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  • 2005-2009  (9)
  • 1995-1999  (4)
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  • 11
    ISSN: 1432-1432
    Keywords: Key words: Planktonic foraminifera — Molecular phylogenetics — Rates of substitution — Ribosomal DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Planktonic foraminifera are marine protists, whose calcareous shells form oceanic sediments and are widely used for stratigraphic and paleoenvironmental analyses. The fossil record of planktonic foraminifera is compared here to their molecular phylogeny inferred from ribosomal DNA sequences. Eighteen partial SSU rDNA sequences from species representing all modern planktonic families (Globigerinidae, Hastigerinidae, Globorotaliidae, Candeinidae) were obtained and compared to seven sequences representing the major groups of benthic foraminifera. The phylogenetic analyses indicate a polyphyletic origin for the planktonic foraminifera. The Candeinidae, the Globorotaliidae, and the clade Globigerinidae + Hastigerinidae seem to have originated independently, at different epochs in the evolution of foraminifera. Inference of their relationships, however, is limited by substitution rates of heterogeneity. Rates of SSU rDNA evolution vary from 4.0 × 10−9 substitutions/site/year in the Globigerinidae to less than 1.0 × 10−9 substitutions/site/year in the Globorotaliidae. These variations may be related to different levels of adaptation to the planktonic mode of life. A clock-like evolution is observed among the Globigerinidae, for which molecular and paleontological data are congruent. Phylogeny of the Globorotaliidae is clearly biased by rapid rates of substitution in two species (G. truncatulinoides and G. menardii). Our study reveals differences in absolute rates of evolution at all taxonomic levels in planktonic foraminifera and demonstrates their effect on phylogenetic reconstructions.
    Type of Medium: Electronic Resource
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  • 12
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    PANGAEA
    In:  Supplement to: Majewski, Wojciech; Lecroq, Beatrice; Sinniger, Frederic; Pawlowski, Jan (2007): Monothalamous foraminifera from Admiralty Bay, King George Island, West Antarctica. Polish Polar Research, 28(3), 187-210
    Publication Date: 2023-07-10
    Description: During the late 2007 austral summer, 20 sediment samples were collected in Admiralty Bay (King George Island, South Shetlands, West Antarctica) from 8 down to 254 m water-depth (mwd). The samples yielded abundant assemblage of monothalamous benthic foraminifera, belonging to at least 40 morphospecies. They constituted the first such collection from Antarctic Peninsula fjords and provided a new insight into this group's diversity and distribution. Among organic-walled taxa, Psammophaga sp., Allogromia cf. crystallifera, and three morphotypes of Gloiogullmia were especially abundant. Agglutinated forms were dominated by Hippocrepinella hirudinea, Psammosphaera spp., Lagenammina spp., and various mudballs. Although, the majority of the morphotypes were known from other high?latitude locations, somewere reported for the first time. Our quantitative data (〉125 µm) showed the greatest differences between monothalamous foraminifera assemblages at shallowest water depths above 50 mwd. The deepest assemblages from between 179 and 254 mwd, were most similar, suggesting uniform near-bottom conditions at ~200 mwd throughout the Admiralty Bay.
    Keywords: Admiralty_Bay; Allogromia cf. crystallifera; Area; Armorella cf. sphaerica; Armorella sp.; Astrammina rara; Astrammina triangularis; Astrorhiza sp.; Bathysiphon cf. argenteus; Bathysiphon cf. flexilis; Calculated; Calculated after Shannon (1948); Counting 〉125 µm fraction; Crithionina cf. granum; Crithionina sp.; Depth, bathymetric; DEPTH, sediment/rock; Distance; Dominance; Foraminifera, benthic; Foraminifera, benthic dead; Foraminifera, benthic indeterminata; Foraminifera, benthic monothalamous; Fraction; Gloiogullmia sp.; Gromiids; Hippocrepina cf. crassa; Hippocrepinella alba; Hippocrepinella hirudinea; King George Island, Antarctic Peninsula; Lagenammina spp.; LATITUDE; LONGITUDE; Micrometula sp.; MULT; Multiple investigations; Nemogullmia spp.; Number of species; Pelosina aff. sphaeriloculum; Pelosina didera; Phainogullmia cf. aurata; Psammophaga sp.; Psammosphaera spp.; Sample code/label; Sample method; Shannon Diversity Index; Tinogullmia sp.; Vanhoeffenella gaussi
    Type: Dataset
    Format: text/tab-separated-values, 1015 data points
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  • 13
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    PANGAEA
    In:  Supplement to: Brandt, Angelika; Gooday, Andrew J; Brandão, Simone N; Brix, Saskia; Brökeland, Wiebke; Cedhagen, Tomas; Choudhury, Madhumita; Cornelius, Nils; Danis, Bruno; De Mesel, Ilse; Diaz, Robert; Gillan, David C; Ebbe, Brigitte; Howe, John; Janussen, Dorte; Kaiser, Stefanie; Linse, Katrin; Malyutina, Marina; Pawlowski, Jan; Raupach, Michael R; Vanreusel, Ann (2007): First insights into the biodiversity and biogeography of the Southern Ocean deep sea. Nature, 447(7142), 307-311, https://doi.org/10.1038/nature05827
    Publication Date: 2023-10-28
    Description: Shallow marine benthic communities around Antarctica show high levels of endemism, gigantism, slow growth, longevity and late maturity, as well as adaptive radiations that have generated considerable biodiversity in some taxa1. The deeper parts of the Southern Ocean exhibit some unique environmental features, including a very deep continental shelf2 and a weakly stratified water column, and are the source for much of the deep water in the world ocean. These features suggest that deep-sea faunas around the Antarctic may be related both to adjacent shelf communities and to those in other oceans. Unlike shallow-water Antarctic benthic communities, however, little is known about life in this vast deep-sea region2, 3. Here, we report new data from recent sampling expeditions in the deep Weddell Sea and adjacent areas (748-6,348 m water depth) that reveal high levels of new biodiversity; for example, 674 isopods species, of which 585 were new to science. Bathymetric and biogeographic trends varied between taxa. In groups such as the isopods and polychaetes, slope assemblages included species that have invaded from the shelf. In other taxa, the shelf and slope assemblages were more distinct. Abyssal faunas tended to have stronger links to other oceans, particularly the Atlantic, but mainly in taxa with good dispersal capabilities, such as the Foraminifera. The isopods, ostracods and nematodes, which are poor dispersers, include many species currently known only from the Southern Ocean. Our findings challenge suggestions that deep-sea diversity is depressed in the Southern Ocean and provide a basis for exploring the evolutionary significance of the varied biogeographic patterns observed in this remote environment.
    Keywords: AWI; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; SPP1158
    Type: Dataset
    Format: application/zip, 2 datasets
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