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Sökning: WFRF:(Johansson I) > Naturhistoriska riksmuseet

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1.
  • Ericson, Per G P, 1956-, et al. (författare)
  • Diversification of Neoaves : integration of molecular sequence data and fossils.
  • 2006
  • Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 2:4, s. 543-7
  • Tidskriftsartikel (refereegranskat)abstract
    • Patterns of diversification and timing of evolution within Neoaves, which includes almost 95% of all bird species, are virtually unknown. On the other hand, molecular data consistently indicate a Cretaceous origin of many neoavian lineages and the fossil record seems to support an Early Tertiary diversification. Here, we present the first well-resolved molecular phylogeny for Neoaves, together with divergence time estimates calibrated with a large number of stratigraphically and phylogenetically well-documented fossils. Our study defines several well-supported clades within Neoaves. The calibration results suggest that Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, diversified around or soon after the K/T boundary. Our results thus do not contradict palaeontological data and show that there is no solid molecular evidence for an extensive pre-Tertiary radiation of Neoaves.
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2.
  • Ericson, Per G P, 1956-, et al. (författare)
  • Higher-level phylogeny and morphological evolution of tyrant flycatchers, cotingas, manakins, and their allies (Aves : Tyrannida).
  • 2006
  • Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 40:2, s. 471-83
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite increased understanding of higher-level relationships in passerine birds in the last 15 years, the taxonomic boundaries and phylogenetic interrelationships of the major groups of the Tyrannida (including the cotingas, manakins, tityrines, and tyrant flycatchers) remain unclear. Here, we present an analysis of DNA sequence data obtained from two nuclear exons, three introns, and one mitochondrial gene for 26 genera of Tyrannida and 6 tracheophone outgroups. The analysis resulted in well-supported hypotheses about the earliest evolution within Tyrannida. The Cotingidae, Pipridae, Tityrinae (sensu) [Prum, R.O., Rice, N.H., Mobley, J.A., Dimmick, W.W., 2000. A preliminary phylogenetic hypothesis for the cotingas (Cotingidae) based on mitochondrial DNA. Auk 117, 236-241], Tyrannidae, and the tyrannid subfamiles Tyranninae and Pipromorphinae (sensu) [Sibley, C.G., Monroe, B. L. Jr., 1990. Distribution and Taxonomy of Birds of the World. Yale University Press, New Haven, CT] were all found to be reciprocally monophyletic (given the present taxon sampling). The Cotingidae and Pipridae form a clade that is the sister group to a well-supported clade including Oxyruncus, the Tityrinae, Piprites, and the Tyrannidae. Oxyruncus is the sister group to the Tityrinae, and Piprites is placed as the sister group to the Tyrannidae. The tyrannid subfamilies Tyranninae and Pipromorphinae are monophyletic sister taxa, but the relationships of Platyrinchus mystaceus to these two clades remains ambiguous. The presence of medial (=internal) cartilages in the syrinx is a synapomorphy for the Oxyruncus-Tityrinae-Piprites-Tyrannidae clade. Although morphological synapomorphies currently support the monophyly of both the Pipridae and the Cotingidae, convergences and/or reversals in morphological character states are common in Tyrannida. The relationship between Oxyruncus and the Tityrinae is congruent with additional syringeal synapomorphies and allozyme distance data. Accordingly, we propose the recognition the family Tityridae within the Tyrannida to include the genera Schiffornis, Laniisoma, Laniocera, Iodopleura, Xenopsaris, Pachyramphus, Tityra, and Oxyruncus.
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3.
  • Johansson, Ulf S., 1970-, et al. (författare)
  • A complete multilocus species phylogeny of the tits and chickadees (Aves:Paridae)
  • 2013
  • Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 69:3, s. 852-860
  • Tidskriftsartikel (refereegranskat)abstract
    • The avian family Paridae (tits and chickadees) contains c. 55 species distributed in the Palearctic, Nearctic, Afrotropics and Indomalaya. The group includes some of the most well-known and extensively studied avian species, and the evolutionary history, in particular the post-glacial colonization of the northern latitudes, has been comparably well-studied for several species. Yet a comprehensive phylogeny of the whole clade is lacking. Here, we present the first complete species phylogeny for the group based on sequence data front two nuclear introns and one mitochondrial gene for 67 taxa of parids. Our results strongly support the inclusion of the Fire-capped Tit (Cephalopyrus flammiceps), currently placed in the Remizidae, as the most basal member of the Paridae. The Yellow-browed Tit (Sylviparus modestus) and the Sultan Tit (Melanochlora sultanea) constitute the next two sequential branches whereas the remaining tits fall into two large clades, one of which contains the seed hoarding and nest excavating species. The indicated clades within these two groups are largely congruent with recent classifications, but with several unforeseen relationships, such as non-monophyly of the Sombre Tit (Poecile lugubris) and the Marsh Tit (Poecile palustris), as well as non-monophyly of both the African gray and the African black tits. Further, our results support a close relationship between the White-fronted Tit (Parus semilarvatus) and the varied Tit (Poecile varius) as well as a close relationship between the White-naped Tit (Parus nuchalis) and the Yellow-cheeked and Black-bred tits (Parus spilonotus and P. xanthogenys). Finally, Hume's Ground-tit (Pseudopodoces humilis) is found to be closely related to the Green-backed Tit (Parus monticolus) and the Great Tit (Parus major). We propose a new classification that is in accordance with this phylogeny. 
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5.
