of bryophytes that exhibits a female bias in expressed sex ratio. We applied a novel approach to sex individual shoots irrespective of their reproductive state using a specifically designed female-targeting molecular marker. We demonstrated that the bias in sex expression corresponds to a genetic female bias in the European adult population. Here, we investigated three regional populations of D. lycopodioides in its core distribution area. We asked whether haplotype diversity (H), sex expression (SE), genetic sex ratios, and sporophyte frequency varied within and among regions, whether these characteristics were related with each other, and / or to environmental parameters. Levels of H differed among regions and were positively related to habitat patch size. H was unequally partitioned between the sexes and was associated with estimated regional sporophyte frequency. Recorded plot-wise sporophyte frequency was generally very low in all regions. Overall genetic sex ratio was female-biased in all regions. Sex expression and genetic sex ratio varied strongly within regions (SE 0 –75%), with 27% of the plots lacking sex organs and 78% of the plots one-sexed, but differences among regions were non-significant. While no sex expression occurred in habitats deeper than 25cm, genetic sex ratio was not related to the measured environmental parameters.

  • 121.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    Males Are Not Shy in the Wetland Moss Drepanocladus lycopodioides2013In: International journal of plant sciences, ISSN 1058-5893, E-ISSN 1537-5315, Vol. 174, no 5, p. 733-739Article in journal (Refereed)
    Abstract [en]

    Premise of research. Maintenance of dioecious and monoecious sexual systems at nearly equal frequencies, infrequent sexual expression, and distinctly female-skewed sex ratios among the dioecious species are reproductive characteristics of bryophytes, which are otherwise unusual among embryophytes. Most sex ratio assessments to date have relied on gametophytes forming sexual organs, and how these reflect genetic genders is largely unresolved.

    Methodology. For the European wetland moss Drepanocladus lycopodioides, we ask whether the adult expressed sex ratio is more strongly female biased than the “true” population sex ratio based on genetically male and female plants, i.e., whether males exhibit a lower sex expression rate than females (shy males). We assess expressed sex ratio on the basis of sex expression in individually scored herbarium specimens. We directly and on a large geographic scale assess nonexpressed sex ratio, for the second time in a moss, by sexing individual shoots from nonexpressing specimens using a molecular sex marker.

    Pivotal results. On the basis of the female and male frequencies in these two data sets and the overall proportion of expressing specimens, we estimate the European population sex ratio as 2.6 : 1 (female to male). All three sex ratios are significantly female skewed and do not significantly differ from each other, indicating that there is no gender difference in sex expression rates.

    Conclusions. These results and previous data for Drepanocladus trifarius show that males are not shy in the two wetland mosses of markedly different habitats.

  • 122.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    Mass occurrence of springtails on a moss cushion – what are they doing?2015In: Melting Pot, Swedish Museum of Natural History, Abstracts: https://vega.nrm.se/vanstermenyn/forskningochsamlingar/meltingpot/2015.9654.html, 2015Conference paper (Other academic)
    Abstract [en]

    The motile spermatozoids of bryophytes can swim up to a few centimetres. They require free water to fertilize the egg of the female organs, which sit on plants separate from the males in more than 50% of the species. When the sex organs are produced on different plants, this presents a serious obstacle to successful fertilization. The problems are overcome by a variety of mechanisms. Some of the more spectacular include spermatozoid transport up to at least several decimetres by water movement, by water drops spread from splash-cups surrounding the male organs up to two meters, by ejection up to15 centimetres into the air, or by having dwarf males that grow directly on the female plants. Here we report on another special kind of spermatozoid transfer that we came across during fieldwork in 2014, namely by micro-arthropods. Bryophyte fertilization mediated by animals was suggested more than a century ago, and was recently shown to occur in experimental settings. However, our observation is likely one of the first made directly in nature.

     

     

