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  • 1.
    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.

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  • 2.
    Dussex, Nicolas
    et al.
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    von Seth, Johanna
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Knapp, Michael
    Kardailsky, Olga
    Robertson, Bruce C.
    Dalen, Love
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Complete genomes of two extinct New Zealand passerines show responses to climate fluctuations but no evidence for genomic erosion prior to extinction2019In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 15, no 9, article id 20190491Article in journal (Refereed)
    Abstract [en]

    Human intervention, pre-human climate change (or a combination of both), as well as genetic effects, contribute to species extinctions. While many species from oceanic islands have gone extinct due to direct human impacts, the effects of pre-human climate change and human settlement on the genomic diversity of insular species and the role that loss of genomic diversity played in their extinctions remains largely unexplored. To address this question, we sequenced whole genomes of two extinct New Zealand passerines, the huia (Heteralocha acutirostris) and South Island kokako (Callaeas cinereus). Both species showed similar demographic trajectories throughout the Pleistocene. However, the South Island kokako continued to decline after the last glaciation, while the huia experienced some recovery. Moreover, there was no indication of inbreeding resulting from recent mating among closely related individuals in either species. This latter result indicates that population fragmentation associated with forest clearing by Maori may not have been strong enough to lead to an increase in inbreeding and exposure to genomic erosion. While genomic erosion may not have directly contributed to their extinctions, further habitat fragmentation and the introduction of mammalian predators by Europeans may have been an important driver of extinction in huia and South Island kokako.

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  • 3.
    Ericson, Per G P
    et al.
    Swedish Museum of Natural History, Research Division.
    Anderson, Caisa Lisa
    Mayr, Gerald
    Hangin' on to our rocks 'n clocks: a reply to Brown et al2007In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 3, no 3, p. 260-261Article in journal (Other academic)
  • 4.
    Ericson, Per G P
    et al.
    Swedish Museum of Natural History, Research Division.
    Anderson, Cajsa L
    Britton, Tom
    Elzanowski, Andrzej
    Johansson, Ulf S
    Swedish Museum of Natural History, Department of Zoology.
    Källersjö, Mari
    Ohlson, Jan I
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Parsons, Thomas J
    Zuccon, Dario
    Mayr, Gerald
    Diversification of Neoaves: integration of molecular sequence data and fossils.2006In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 2, no 4, p. 543-7Article in journal (Refereed)
    Abstract [en]

    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.

  • 5.
    Ericson, Per G P
    et al.
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Irestedt, Martin
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics. Department of Bioinformatics and Genetics, Swedish Museum of Natural History, PO Box 50007, 10405, Stockholm, Sweden.
    She, Huishang
    Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
    Qu, Yanhua
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics. Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
    Genomic signatures of rapid adaptive divergence in a tropical montane species2021In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 17, no 7, p. 20210089-20210089Article in journal (Refereed)
    Abstract [en]

    Mountain regions contain extraordinary biodiversity. The environmental heterogeneity and glacial cycles often accelerate speciation and adaptation ofmontane species, but how these processes influence the genomic differentiation of these species is largely unknown. Using a novel chromosomelevel genome and population genomic comparisons, we study allopatricdivergence and selection in an iconic bird living in a tropical mountainregion in New Guinea, Archbold’s bowerbird (Amblyornis papuensis). Ourresults show that the two populations inhabiting the eastern and western Central Range became isolated ca 11 800 years ago, probably because the suitablehabitats for this cold-tolerating bird decreased when the climate got warmer.Our genomic scans detect that genes in highly divergent genomic regions areover-represented in developmental processes, which is probably associatedwith the observed differences in body size between the populations. Overall,our results suggest that environmental differences between the eastern andwestern Central Range probably drive adaptive divergence between them.

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  • 6.
    Johansson, Ulf S.
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Bowie, Rauri C.K.
    Hackett, Shannon J.
    Schulenberg, Thomas S.
    The Phylogenetic affinities of Crossley's Babbler (Mystacornis crossleyi): adding a new niche to the vanga radiation of Madagascar.2008In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 4, no 6, p. 677-680Article in journal (Refereed)
  • 7. Jønsson, Knud A
    et al.
    Fjeldså, Jon
    Ericson, Per G P
    Swedish Museum of Natural History, Research Division.
    Irestedt, Martin
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Systematic placement of an enigmatic Southeast Asian taxon Eupetes macrocerus and implications for the biogeography of a main songbird radiation, the Passerida.2007In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 3, no 3, p. 323-6Article in journal (Refereed)
    Abstract [en]

    Biogeographic connections between Australia and other continents are still poorly understood although the plate tectonics of the Indo-Pacific region is now well described. Eupetes macrocerus is an enigmatic taxon distributed in a small area on the Malay Peninsula and on Sumatra and Borneo. It has generally been associated with Ptilorrhoa in New Guinea on the other side of Wallace's Line, but a relationship with the West African Picathartes has also been suggested. Using three nuclear markers, we demonstrate that Eupetes is the sister taxon of the South African genus Chaetops, and their sister taxon in turn being Picathartes, with a divergence in the Eocene. Thus, this clade is distributed in remote corners of Africa and Asia, which makes the biogeographic history of these birds very intriguing. The most parsimonious explanation would be that they represent a relictual basal group in the Passerida clade established after a long-distance dispersal from the Australo-Papuan region to Africa. Many earlier taxonomic arrangements may have been based on assumptions about relationships with similar-looking forms in the same, or adjacent, biogeographic regions, and revisions with molecular data may uncover such cases of neglect of ancient relictual patterns reflecting past connections between the continents.

  • 8. Valdiosera, Cristina
    et al.
    Garcia, Nuria
    Dalen, Love
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Smith, Colin
    Kahlke, Ralf-Dietrich
    Liden, Kerstin
    Angerbjorn, Anders
    Arsuaga, Juan Luis
    Gotherstrom, Anders
    Typing single polymorphic nucleotides in mitochondrial DNA as a way to access Middle Pleistocene DNA2006In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 2, no 4, p. 601-603Article in journal (Refereed)
1 - 8 of 8
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