  • Johansson, Åke, et al. (författare)
  • A geochronological review of magmatism along the external margin of Columbia and in the Grenville-age orogens forming the core of Rodinia
  • 2022
  • Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268 .- 1872-7433. ; 371, s. 1-43
  • Tidskriftsartikel (refereegranskat)abstract
    • A total of 4344 magmatic U-Pb ages in the range 2300 to 800 Ma have been compiled from the Great Proterozoic Accretionary Orogen along the margin of the Columbia / Nuna supercontinent and from the subsequent Grenvillian collisional orogens forming the core of Rodinia. The age data are derived from Laurentia (North America and Greenland, n = 1212), Baltica (NE Europe, n = 1922), Amazonia (central South America, n = 625), Kalahari (southern Africa and Dronning Maud Land in East Antarctica, n = 386), and western Australia (n = 199). Laurentia, Baltica, and Amazonia (and possibly other cratons) most likely formed a ca. 10 000-km-long external active continental margin of Columbia from its assembly at ca. 1800 Ma until its dispersal at ca. 1260 Ma, after which all cratons studied were involved in the Rodinia-forming Grenvillian orogeny. However, the magmatic record is not smooth and even but highly irregular, with marked peaks and troughs, both for individual cratons and the combined data set. Magmatic peaks typically range in duration from a few tens of million years up to around hundred million years, with intervening troughs of comparable length. Some magmatic peaks are observed on multiple cratons, either by coincidence or because of paleogeographic proximity and common tectonic setting, while others are not. The best overall correlation, 0.617, is observed between Baltica and Amazonia, consistent with (but not definitive proof of) their being close neighbours in a SAMBA-like configuration at least in Columbia, and perhaps having shared the same peri-Columbian subduction system for a considerable time. Correlation factors between Laurentia and Baltica, or Laurentia and Amazonia, are below 0.14. Comparison between the Grenville Province in northeastern Laurentia and the Sveconorwegian Province in southwestern Fennoscandia (Baltica) shows some striking similarities, especially in the Mesoproterozoic, but also exhibits differences in the timing of events, especially during the final Grenville-Sveconorwegian collision, when the Sveconorwegian evolution seems to lag behind by some tens of million years. Between the other cratons, the evolution before and during the final Grenvillian collision is also largely diachronous. After 900 Ma, magmatic activity had ceased in all areas investigated, attesting to the position of most of them within the stable interior of Rodinia. 
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6.
  • Kornprobst, Jacques, et al. (författare)
  • Boris Choubert: Unrecognized visionarygeologist, pioneer of the global tectonics.
  • 2018
  • Ingår i: BSGF - Earth Science Bulletin. - : EDP Sciences. - 0037-9409 .- 1777-5817. ; 189:2, s. 1-15
  • Tidskriftsartikel (refereegranskat)abstract
    • This work is a review of Boris Choubert’s paper (1935), which was published in French under the rather devalorizing title: “Research on the Genesis of Palaeozoic and Precambrian Belts.” Despite its innovative content, this article had no impact either at the time of its publication or even later. It begins with the construction of a remarkable fit of the circum-Atlantic continents. This was based on the 1.000 meters isobath instead of the shoreline. Thirty years before Bullard et al. (1965), it demonstrated in an indisputable way the reality of the continents motion on the surface of the Earth. Therefore, Choubert designated Wegener’s “continental drift” as the main cause of tectonics. Even going beyond Wegener’s theory, he argued that this mechanism was efficient well before the formation of the Triassic Pangæa, during the whole Palaeozoic to result in the building of the Caledonian and Hercynian mountains. Although he was still encumbered by the vocabulary of the time regarding geosynclines, Boris Choubert described tectonics based on the horizontal mobility of the Precambrian continental blocks. Oddly enough, he did not apply this model to the Precambrian structures, which he attributed to the effects of the Earth’s rotation on the continental crust during its solidification. At the time of its publication, this paper was a very important step towards understanding global tectonics. Unfortunately, Choubert’s contemporaries did not generally recognize its significance.
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8.
  • Werdelin, Lars, et al. (författare)
  • Locating specimens of extinct tiger (Panthera tigris) subspecies: Caspian tiger (P. t. virgata), Javan tiger (P. t. sondaica), and Balinese tiger (P. t. balica) – including previously unpublished specimens
  • 2013
  • Ingår i: Mammal Study. - : Mammalogical Society of Japan. - 1343-4152 .- 1348-6160. ; 38, s. 187-198
  • Tidskriftsartikel (refereegranskat)abstract
    • Recent advances in multivariate statistics, and in ancient DNA techniques, have greatly increased understanding of tiger phylogeography. However, regardless of advances in analytical methodology, researchers will continue to need access to specimens for morphological measurements and sampling for genetic analysis. The tiger has become increasingly endangered, and out of the nine putative tiger subspecies, three (Javan, Balinese, and Caspian) have become extinct in the last 100 years, leaving the specimens kept in natural history collections as the only materials available for research. Frustratingly little information is widely available concerning the specimens of these extinct tiger subspecies. We conducted an extensive search for specimens of extinct tiger subspecies, and also developed a simple on-site method to assign unprovenanced and probable Indonesian specimens to either Javan/Balinese or Sumatran subspecies. We located a total of 88 Javan, 11 Balinese, and 46 Caspian tigers, including seven new Javan tigers, and three Balinese tigers that were not widely known previously. These specimens are critical for research in order to understand the intraspecific phylogeny and evolutionary history of the tiger.
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  • Resultat 1-8 av 8

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