  • 123.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    Mass-occurrence of springtails on Tortula cernua: A field-observation ofpossible animal-mediated fertilization2015In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 37Article in journal (Refereed)
  • 124.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    Sammelst du Moose oder Flechten auf deinen Auslandreisen? – Gedanken zum Nagoya-Protokoll2015In: Meylania, Vol. 55, article id 29-31Article in journal (Other academic)
  • 125.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    Cronberg, Nils
    Can the meiotic sex ratio explain the sex ratio bias in adult populations in the dioicous moss Drepanocladus lycopodioides?2017In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820Article in journal (Refereed)
  • 126.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Lienhard, Luc
    Bergamini, Ariel
    Effects of land use practices on arable bryopytes in the Swiss lowlands - a 30-year monitoring study using hornworts amodel organisms.2017Report (Other (popular science, discussion, etc.))
  • 127.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    Lienhard, Luc
    Bergamini, Ariel
    Entwicklung von Ackermoospopulation und ihren Lebensräumen im Schweizer Mittelland während der letzten 25 Jahre.: 2nd adinterim report, unpubl. Contract-number 06.0126.PZ I P083-02652017Report (Other academic)
  • 128.
    Bisang, Irene
    et al.
    Swedish Museum of Natural History, Department of Botany.
    van Rooy, Jacques
    South African National Biodiversity Institute,.
    IUCN SSC BryophyteSpecialist Group, 2016-2017 Report2018Report (Other academic)
  • 129. Biström, Olof
    et al.
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    A new species of Peschetius GUIGNOT described from Sri Lanka (Coleoptera: Dytiscidae)2015In: Koleopterologische Rundschau, Vol. 85, p. 57-60Article in journal (Refereed)
    Abstract [en]

    Peschetius taprobanicus sp.n. (Coleoptera: Dytiscidae) is described on the basis of six specimens

    collected from Sri Lanka. Distinguishing characters are given for the new species.

  • 130. Biström, Olof
    et al.
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    Two new species of the megadiverse lentic diving-beetle genus Hydrovatus (Coleoptera, Dytiscidae) described from NE Thailand.2016In: ZooKeys, ISSN 1313-2989, E-ISSN 1313-2970, no 632, p. 57-66Article in journal (Refereed)
    Abstract [en]

    Here we describe two new Hydrovatus species (Coleoptera: Dytiscidae: Hydroporinae: Hydrovatini) from the province of Khon Kaen, Isan region in NE Thailand. Hydrovatus is the third most species rich genus of diving beetles (Dytiscidae). It occurs on all continents except Antarctica and now numbers 210 currently recognized species. Both new species, Hydrovatus diversipunctatussp. n. and Hydrovatus globosussp. n., were collected at lights and are only known from the type locality "Khon Kaen" (a city and province). Diagnoses based on morphology for the separation from closely related species are given together with illustrations of male genitalia and habitus photos. We provide a determination key to Old World species of the pustulatus species group and to Oriental species of the oblongipennis species group.

  • 131. Biström, Olof
    et al.
    Nilsson, Anders N
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    Taxonomic revision of Afrotropical Laccophilus Leach, 1815 (Coleoptera, Dytiscidae).2015In: ZooKeys, ISSN 1313-2989, E-ISSN 1313-2970, no 542, p. 1-379Article in journal (Refereed)
    Abstract [en]

    The African species of the genus Laccophilus Leach, 1815, are revised, on the basis of study of adult specimens. In all, 105 species are now recognized. A phenetic character-analysis was undertaken, which resulted in a split of the genus into 17 species groups. Diagnoses and a description of each species are given together with keys for identification of species groups and species. We also provide habitus photos, illustration of male genitalia and distribution maps for all species. New species are described as follows: Laccophilus grossus sp. n. (Angola, Namibia), Laccophilus rocchii sp. n. (Tanzania, Namibia, Botswana, Mozambique), Laccophilus ferrugo sp. n. (Mozambique), Laccophilus furthi sp. n. (Madagascar), Laccophilus isamberti sp. n. (Madagascar), Laccophilus inobservatus sp. n. (Gambia, Senegal, Mali, Niger, Sudan, Chad, Ethiopia, Burkina Faso, Ivory Coast, Ghana, Nigeria, Cameroon, Zaire and Asia: Yemen), Laccophilus cryptos sp. n. (Zaire, Mozambique, Zimbabwe, Namibia, Botswana, South Africa), Laccophilus enigmaticus sp. n. (Nigeria, Sudan), Laccophilus bellus sp. n. (Benin, Nigeria), Laccophilus guentheri sp. n. (Guinea, Ghana), Laccophilus guineensis sp. n. (Guinea), Laccophilus decorosus sp. n. (Uganda), Laccophilus empheres sp. n. (Kenya), Laccophilus inconstans sp. n. (Guinea, Ivory Coast, Ghana, Nigeria, Cameroon), Laccophilus brancuccii sp. n. (Central African Republic), Laccophilus incomptus sp. n. (Cameroon), Laccophilus australis sp. n. (Tanzania, South Africa), Laccophilus minimus sp. n. (Namibia), Laccophilus eboris sp. n. (Ivory Coast), Laccophilus insularum sp. n. (Madagascar), Laccophilus occidentalis sp. n. (Gambia, Senegal, Mali, Guinea, Sierra Leone, Ivory Coast, Ghana, Benin, Nigeria, Central African Republic, Zaire) and Laccophilus transversovittatus sp. n. (Madagascar). Laccophilus restrictus Sharp, 1882, is restored as good species; not junior synonym of Laccophilus pictipennis Sharp, 1882. New synonyms are established as follows: Laccophilus continentalis Gschwendtner, 1935 = Laccophilus perplexus Omer-Cooper, 1970, syn. n., Laccophilus taeniolatus Régimbart, 1889 = Laccophilus congener Omer-Cooper, 1957, syn. n., Laccophilus adspersus Boheman, 1848 = Laccophilus vitshumbii Guignot, 1959, syn. n. = Laccophilus adspersus nigeriensis Omer-Cooper, 1970, syn. n. = Laccophilus adspersus sudanensis Omer-Cooper, 1970, syn. n., Laccophilus modestus Régimbart, 1895 = Laccophilus espanyoli Hernando, 1990, syn. n., Laccophilus flaveolus Régimbart, 1906 = Laccophilus pampinatus Guignot, 1941, syn. n., Laccophilus trilineola Régimbart, 1889 = Laccophilus simulator Omer-Cooper, 1958, syn. n., Laccophilus mediocris Guignot, 1952 = Laccophilus meii Rocchi, 2000, syn. n., Laccophilus epinephes Guignot, 1955 = Laccophilus castaneus Guignot, 1956, syn. n., Laccophilus saegeri Guignot, 1958 = Laccophilus comoensis Pederzani & Reintjes, 2002, syn. n., Laccophilus restrictus Sharp, 1882 = Laccophilus evanescens Régimbart, 1895, syn. n., Laccophilus incrassatus Gschwendtner, 1933 = Laccophilus virgatus Guignot, 1953, syn. n., Laccophilus cyclopis Sharp, 1882 = Laccophilus shephardi Omer-Cooper, 1965, syn. n., Laccophilus burgeoni Gschwendtner, 1930 = Laccophilus wittei Guignot, 1952, syn. n., Laccophilus secundus Régimbart, 1895 = Laccophilus torquatus Guignot, 1956, syn. n., Laccophilus desintegratus Régimbart, 1895 = Laccophilus sanguinosus Régimbart, 1895, syn. n. and Laccophilus flavopictus Régimbart, 1889 = Laccophilus bergeri Guignot, 1953, syn. n. = Laccophilus segmentatus Omer-Cooper, 1957, syn. n. Lectotypes are designated for the following taxa: Laccophilus productus Régimbart, 1906, Laccophilus ruficollis Zimmermann, 1919, Laccophilus sordidus Sharp, 1882, Laccophilus alluaudi Régimbart, 1899, Laccophilus pictipennis Sharp, 1882, Laccophilus wehnckei Sharp, 1882, Laccophilus continentalis Gschwendtner, 1935, Laccophilus simplicistriatus Gschwendtner, 1932, Laccophilus complicatus Sharp, 1882, Laccophilus rivulosus Klug, 1833, Laccophilus ampliatus Régimbart, 1895, Laccophilus pilitarsis Régimbart, 1906, Laccophilus adspersus Boheman, 1848, Laccophilus livens Régimbart, 1895, Laccophilus modestus Régimbart, 1895, Laccophilus nodieri Régimbart, 1895, Laccophilus flaveolus Régimbart, 1906, Laccophilus pallescens Régimbart, 1903, Laccophilus restrictus Sharp, 1882, Laccophilus vermiculosus Gerstaecker, 1867, Laccophilus mocquerysi Régimbart, 1895, Laccophilus bizonatus Régimbart, 1895, Laccophilus tschoffeni Régimbart, 1895, Laccophilus persimilis Régimbart, 1895, Laccophilus poecilus Klug, 1834, Laccophilus lateralis Sharp, 1882, Laccophilus lateralis var. polygrammus Régimbart, 1903, Laccophilus cyclopis Sharp, 1882, Laccophilus shephardi Omer-Cooper, 1965, Laccophilus conjunctus Guignot, 1950, Laccophilus grammicus Sharp, 1882, Laccophilus flavoscriptus Régimbart, 1895, Laccophilus flavosignatus Régimbart, 1895, Laccophilus brevicollis Sharp, 1882, Laccophilus secundus Régimbart, Laccophilus desintegratus Régimbart, 1895, Laccophilus gutticollis Régimbart, 1895, Laccophilus luctuosus Sharp, 1882 and Laccophilus inornatus Zimmermann, 1926. Laccophilus remex Guignot, 1952, comprises a species complex with uncertain taxonomic delimitation; the complex includes Laccophilus concisus Guignot, 1953, Laccophilus turneri Omer-Cooper, 1957 and Laccophilus praeteritus Omer-Cooper, 1957, as tentative synonyms of Laccophilus remex Guignot, 1952.

  • 132. Bjelke, Ulf
    et al.
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    Vattenytans mästare2018In: Yrfän, Vol. 2018, no 3, p. 9-13Article in journal (Other (popular science, discussion, etc.))
  • 133.
    Bjurlid, Filip
    et al.
    Örebro universitet.
    Roos, Anna
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Hagberg, J
    Temporal trends of PBDD/Fs, PCDD/Fs, PBDEs and PCBs in ringed seals from the Baltic Sea (Pusa hispida botnica) between 1974 and 20152018In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 616-617, p. 1374-1383Article in journal (Refereed)
  • 134.
    Björling, Thomas
    et al.
    Stockholms universitet.
    Noréus, Dag
    Stockholms universitet.
    Jansson, Kjell
    Stockholms universitet.
    Andersson, Magnus
    Kungliga Tekniska Högskolan.
    Leonova, Ekaterina
    Stockholms universitet.
    Edén, Mattias
    Stockholms universitet.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Häussermann, Ulrich
    Stockholms universitet.
    SrAlSiH: A polyanionic semiconductor hydride2005In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 44, p. 7269-7273Article in journal (Refereed)
  • 135. Blank, Stephan M
    et al.
    Forshage, Mattias
    Swedish Museum of Natural History, Department of Zoology.
    Case 3538: CORYNINAE Benson, 1938 (Insecta, Hymenoptera, CIMBICIDAE): proposed emendation of spelling to CORYNIDINAE to remove homonymy with CORYNIDAE Johnston, 1836 (Cnidaria, Anthoathecata)2011In: Bulletin of Zoological Nomenclature, Vol. 68, no 2, p. 113-116Article in journal (Refereed)
  • 136. Blicharska, Malgorzata
    et al.
    Andersson, Johan
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    Bjelke, Ulf
    Swedish Biodiversity Centre.
    Hilding-Rydevik, Tuija
    Johansson, Frank
    Uppsala University.
    Effects of management intensity, function and vegetation on the biodiversity in urban ponds2016In: Urban Forestry & Urban Greening, ISSN 1618-8667, E-ISSN 1610-8167, Vol. 20, p. 103-112Article in journal (Refereed)
    Abstract [en]

    Ponds are important elements of green areas in cities that help counteract the negative consequences of urbanization, by providing important habitats for biodiversity in cities and being essential nodes in the overall landscape-scale habitat network. However, there is relatively little knowledge about the impacts of pond management intensity, function and environmental variables on urban pond biodiversity. In this study we addressed this gap by investigating which factors were correlated with the level of biodiversity in urban ponds, indicated by species richness of aquatic insects, in Stockholm, Sweden. Our study did not confirm any direct link between the perceived intensity of management or function of ponds and overall biodiversity. However, it seems that management can influence particular groups of species indirectly, since we found that Trichoptera richness (Caddisflies) was highest at intermediate management intensity. We suggest that this is caused by management of vegetation, as the amount of floating and emergent vegetation was significantly correlated with both the overall species richness and the richness of Trichoptera (Caddisflies). This relationship was non-linear, since ponds with an intermediate coverage of vegetation had the highest richness. Interestingly, the amount of vegetation in the pond was significantly affected by pond function and pond management. The overall species richness and richness of Trichoptera were also positively correlated with pond size. Since we found that the pattern of relations between species richness and environmental variables differed between the insect groups we suggest that it will be difficult to provide overall design and management recommendations for ponds in urban green areas. Therefore, it is recommended that to provide high aquatic diversity of species in urban areas one should aim at promoting high diversity of different types of ponds with differing management and environmental factors that shape them.

  • 137. Blicharska, Malgorzata
    et al.
    Andersson, Johan
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    Bjelke, Ulf
    Hilding-Rydevik, Tuija
    Thomsson, Michaela
    Östh, John
    Johansson, Frank
    Uppsala University.
    Is there a relationship between socio-economic factors and biodiversity in urban ponds? A study in the city of Stockholm2017In: Urban Ecosystems, ISSN 1083-8155, E-ISSN 1573-1642, p. 1-12Article in journal (Refereed)
    Abstract [en]

    Urban small water bodies, such as ponds, are essential elements of human socio-economic landscapes. Ponds also provide important habitats for species that would otherwise not survive in the urban environment. Knowledge on the biodiversity of urban ponds and the relationship between their ecological value and factors linked to urbanization and socio-economic status is crucial for decisions on where and how to establish and manage ponds in cities to deliver maximum biodiversity benefits. Our study investigates if the pattern of urban-pond biodiversity can be related to different socio-economic factors, such as level of wealth, education or percentage of buildings of different types. Because of lack of previous studies investigating that, our study is of exploratory character and many different variables are used.We found that the biodiversity of aquatic insects was significantly negatively associated with urbanisation variables such as amount of buildings and number of residents living around ponds. This relationship did not differ depending on the spatial scale of our investigation. In contrast, we did not find a significant relationship with variables representing socio-economic status, such as education level and wealth of people. This latter result suggests that the socio-economic status of residents does not lead to any particular effect in terms of the management and function of ponds that would affect biodiversity. However, there is a need for a finer-scale investigation of the different potential mechanism in which residents in areas with differing socio-economic status could indirectly influence ponds.

  • 138. Blichert-Toft, Janne
    et al.
    Delile, Hugo
    Lee, Cin-Ty
    Stos-Gale, Zofia
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Andersen, Tom
    Huhma, Hannu
    Albaréde, Francis
    Large-scale tectonic cycles in Europe revealed by distinct Pb isotope provinces2016In: Geochemistry, Geophysics, Geosystems, ISSN 1525-2027Article in journal (Refereed)
  • 139. Bohlin, Erland
    et al.
    Hallgren, Susanne
    Åhlander, Erik
    Swedish Museum of Natural History, Department of Zoology.
    Unikt skolmuseum i Örebro hotat2014In: Dagens Nyheter, ISSN 1101-2447, no 10 september, p. Kultur 24-Article in journal (Other (popular science, discussion, etc.))
  • 140. Bohlin, Johan
    et al.
    Helander, Björn
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Lapplandsfödd havsörnshona häckar i Värmland2017In: Värmlandsornitologen, Vol. 44, p. 17-Article in journal (Other (popular science, discussion, etc.))
  • 141.
    Bohlin, Johan
    et al.
    Länsstyrelsen i Värmland.
    Helander, Björn
    Swedish Museum of Natural History, Department of.
    Örnföda. Mest braxen och gädda2014In: Värmlandsornitologen, Vol. 41, p. 10-13-Article in journal (Other (popular science, discussion, etc.))
  • 142. Bolhar, R.
    et al.
    Hofmann, A.
    Kemp, A.I.S.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Wind, S.
    Kamber, B.S.
    Juvenile crust formation in the Zimbabwe Craton deduced from the O-Hf isotopic record of 3.8-3.0 Ga detrital zircons2017In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 215, p. 432-446Article in journal (Refereed)
    Abstract [en]

    Hafnium and oxygen isotopic compositions measured in-situ on U-Pb dated zircon from Archaean sedimentary successions belonging to the 2.9–2.8 Ga Belingwean/Bulawayan groups and previously undated Sebakwian Group are used to characterize the crustal evolution of the Zimbabwe Craton prior to 3.0 Ga. Microstructural and compositional criteria were used to minimize effects arising from Pb loss due to metamorphic overprinting and interaction with low-temperature fluids. 207Pb/206Pb age spectra (concordance >90%) reveal prominent peaks at 3.8, 3.6, 3.5, and 3.35 Ga, corresponding to documented geological events, both globally and within the Zimbabwe Craton. Zircon δ18O values from +4 to +10‰ point to both derivation from magmas in equilibrium with mantle oxygen and the incorporation of material that had previously interacted with water in near-surface environments. In εHf-time space, 3.8–3.6 Ga grains define an array consistent with reworking of a mafic reservoir (176Lu/177Hf ∼0.015) that separated from chondritic mantle at ∼3.9 Ga. Crustal domains formed after 3.6 Ga depict a more complex evolution, involving contribution from chondritic mantle sources and, to a lesser extent, reworking of pre-existing crust. Protracted remelting was not accompanied by significant mantle depletion prior to 3.35 Ga. This implies that early crust production in the Zimbabwe Craton did not cause complementary enriched and depleted reservoirs that were tapped by later magmas, possibly because the volume of crust extracted and stabilised was too small to influence (asthenospheric) mantle isotopic evolution. Growth of continental crust through pulsed emplacement of juvenile (chondritic mantle-derived) melts, into and onto the existing cratonic nucleus, however, involved formation of complementary depleted subcontinental lithospheric mantle since the early Archaean, indicative of strongly coupled evolutionary histories of both reservoirs, with limited evidence for recycling and lateral accretion of arc-related crustal blocks until 3.35 Ga.

  • 143. Bollard, J.
    et al.
    Connelly, J.N.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Pringle, E.A.
    Bonal, E.A.
    Jørgensen, J.K.
    Nordlund, Å.
    Moynier, F.
    Bizzarro, M.
    Early formation of planetary building blocks inferred from Pb isotopic ages of chondrules.2017In: Science Advances, ISSN 2375-2548, Vol. 3, article id e1700407Article in journal (Refereed)
    Abstract [en]

    The most abundant components of primitive meteorites (chondrites) are millimeter-sized glassy spherical chondrules formed by transient melting events in the solar protoplanetary disk. Using Pb-Pb dates of 22 individual chondrules, we show that primary production of chondrules in the early solar system was restricted to the first million years after the formation of the Sun and that these existing chondrules were recycled for the remaining lifetime of the protoplanetary disk. This finding is consistent with a primary chondrule formation episode during the early high-mass accretion phase of the protoplanetary disk that transitions into a longer period of chondrule reworking. An abundance of chondrules at early times provides the precursor material required to drive the efficient and rapid formation of planetary objects via chondrule accretion.

  • 144.
    Bomfleur, Benjamin
    et al.
    Westfälische Wilhelms-Universität, Münster, Germany.
    Blomenkemper, Patrick
    Westfälische Wilhelms-Universität, Münster, Germany.
    Kerp, Hans
    Westfälische Wilhelms-Universität, Münster, Germany.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Polar regions of the Mesozoic–Paleogene greenhouse world as refugia for relict plant groups2018In: Transformative Paleobotany: Papers to Commemorate the Life and Legacy of Thomas N. Taylor / [ed] Krings, M., Harper, C.J., Cúneo, N.R., Rothwell, G.W., Amsterdam: Elsevier, 2018, p. 593-611Chapter in book (Refereed)
    Abstract [en]

    Throughout Earth history, plants were apparently less dramatically affected by global biotic crises than animals. Here, we present the unexpected occurrence of Dicroidium, the iconic plant fossil of the Gondwanan Triassic, in Jurassic strata of East Antarctica. The material consists of dispersed cuticles of three Dicroidium species, including the type species D. odontopteroides. These youngest occurrences complement a remarkable biogeographic pattern in the distribution of Dicroidium through time: the earliest records are from palaeoequatorial regions, whereas the last records are from polar latitudes. We summarize similar, relictual high-latitude occurrences in other plant groups, including lycopsids, various ‘seed ferns’, Bennettitales, and cheirolepid conifers, to highlight a common phenomenon: during times of global warmth, the ice-free high-latitude regions acted as refugia for relictual plant taxa that have long disappeared elsewhere. Eventually, such last surviving polar populations probably disappeared as they became outcompeted by newly emerging plant groups in the face of environmental change.

  • 145.
    Bomfleur, Benjamin
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Decombeix, Anne-Laure
    Schwendemann, Andrew
    Escapa, Ignacio
    Taylor, Edith
    Taylor, Thomas
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Habit and Ecology of the Petriellales, an Unusual Group of Seed Plants from the Triassic of Gondwana2014In: International journal of plant sciences, ISSN 1058-5893, E-ISSN 1537-5315, Vol. 175, no 9, p. 1062-1075Article in journal (Refereed)
    Abstract [en]

    Premise of research. Well-preserved Triassic plant fossils from Antarctica yield insights into the physiology of plant growth under the seasonal light regimes of warm polar forests, a type of ecosystem without any modern analogue. Among the many well-known Triassic plants from Antarctica is the enigmatic Petriellaea triangulata, a dispersed seedpod structure that is considered a possible homologue of the angiosperm carpel. However, the morphology and physiology of the plants that produced these seedpods have so far remained largely elusive.

    Methodology. Here, we describe petriellalean stems and leaves in compression and anatomical preservation that enable a detailed interpretation of the physiology and ecology of these plants.

    Pivotal results. Our results indicate that the Petriellales were diminutive, evergreen, shade-adapted perennial shrubs that colonized the understory of the deciduous forest biome of polar Gondwana. This life form is very unlike that of any other known seed-plant group of that time. By contrast, it fits remarkably well into the “dark and disturbed” niche that some authors considered to have sheltered the rise of the flowering plants some 100 Myr later.

    Conclusions. The hitherto enigmatic Petriellales are now among the most comprehensively reconstructed groups of extinct seed plants and emerge as promising candidates for elucidating the mysterious origin of the angiosperms.

  • 146.
    Bomfleur, Benjamin
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Grimm, Guido
    Swedish Museum of Natural History, Department of Paleobiology.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Osmunda pulchella sp. nov. from the Jurassic of Sweden--reconciling molecular and fossil evidence in the phylogeny of modern royal ferns (Osmundaceae)2015In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 15, no 126, p. 1-25Article in journal (Refereed)
    Abstract [en]

    Background: The classification of royal ferns (Osmundaceae) has long remained controversial. Recent molecular phylogenies indicate that Osmunda is paraphyletic and needs to be separated into Osmundastrum and Osmunda s.str. Here, however, we describe an exquisitely preserved Jurassic Osmunda rhizome (O. pulchella sp. nov.) that combines diagnostic features of both Osmundastrum and Osmunda, calling molecular evidence for paraphyly into question. We assembled a new morphological matrix based on rhizome anatomy, and used network analyses to establish phylogenetic relationships between fossil and extant members of modern Osmundaceae. We re-analysed the original molecular data to evaluate root-placement support. Finally, we integrated morphological and molecular data-sets using the evolutionary placement algorithm.

    Results: Osmunda pulchella and five additional Jurassic rhizome species show anatomical character suites intermediate between Osmundastrum and Osmunda. Molecular evidence for paraphyly is ambiguous: a previously unrecognized signal from spacer sequences favours an alternative root placement that would resolve Osmunda s.l. as monophyletic. Our evolutionary placement analysis identifies fossil species as probable ancestral members of modern genera and subgenera, which accords with recent evidence from Bayesian dating.

    Conclusions: Osmunda pulchella is likely a precursor of the Osmundastrum lineage. The recently proposed root placement in Osmundaceae—based solely on molecular data—stems from possibly misinformative outgroup signals in rbcL and atpA genes. We conclude that the seemingly conflicting evidence from morphological, anatomical, molecular, and palaeontological data can instead be elegantly reconciled under the assumption that Osmunda is indeed monophyletic.

  • 147.
    Bomfleur, Benjamin
    et al.
    Swedish Museum of Natural History, Department of Paleobiology. Westfälische Wilhelms-Universität Münster.
    Grimm, Guido
    Department fu¨r Pala¨ontologie, Universita¨t Wien, Wien, Austria.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    The fossil Osmundales (Royal Ferns)—a phylogenetic network analysis, revised taxonomy, and evolutionary classification of anatomically preserved trunks and rhizomes2017In: PeerJ, ISSN 2167-8359, E-ISSN 2167-8359, Vol. 5, article id e3433Article in journal (Refereed)
    Abstract [en]

    The Osmundales (Royal Fern order) originated in the late Paleozoic and is the most ancient surviving lineage of leptosporangiate ferns. In contrast to its low diversity today (less than 20 species in six genera), it has the richest fossil record of any extant group of ferns. The structurally preserved trunks and rhizomes alone are referable to more than 100 fossil species that are classified in up to 20 genera, four subfamilies, and two families. This diverse fossil record constitutes an exceptional source of information on the evolutionary history of the group from the Permian to the present. However, inconsistent terminology, varying formats of description, and the general lack of a uniform taxonomic concept renders this wealth of information poorly accessible. To this end, we provide a comprehensive review of the diversity of structural features of osmundalean axes under a standardized, descriptive terminology. A novel morphological character matrix with 45 anatomical characters scored for 15 extant species and for 114 fossil operational units (species or specimens) is analysed using networks in order to establish systematic relationships among fossil and extant Osmundales rooted in axis anatomy. The results lead us to propose an evolutionary classification for fossil Osmundales and a revised, standardized taxonomy for all taxa down to the rank of (sub)genus. We introduce several nomenclatural novelties: (1) a new subfamily Itopsidemoideae (Guaireaceae) is established to contain Itopsidema, Donwelliacaulis, and Tiania; (2) the thamnopteroid genera Zalesskya, Iegosigopteris, and Petcheropteris are all considered synonymous with Thamnopteris; (3) 12 species of Millerocaulis and Ashicaulis are assigned to modern genera (tribe Osmundeae); (4) the hitherto enigmatic Aurealcaulis is identified as an extinct subgenus of Plenasium; and (5) the poorly known Osmundites tuhajkulensis is assigned to Millerocaulis. In addition, we consider Millerocaulis stipabonettiorum a possible member of Palaeosmunda and Millerocaulis estipularis as probably constituting the earliest representative of the (Todea-)Leptopteris lineage (subtribe Todeinae) of modern Osmundoideae.

  • 148.
    Bomfleur, Benjamin
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Klymiuk, Ashley
    Taylor, Edith
    Taylor, Thomas
    Gulbranson, Erik
    Isbell, John
    Diverse bryophyte mesofossils from the Triassic of Antarctica2014In: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 47, no 1, p. 120-132Article in journal (Refereed)
    Abstract [en]

    Compared with the fossil record of vascular plants, bryophyte fossils are rare; this circumstance is probably related to a lower preservation potential compared with that of vascular plants. We searched for bryophyte remains in extensive collections of plant-fossil assemblages from the Triassic of Antarctica and identified three assemblages with surprisingly well-preserved bryophyte fossils. Although most bryophyte remains are too fragmented to conclusively place them in a detailed systematic context, they exhibit features sufficient to suggest the presence of at least four types of leafy bryophytes and two orders of thallose liverworts (Pallaviciniales and Metzgeriales) in the high-latitude Triassic ecosystems of Antarctica. The leafy bryophytes exhibit combinations of morphological features (e.g. keeled and entire-margined, ecostate leaves with elongated cells) that today occur in only a few small, systematically isolated groups, but were common among Palaeozoic and especially Mesozoic bryophytes. The diverse morphologies of the bryophyte fossils add further support to previous hypotheses that during warmer periods in the Earth’s history, bryophyte vegetation may have been particularly rich and diverse in high-latitude regions. Through analysis of the sedimentology and taphonomy of these assemblages, we identify a combination of key factors that may explain the preservation of bryophyte fossils in these deposits: (1) punctuated, high-energetic sedimentary events causing traumatic removal and incorporation of bryophytes into sediment-laden flood waters; (2) limited transport distance, and short period of suspension, followed by rapid settling and burial as a result of a rapidly decelerating flow discharging into a floodplain environment; and (3) early-diagenetic cementation with iron hydroxides in locally anoxic zones of the organic-rich, muddy substrate.

  • 149.
    Bomfleur, Benjamin
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Vajda, Vivi
    Lund University.
    Fossilized nuclei and chromosomes reveal 180 millionyears of genomic stasis in Royal Ferns2014In: Science, ISSN ISSN 0036-8075, Vol. 343, p. 1376-1377Article in journal (Refereed)
    Abstract [en]

    Rapidly permineralized fossils can provide exceptional insights into the evolution of life over geological time. Here, we present an exquisitely preserved, calcified stem of a royal fern (Osmundaceae) from Early Jurassic lahar deposits of Sweden in which authigenic mineral precipitation from hydrothermal brines occurred so rapidly that it preserved cytoplasm, cytosol granules, nuclei, and even chromosomes in various stages of cell division. Morphometric parameters of interphase nuclei match those of extant Osmundaceae, indicating that the genome size of these reputed “living fossils” has remained unchanged over at least 180 million years—a paramount example of evolutionary stasis.

  • 150.
    Bomfleur, Benjamin
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Ferraguti, Marco
    Dipartimento di Bioscienze, Universita` degli Studi di Milano, Milano, Italy.
    Reguero, Marcelo
    Divisio´n Paleontologı´a de Vertebrados, Museo de La Plata, La Plata, Argentina.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Fossilized spermatozoa preserved in a 50-myr-old annelid cocoon from Antarctica2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 20150431, p. 1-5Article in journal (Refereed)
    Abstract [en]

    The origin and evolution of clitellate annelids—earthworms, leeches and their relatives—is poorly understood, partly because body fossils of these delicate organisms are exceedingly rare. The distinctive egg cases (cocoons) of Clitellata, however, are relatively common in the fossil record, although their potential for phylogenetic studies has remained largely unexplored. Here, we report the remarkable discovery of fossilized spermatozoa preserved within the secreted wall layers of a 50-Myr-old clitellate cocoon from Antarctica, representing the oldest fossil animal sperm yet known. Sperm characters are highly informative for the classification of extant Annelida. The Antarctic fossil spermatozoa have several features that point to affinities with the peculiar, leech-like ‘crayfish worms’ (Branchiobdellida). We anticipate that systematic surveys of cocoon fossils coupled with advances in non-destructive analytical methods may open a new window into the evolution of minute, soft-bodied life forms that are otherwise only rarely observed in the fossil record.

1234567 101 - 150 of 1916
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf