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  • Atherton, Sarah
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology. Stockholm University.
    A taxonomic review and revisions of Microstomidae (Platyhelminthes: Macrostomorpha)2019In: PLoS ONE, E-ISSN 1932-6203, Vol. 14, no 4, article id e0212073Article in journal (Refereed)
    Abstract [en]

    Microstomidae (Platyhelminthes: Macrostomorpha) diversity has been almost entirely ignored within recent years, likely due to inconsistent and often old taxonomic literature and a general rarity of sexually mature collected specimens. Herein, we reconstruct the phylogenetic relationships of the group using both previously published and new 18S and CO1 gene sequences. We present some taxonomic revisions of Microstomidae and further describe 8 new species of Microstomum based on both molecular and morphological evidence. Finally, we briefly review the morphological taxonomy of each species and provide a key to aid in future research and identification that is not dependent on reproductive morphology. Our goal is to clarify the taxonomy and facilitate future research into an otherwise very understudied group of tiny (but important) flatworms.

  • Wahlberg, Emma
    Swedish Museum of Natural History, Department of Zoology.
    FACEPAI: a script for fast and consistent environmental DNA processing and identification2019In: BMC Ecology, ISSN 1472-6785, E-ISSN 1472-6785, Vol. 19, p. 51-Article in journal (Refereed)
  • Bonazzi, Paola
    et al.
    Università degli Studi di Firenze.
    Holtstam, Dan
    Swedish Museum of Natural History, Department of Geology.
    Bindi, Luca
    Università degli Studi di Firenze.
    Gatelite-supergroup minerals: recommended nomenclature and review2019In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 31, p. 173-181Article in journal (Refereed)
  • Whitehouse, Martin J.
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Dunkley, Daniel J.
    Kusiak, Monika A.
    Wilde, Simon A.
    On the true antiquity of Eoarchean chemofossils – assessing the claim for Earth’s oldest biogenic graphite in the Saglek Block of Labrador2019In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 323, p. 70-81Article in journal (Refereed)
    Abstract [en]

    A recent claim to have found traces of Earth’s earliest life (>3.95 Ga) utilising isotopically light carbon in graphite-bearing metapelites from the Saglek Block of northern Labrador, Canada, is re-evaluated applying rigorous geological and geochronological criteria. The establishment of these criteria in previous evaluations of early life claims from southern West Greenland and northern Canada is reviewed in order to provide a backdrop to discussion of the Saglek claim. In particular, we emphasise the importance of the scale of lithological continuity in determining the veracity of such claims, which are considerably easier to demonstrate from large, relatively less tectonised supracrustal remnants like the Isua Greenstone Belt than they are from smaller, isolated enclaves of the kind found on Akilia or the highly tectonised and imbricated unit that is found in the Saglek Block. Unambiguous field relationships between ca. 3.9 Ga tonalitic gneiss and the graphite-bearing metasediments have not been demonstrated in the literature that the Saglek claim relies upon, and earlier U-Pb-Hf isotopic studies on zircon from metasediments at one of the localities used in the claim indicate a Mesoarchean to Neoarchean time of deposition. We conclude that, irrespective of the validity of the carbon isotopic evidence, field relationships and geochronological evidence fail to demonstrate an age of >3.95 Ga for the potential traces of life.

  • Drake, Henrik
    et al.
    Roberts, Nick M. W.
    Heim, Christine
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Siljeström, Sandra
    Kooijman, Ellen
    Swedish Museum of Natural History, Department of Geology.
    Broman, Curt
    Ivarsson, Magnus
    Åström, Mats E.
    Timing and origin of natural gas accumulation in the Siljan impact structure, Sweden2019In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, no 1Article in journal (Refereed)
    Abstract [en]

    Fractured rocks of impact craters may be suitable hosts for deep microbial communities on Earth and potentially other terrestrial planets, yet direct evidence remains elusive. Here, we present a study of the largest crater of Europe, the Devonian Siljan structure, showing that impact structures can be important unexplored hosts for long-term deep microbial activity. Secondary carbonate minerals dated to 80 ± 5 to 22 ± 3 million years, and thus postdating the impact by more than 300 million years, have isotopic signatures revealing both microbial methanogenesis and anaerobic oxidation of methane in the bedrock. Hydrocarbons mobilized from matured shale source rocks were utilized by subsurface microorganisms, leading to accumulation of microbial methane mixed with a thermogenic and possibly a minor abiotic gas fraction beneath a sedimentary cap rock at the crater rim. These new insights into crater hosted gas accumulation and microbial activity have implications for understanding the astrobiological consequences of impacts.

  • Smit, M. A.
    et al.
    Scherstén, A.
    Næraa, T.
    Emo, R. B.
    Scherer, E. E.
    Sprung, P.
    Bleeker, W.
    Mezger, K.
    Maltese, A.
    Cai, Y.
    Rasbury, E. T.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Formation of Archean continental crust constrained by boron isotopes2019In: Geochemical Perspectives Letters, Vol. 12, p. 23-26Article in journal (Refereed)
    Abstract [en]

    The continental crust grew and matured compositionally during the Palaeo- to Neoarchean through the addition of juvenile tonalite-trondhjemite-granodiorite (TTG) crust. This change has been linked to the start of global plate tectonics, following the general interpretation that TTGs represent ancient analogues of arc magmas. To test this, we analysed B concentrations and isotope compositions in 3.8-2.8 Ga TTGs from different Archean terranes. The 11B/10B values and B concentrations of the TTGs, and their correlation with Zr/Hf, indicate differentiation from a common B-poor mafic source that did not undergo addition of B from seawater or seawater-altered rocks. The TTGs thus do not resemble magmatic rocks from active margins, which clearly reflect such B addition to their source. The B- and 11B-poor nature of TTGs indicates that modern style subduction may not have been a dominant process in the formation of juvenile continental crust before 2.8 Ga.

  • Curran, N. M.
    et al.
    Joy, K. H.
    Snape, J. F.
    Pernet-Fisher, J. F.
    Gilmour, J. D.
    Nemchin, A. A.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Burgess, R.
    The early geological history of the Moon inferred from ancient lunar meteorite Miller Range 133172019In: Meteoritics and Planetary Science, ISSN 1086-9379, E-ISSN 1945-5100, Vol. 54, no 7, p. 1401-1430Article in journal (Refereed)
    Abstract [en]

    Abstract Miller Range (MIL) 13317 is a heterogeneous basalt-bearing lunar regolith breccia that provides insights into the early magmatic history of the Moon. MIL 13317 is formed from a mixture of material with clasts having an affinity to Apollo ferroan anorthosites and basaltic volcanic rocks. Noble gas data indicate that MIL 13317 was consolidated into a breccia between 2610 ± 780 Ma and 1570 ± 470 Ma where it experienced a complex near-surface irradiation history for ~835 ± 84 Myr, at an average depth of ~30 cm. The fusion crust has an intermediate composition (Al2O3 15.9 wt%; FeO 12.3 wt%) with an added incompatible trace element (Th 5.4 ppm) chemical component. Taking the fusion crust to be indicative of the bulk sample composition, this implies that MIL 13317 originated from a regolith that is associated with a mare-highland boundary that is KREEP-rich (i.e., K, rare earth elements, and P). A comparison of bulk chemical data from MIL 13317 with remote sensing data from the Lunar Prospector orbiter suggests that MIL 13317 likely originated from the northwest region of Oceanus Procellarum, east of Mare Nubium, or at the eastern edge of Mare Frigoris. All these potential source areas are on the near side of the Moon, indicating a close association with the Procellarum KREEP Terrane. Basalt clasts in MIL 13317 are from a very low-Ti to low-Ti (between 0.14 and 0.32 wt%) source region. The similar mineral fractionation trends of the different basalt clasts in the sample suggest they are comagmatic in origin. Zircon-bearing phases and Ca-phosphate grains in basalt clasts and matrix grains yield 207Pb/206Pb ages between 4344 ± 4 and 4333 ± 5 Ma. These ancient 207Pb/206Pb ages indicate that the meteorite has sampled a range of Pre-Nectarian volcanic rocks that are poorly represented in the Apollo, Luna, and lunar meteorite collections. As such, MIL 13317 adds to the growing evidence that basaltic volcanic activity on the Moon started as early as ~4340 Ma, before the main period of lunar mare basalt volcanism at ~3850 Ma.

  • Stigenberg, Julia
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Peris-Felipo, Francisco Javier
    Bleichestrasse 15, Basel CH-4058, Switzerland..
    Contribution to the knowledge of Swedish Dacnusini (Hymenoptera, Braconidae: Alysiinae): checklist and seven new species records2019In: JOURNAL OF INSECT BIODIVERSITY AND SYSTEMATICS, ISSN ISSN: 2423-8112, Vol. 5, no 3, p. 221-230Article in journal (Refereed)
    Abstract [en]

    A total of seven Dacnusini (Hym., Braconidae, Alysiinae) species are recorded for the first time for Sweden: Antrusa chrysotegula (Tobias, 1986), Aristelix phaenicura (Haliday, 1839), Chorebus (Phaenolexis) caesariatus Griffiths, 1967, Chorebus (Chorebus) scabrifossa Stelfox, 1957, Coelinidea gracilis (Curtis, 1829), Eucoelinidea compressa Tobias, 1979 and Sarops rea Nixon, 1942. Moreover, the genera Aristelix Nixon, 1943, Eucoelinidea Tobias, 1979 and Sarops Nixon, 1942 are thus recorded for the first time in Sweden. Finally, a checklist of the Swedish Dacnusini species is provided.

  • Stigenberg, Julia
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Peris-Felipo, Francisco Javier
    Quicke, Donald
    Department of Biology, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, BKK 10330, Thailand.
    Belokobylskij, Sergey
    Zoological Institute, Russian Academy of Sciences, St Petersburg, 199034, Russia; Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, Warszawa 00–679, Poland..
    Revision of the Oriental subgenus Patrisaspilota Fischer, 1995 (Hymenoptera: Braconidae: Alysiinae: Orthostigma Ratzeburg, 1844) with description of a new species from Papua New Guinea2019In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, Vol. 3, p. 365-378Article in journal (Refereed)
    Abstract [en]

    A revision of all Oriental species of subgenus Patrisaspilota Fischer, 1995 of the genus Orthostigma Ratzeburg, 1844 is provided and a new species from Papua New Guinea, Orthostigma (Patrisaspilota) enduwaense sp. nov., is described and illustrated. The species name Patrisaspilota memorandum Fischer, 1995 is synonymized with Orthostigma multicarinatum Tobias, 1990. A comprehensive key to the World Patrisaspilota species is presented and all known species are re-described and illustrated.

  • Pidgeon, R. T.
    et al.
    Nemchin, A. A.
    Roberts, M. P.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Bellucci, J. J.
    Swedish Museum of Natural History, Department of Geology.
    The accumulation of non-formula elements in zircons during weathering: Ancient zircons from the Jack Hills, Western Australia2019In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 530Article in journal (Refereed)
    Abstract [en]

    In this contribution we describe the influx of non-formula elements (Fe, Ca, Al, Y, U and Th) into fractures and selected zone lamellae in zircons from Jack Hills during recent weathering and discuss the effects of this on overlapping SIMS U-Th-Pb and oxygen isotope analyses. Previous research has recognised the importance of fractures in the generation of anomalous U-Th-Pb and oxygen isotope systems. In this report we show that besides fractures specific zones in euhedrally zoned zircon can act as pathways for the influx of weathering solutions and contain a similar range of trace element materials as do the fractures. Whereas zero-age discordant U-Pb systems of Jack Hills zircons have been explained by many authors in terms of Pb loss, present results confirm conclusions of our previous study that the main discordance mechanism of Jack Hills zircons is U-Th gain, due to overlap of SIMS analyses with mineralized fractures and zone lamellae with excess weathering-fluid-deposited U and Th. We explain the anomalously light and heavy oxygen isotopes and significant OH in SIMS analyses that overlap fractures and mineralized zones as due to the presence in the fractures of Ca, Fe, Al oxides and hydroxides with complexly fractionated oxygen isotopic systems. There is a suggestion in some of the elemental maps that there has been minor dispersion of trace elements away from fractures. But SIMS U-Th-Pb and oxygen isotope analyses on parts of the zircon away from fractures and mineralized zones show no evidence of interaction with weathering-fluid, indicating that penetration of weathering fluids into the body of the zircon at the location of the SIMS spots has not occurred. Results of this study have implications for other SIMS U-Th-Pb and oxygen isotope studies of zircons from rocks that have been subjected to weathering and also for early TIMS U-Pb measurements of bulk zircon samples that show zero Ma U-Pb discordance.

  • Lyon, Ian C.
    et al.
    Kusiak, Monika A.
    Wirth, Richard
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Dunkley, Daniel J.
    Wilde, Simon A.
    Schaumlöffel, Dirk
    Malherbe, Julien
    Moore, Katie L.
    Pb nanospheres in ancient zircon yield model ages for zircon formation and Pb mobilization2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, no 1Article in journal (Refereed)
    Abstract [en]

    Nanospheres of lead (Pb) have recently been identified in zircon (ZrSiO4) with the potential to compromise the veracity of U-Pb age determinations. The key assumption that the determined age is robust against the effects of Pb mobility, as long as Pb is not lost from the zircon during subsequent geological events, is now in question. To determine the effect of nanosphere formation on age determination, and whether analysis of nanospheres can yield additional information about the timing of both zircon growth and nanosphere formation, zircons from the Napier Complex in Enderby Land, East Antarctica, were investigated by high-spatial resolution NanoSIMS (Secondary Ion Mass Spectrometry) mapping. Conventional SIMS analyses with >µm resolution potentially mixes Pb from multiple nanospheres with the zircon host, yielding variable average values and therefore unreliable ages. NanoSIMS analyses were obtained of 207Pb/206Pb in nanospheres a few nanometres in diameter that were resolved from 207Pb/206Pb measurements in the zircon host. We demonstrate that analysis for 207Pb/206Pb in multiple individual Pb nanospheres, along with separate analysis of 207Pb/206Pb in the zircon host, can not only accurately yield the age of zircon crystallization, but also the time of nanosphere formation resulting from Pb mobilization during metamorphism. Model ages for both events can be derived that are correlated due to the limited range of possible solutions that can be satisfied by the measured 207Pb/206Pb ratios of nanospheres and zircon host. For the Napier Complex zircons, this yields a model age of ca 3110 Ma for zircon formation and a late Archean model age of 2610 Ma for the metamorphism that produced the nanospheres. The Nanosphere Model Age (NMA) method constrains both the crystallization age and age of the metamorphism to ~±135 Ma, a significant improvement on errors derived from counting statistics.

  • Kemp, Anthony I.S.
    et al.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Vervoort, Jeffrey D.
    Deciphering the zircon Hf isotope systematics of Eoarchean gneisses from Greenland: Implications for ancient crust-mantle differentiation and Pb isotope controversies2019In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 250, p. 76-97Article in journal (Refereed)
    Abstract [en]

    We report a Hf isotope investigation of zircons from four Eoarchaean orthogneisses from the Godthåbsfjord region of southern West Greenland by laser ablation MC-ICPMS, to elucidate crust-mantle differentiation processes in the early Earth. Zircon crystals of all samples record a complex, multi-stage growth and disturbance history, and these discrete growth phases also exhibit disparate Lu-Hf isotope systematics. The oldest (3.84–3.82 Ga) zircon cores have tightly clustered 176Hf/177Hf ratios that are consistent with derivation of their tonalitic precursors from chondritic mantle at this time, with no evidence of input from older crustal or depleted mantle sources. Younger (3.67–3.62 Ga) zircon overgrowths have subchondritic Hf and plausibly grew from small fraction partial melts of the tonalitic host, involving variable dissolution of the older zircon cores. The Neoarchean (ca. 2.7 Ga) zircon component in some samples extends to significantly higher 176Hf/177Hf than the >3.65 Ga zircon, a feature that is interpreted to reflect addition of radiogenic Hf from the rock matrix during metamorphic zircon growth and recrystallisation at 2.7 Ga. The strongly positive εHf (3.82 Ga) values obtained by dissolution of GGU110999 zircons are interpreted to be an artifact of calculating εHf values at ages that are too old, and also from the inclusion of radiogenic younger domains in the analysed multi-grain fractions, rather than to a contribution from depleted Eoarchean mantle. Such data – from zircon grains with multiple age and isotopic components – should not be used to define the evolution of crust-mantle reservoirs. A re-interpretation of the existing Pb isotope data, incorporating the new Hf isotope constraints, posits that the protoliths to the Godthåbsfjörd gneisses were influenced by radiogenic Pb introduced as a fluid mobile component during recycling of a high-μ stagnant basaltic lid at ≥3.8 Ga. The destruction of this mafic protocrust, with attendant fluid release into chondritic mantle, may have been instrumental for the generation of stable Eoarchean tonalitic crust from ca. 3.8 Ga.

  • Hammerli, Johannes
    et al.
    Kemp, Anthony I.S.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    In situ trace element and Sm-Nd isotope analysis of accessory minerals in an Eoarchean tonalitic gneiss from Greenland: Implications for Hf and Nd isotope decoupling in Earth’s ancient rocks2019In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 524, p. 394-405Article in journal (Refereed)
    Abstract [en]

    Some of the Earth’s oldest preserved continental crustal rocks, from southern West Greenland, contain contradictory radiogenic isotope signatures, whereby Hf isotope ratios are chondritic but Nd isotope ratios are distinctly super-chondritic. Models to explain this discrepancy are speculative and variously invoke deep magma ocean crystallisation, Hf-Nd decoupling in subduction zones, or metamorphic disturbance during younger thermal events. Determining the cause of this discrepancy is essential for understanding Eoarchean crust-mantle differentiation. We employ, for the first time, micro-analysis of REE-rich accessory minerals to shed light on the Nd isotope evolution of a key tonalitic gneiss sample from southern West Greenland that displays the apparent Hf-Nd isotope decoupling. The results show that the Sm-Nd isotope system was homogenized during a metamorphic event at ca. 2690 Ma. We suggest that metamorphic reactions involving consumption and re-crystallisation of REE-bearing phases were accompanied by LREE element mobility and the loss of unradiogenic Nd, shifting the bulk rock composition to a more radiogenic Nd isotope value. Our study provides the first direct evidence that the anomalous Nd isotope signatures in some Eoarchean gneisses are artefacts of the disturbance of the Sm-Nd isotope system, and not due to extensive differentiation of the bulk silicate Earth by magma ocean crystallisation or continental crust formation.

  • Bellucci, Jeremy
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Aleshin, Matvej
    Eriksson, Mats
    Simultaneous Pu and U isotope nuclear forensics on an environmentally recovered hot particle2019In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, p. 5599-5604Article in journal (Refereed)
  • Ge, Rongfeng
    et al.
    Wilde, Simon
    Nemchin, Alexander
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Bellucci, Jeremy
    Swedish Museum of Natural History, Department of Geology.
    Erickson, Timmons
    Mechanisms and consequences of intra-crystalline enrichment of ancient radiogenic Pb in detrital Hadean zircons from the Jack Hills, Western Australia2019In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 517, p. -49Article in journal (Refereed)
  • Roszjar, J.
    et al.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Terada, K.
    Fukuda, K.
    John, T.
    Bischoff, A.
    Morishita, Y.
    Hiyagon, H.
    Chemical, microstructural and chronological record of phosphates in the Ksar Ghilane 002 enriched shergottite2019In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 245, p. 385-405Article in journal (Refereed)
    Abstract [en]

    The enriched basaltic (martian) shergottite Ksar Ghilane (KG) 002, discovered in 2010, is exceptionally rich in coexisting but discrete apatite and merrillite crystals. It has been selected to better constrain the formation conditions and post-crystallization processes, and thus the evolution of martian rocks based on Ca-phosphates. A petrological, chemical, chronological and microstructural approach using a series of high-spatial resolution techniques including Raman spectroscopy, electron microscopy (SEM, EPMA, CL-imaging) and secondary ion mass spectrometry (SIMS) analysis has been applied to a representative number of Ca-phosphate grains. Analytical results for apatite and merrillite reveal: (i) zoning in F, Cl, Br and I concentrations, (ii) elevated Cl concentrations in the range of ∼11,900–35,300 µg/g and halogen ratios, i.e., Cl/Br and Cl/I, as well as stable chlorine isotope composition, reported as δ37Cl values rel. to Standard Mean Ocean Chloride (SMOC, defined as 0‰) with a value of +0.67 ± 0.14‰ (1σ), distinguishing KG 002 phosphates from that of other enriched and depleted shergottites. The halogen and heavier δ37Cl record indicate a slightly higher degree of ∼3.5% assimilation of Cl-rich and isotopically heavier crustal reservoir on Mars when compared to other enriched shergottites. (iii) Structural investigations together with the chemical and petrological context of the grains confirm the occurrence of hydroxyl-poor merrillite, indicate weak if any alteration effects induced by metamictization, only minor structural modifications due to shock metamorphism, and absence of replacement reactions. Therefore, igneous crystallization of Ca-phosphates from a fractionated, hydrous and ferrous mantle source, rich in volatiles including the halogens and Na and lithophile rare earth-elements, and absence of interaction with crustal fluids/brines of the sample is deduced. (iv) The Pb isotopic composition of six apatite and three merrillite grains is highly unradiogenic and the 238U-206Pb record yields a phosphate crystallization time at 395 ± 240 Ma (2σ), which is similar to those of other enriched shergottites.

  • Bellucci, Jeremy
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Nemchin, Alexander
    Grange, Marion
    Collins, Gareth
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Snape, Joshua
    Norman, Marc
    Kring, David
    Terrestrial-like zircon in an Apollo 14 breccia.2019In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 510, p. 173-185Article in journal (Refereed)
  • Sałacińska, Anna
    et al.
    Kusiak, Monika A.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Dunkley, Daniel J.
    Wilde, Simon A.
    Kielman, Ross
    Król, Piotr
    Gneiss-forming events in the Saglek Block, Labrador; a reappraisal of the Uivak gneiss2019In: International journal of earth sciences, ISSN 1437-3254, E-ISSN 1437-3262, Vol. 108, no 3, p. 753-778Article in journal (Refereed)
    Abstract [en]

    The Archean gneiss complex of the Saglek Block of Labrador is a part of the North Atlantic Craton, and is correlated with southern West Greenland, both being metamorphosed during a ca. 2.7 Ga event. The main component of the complex is the Eoarchean Uivak orthogneiss, which includes lenses of the Nulliak supracrustal assemblage. Both lithologies are cut by the mafic Saglek metadykes. The Uivak gneisses have been divided into Uivak I grey gneiss and Uivak II augen gneiss. The former underwent ca. 3.6 Ga high-T metamorphism prior to the intrusion of the latter. However, the exact age, nature, and extent of Uivak II gneiss are poorly understood. We present geochemical and geochronological results for both these orthogneisses to help refine the various hypotheses that have been proposed concerning the nature of their protoliths. Magmatic ages of 3746 ± 5 and 3717 ± 6 Ma are consistent with previous estimates for the age of Uivak I gneiss. Uivak II augen gneiss from Maidmonts Island, where there is a clear intrusive relationship between the Uivak II and Uivak I gneissic protoliths, has an age of 3325 ± 3 Ma. This is similar to an homogeneous grey gneiss from St. John’s Harbour, with an age of 3318 ± 5 Ma. Grey gneiss from Big Island is distinctively younger (3219 ± 7 Ma), and equivalent to the ca. 3.24 Ga Lister gneiss. Our study shows that granitic gneisses classified as Uivak II were emplaced 200–300 million years after ca. 3.6 Ga metamorphism and deformation of the Uivak I gneiss. The igneous protolith of Uivak II gneiss pre-dates the Lister gneiss by about 100 Ma. The Uivak I and Lister gneisses are geochemically similar, and are both Tonalite–Trondhjemite–Granodiorite (TTG) gneisses, whereas the Uivak II gneiss is a granitoid partially derived from pre-existing crust. We propose abandoning the term ‘Uivak II gneiss’, and renaming ca. 3.3 Ga granitoids, after the type locality, as Maidmonts gneiss. This restricts the term ‘Uivak gneiss’ to Eoarchean TTG gneisses and removes the necessity for subdividing them into Uivak I and II.

  • Olofsson, Malin
    et al.
    Robertson, Elizabeth K.
    Edler, Lars
    Arneborg, Lars
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Ploug, Helle
    Nitrate and ammonium fluxes to diatoms and dinoflagellates at a single cell level in mixed field communities in the sea2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, no 1Article in journal (Refereed)
    Abstract [en]

    Growth of large phytoplankton is considered to be diffusion limited at low nutrient concentrations, yet their constraints and contributions to carbon (C) and nitrogen fluxes in field plankton communities are poorly quantified under this condition. Using secondary ion mass spectrometry (SIMS), we quantified cell-specific assimilation rates of C, nitrate, and ammonium in summer communities of large phytoplankton when dissolved inorganic nitrogen concentrations are low in temperate coastal regions. Chain-forming diatoms composed 6% of total particulate organic carbon, but contributed 20% of C assimilation, 54% of nitrate assimilation and 32% of ammonium assimilation within the plankton community. In contrast, large dinoflagellates composed 11% of total POC, and contributed 14% of the C assimilation, 4% of ammonium and 9% of nitrate assimilation within the plankton community. Measured cell-specific C and nitrate assimilation rate match the Redfield ratio and the maximal nitrate assimilation in Chaetoceros spp. predicted by mass transfer theory. However, average ammonium assimilation rates were 30 and 340% higher than predicted by mass transfer theory in Tripos/Ceratium and Chaetoceros, respectively, suggesting that microbial interactions in the phycosphere may facilitate substantial luxury ammonium uptake by Chaetoceros in environments with fluctuating nitrate concentrations.

  • Olofsson, Malin
    et al.
    Kourtchenko, Olga
    Zetsche, Eva-Maria
    Marchant, Hannah K.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Godhe, Anna
    Ploug, Helle
    High single-cell diversity in carbon and nitrogen assimilations by a chain-forming diatom across a century2019In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 21, no 1, p. 142-151Article in journal (Refereed)
    Abstract [en]

    Summary Almost a century ago Redfield discovered a relatively constant ratio between carbon, nitrogen and phosphorus in particulate organic matter and nitrogen and phosphorus of dissolved nutrients in seawater. Since then, the riverine export of nitrogen to the ocean has increased 20 fold. High abundance of resting stages in sediment layers dated more than a century back indicate that the common planktonic diatom Skeletonema marinoi has endured this eutrophication. We germinated unique genotypes from resting stages originating from isotope-dated sediment layers (15 and 80 years old) in a eutrophied fjord. Using secondary ion mass spectrometry (SIMS) combined with stable isotopic tracers, we show that the cell-specific carbon and nitrogen assimilation rates vary by an order of magnitude on a single-cell level but are significantly correlated during the exponential growth phase, resulting in constant assimilation quota in cells with identical genotypes. The assimilation quota varies largely between different clones independent of age. We hypothesize that the success of S. marinoi in coastal waters may be explained by its high diversity of nutrient demand not only at a clone-specific level but also at the single-cell level, whereby the population can sustain and adapt to dynamic nutrient conditions in the environment.

  • Klawonn, Isabell
    et al.
    Bonaglia, Stefano
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Littmann, Sten
    Tienken, Daniela
    Kuypers, Marcel M. M.
    Brüchert, Volker
    Ploug, Helle
    Untangling hidden nutrient dynamics: rapid ammonium cycling and single-cell ammonium assimilation in marine plankton communities2019In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 13, no 8, p. 1960-1974Article in journal (Refereed)
    Abstract [en]

    Ammonium is a central nutrient in aquatic systems. Yet, cell-specific ammonium assimilation among diverse functional plankton is poorly documented in field communities. Combining stable-isotope incubations (15N-ammonium, 15N2 and 13C-bicarbonate) with secondary-ion mass spectrometry, we quantified bulk ammonium dynamics, N2-fixation and carbon (C) fixation, as well as single-cell ammonium assimilation and C-fixation within plankton communities in nitrogen (N)-depleted surface waters during summer in the Baltic Sea. Ammonium production resulted from regenerated (≥91%) and new production (N2-fixation, ≤9%), supporting primary production by 78–97 and 2–16%, respectively. Ammonium was produced and consumed at balanced rates, and rapidly recycled within 1 h, as shown previously, facilitating an efficient ammonium transfer within plankton communities. N2-fixing cyanobacteria poorly assimilated ammonium, whereas heterotrophic bacteria and picocyanobacteria accounted for its highest consumption (~20 and ~20–40%, respectively). Surprisingly, ammonium assimilation and C-fixation were similarly fast for picocyanobacteria (non-N2-fixing Synechococcus) and large diatoms (Chaetoceros). Yet, the population biomass was high for Synechococcus but low for Chaetoceros. Hence, autotrophic picocyanobacteria and heterotrophic bacteria, with their high single-cell assimilation rates and dominating population biomass, competed for the same nutrient source and drove rapid ammonium dynamics in N-depleted marine waters.

  • Schaltegger, U
    et al.
    Nowak, A
    Ulianov, A
    Fisher, C M
    Gerdes, A
    Spikings, R
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Bindeman, I
    Hanchar, J M
    Duff, J
    Vervoort, J D
    Sheldrake, T
    Caricchi, L
    Brack, P
    Müntener, O
    Zircon Petrochronology and 40Ar/39Ar Thermochronology of the Adamello Intrusive Suite, N. Italy: Monitoring the Growth and Decay of an Incrementally Assembled Magmatic System2019In: Journal of Petrology, ISSN 0022-3530, E-ISSN 1460-2415, Vol. 60, no 4, p. 701-722Article in journal (Refereed)
    Abstract [en]

    The Adamello intrusive suite is a composite batholith in Northern Italy, with an estimated 2000 km3 volume, assembled incrementally over a time span of 10 to 12 million years. The history of crystallization has been studied in detail through laser ablation ICP-MS and SIMS U–Pb geochronology of zircon, which records prolonged crystallization of each of the different intrusive units at mid-crustal levels between 43·47 and 33·16 Ma. The magmas were episodically extracted from this storage area and ascended to the final intrusion level at ∼6 km paleo-depth. Each batch of melt cooled very rapidly down to the ambient temperature of 250°C, evidenced by distinct cooling paths recorded by amphibole, biotite and K-feldspar 40Ar/39Ar dates. The magma source area was moving from SW to NE with time, causing increasing thermal maturity in the mid-crustal reservoir. The resulting temporal trend of higher degrees of crustal assimiliation in the course of the evolution of the magmatic system can be traced through Hf and O isotopes in zircon. Rough estimates of magma emplacement rates (‘magma flux’) yield very low values in the range of 10-4 km3/yr, typical of mid-to-upper crustal plutons and increase with time. Although we cannot discern a decrease of magma flux from our own data, we anticipate that a dramatic decrease of magma flux between 33 and 31 Ma along the northern contact lead to cessation of magma emplacement.

  • McLoughlin, Stephen
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Prevec, Rose
    Department of Earth Sciences, Albany Museum, 40 Somerset Street, Makhanda, 6139, Eastern Cape, South Africa, and Department of Botany, Rhodes University, PO Box 94, Makhanda, 6140, Eastern Cape, South Africa.
    The architecture of Permian glossopterid ovuliferous reproductive organs2019In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 43, no 4, p. 480-510Article in journal (Refereed)
    Abstract [en]

    A historical account of research on glossopterid ovuliferous reproductive structures reveals starkly contrasting interpretations of their architecture and homologies from the earliest investigations. The diversity of interpretations has led to the establishment of a multitude of genera for these fossil organs, many of the taxa being synonymous. We identify a need for taxonomic revision of these genera to clearly demarcate taxa before they can be used effectively as palaeobiogeographic or biostratigraphic indices. Our assessment of fructification features based on extensive studies of adpression and permineralized fossils reveals that many of the character states for glossopterids used in previous phylogenetic analyses are erroneous. We interpret glossopterid fertiligers to have been borne in loose strobili in which individual polysperms represent fertile cladodes of diverse morphologies subtended by a vegetative leaf or bract. Polysperms within the group are variously branched or condensed with ovule placement ranging from marginal to abaxial, in some cases occurring on recurved branchlets or in cupule-like structures. Glossopterid polysperms of all types are fringed by one or two ranks of wing-like structures that may represent the remnants of megasporophylls that were, ancestrally, developed on the fertile axillary shoot. Glossopterid fertiligers have similarities to the condensed bract/ovuliferous scale complexes of conifer cones, but comparisons with Mesozoic seed-ferns are hindered by insufficient data on the arrangement and homologies of the ovulebearing organs of the latter group. Nevertheless, glossopterid polysperms differ from the ovuliferous organs of Mesozoic seed-ferns by longitudinal versus transverse folding, respectively.

  • Kenny, Gavin
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Schmieder, Martin
    Lunar and Planetary Institute – USRA, 3600 Bay Area Boulevard, Houston TX 77058, USA.
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Nemchin, Alexander
    Swedish Museum of Natural History, Department of Geology.
    Morales, Luiz
    Scientific Center for Optical and Electron Microscopy (ScopeM), HPT D 9, Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland.
    Buchner, Elmar
    HNU Neu-Ulm University of Applied Sciences, Wileystraße 1, 89231 Neu-Ulm, Germany.
    Bellucci, Jeremy
    Swedish Museum of Natural History, Department of Geology.
    Snape, Josh
    Swedish Museum of Natural History, Department of Geology.
    A new U-Pb age for shock-recrystallised zircon from the Lappajärvi impact crater, Finland, and implications for the accurate dating of impact events2019In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 245, p. 479-494Article in journal (Refereed)
  • Kenny, Gavin
    et al.
    Swedish Museum of Natural History, Department of Geology.
    O'Sullivan, Gary
    Department of Geology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland.
    Alexander, Stephen
    Department of Geology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland.
    Simms, Michael
    Department of Natural Sciences, National Museums Northern Ireland, Cultra, BT18 0EU Northern Ireland, UK.
    Chew, David
    Department of Geology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland.
    Kamber, Balz
    School of Earth, Environmental and Biological Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001, Australia.
    On the track of a Scottish impact structure: a detrital zircon and apatite provenance study of the Stac Fada Member and wider Stoer Group, northwest Scotland2019In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 156, p. 1863-1876Article in journal (Refereed)
  • Ranarilalatiana, Tolotra
    et al.
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    Discovery of a specialist Copelatinae fauna on Madagascar: highly ephemeral tropical forest floor depressions as an overlooked habitat for diving beetles (Coleoptera, Dytiscidae)2019In: ZooKeys, ISSN 1313-2989, E-ISSN 1313-2970, Vol. 871, p. 89-118Article in journal (Refereed)
    Abstract [en]

    Diving beetles are generally aquatic and live submerged in water during larval and adult stages. A few groupshave colonised hygropetric habitats and fewer species still can possibly be referred to as terrestrial. Here wedescribe six new Copelatine species that were mainly found in dry shallow forest floor depressions in the easternand northeastern lowland humid forests of Madagascar. Three new species are described in each of thetwo genera Copelatus and Madaglymbus: Copelatus amphibius sp. nov., Copelatus betampona sp. nov., Copelatuszanatanensis sp. nov., Madaglymbus kelimaso sp. nov., Madaglymbus menalamba sp. nov., and Madaglymbussemifactus sp. nov. Diagnosis, description, known distribution, ecology, and conservation notes areprovided for each species. All species are illustrated with a dorsal habitus image, ventral and lateral views ofthe male penis, and parameres. Photographs of the unusual terrestrial habitats where the species were foundare provided. Madaglymbus menalamba sp. nov. is also documented with macrophotos and videorecordingsof the terrestrial locomotion and behaviour in the field. Although these species should not be classified asterrestrial, or even semi-terrestrial Dytiscidae, they seem to be specialists of very ephemeral aquatic habitatsand stay put instead of disperse when the habitat dries up. It is hypothesised that this lifestyle and behaviouron Madagascar is restricted to the high-precipitation humid forest regions mainly in the east. It may alsorepresent a transition step, or stepping-stone, towards becoming fully terrestrial, a step that the few knownterrestrial Dytiscid taxa once passed through. It is very likely that this type of habitat is overlooked for aquaticbeetles, not only in Madagascar, and the six species herein described may be just the “tip of the iceberg”.

  • Ranarilalatiana, Tolotra
    et al.
    Raveloson Ravaomanarivo, Lala Harivelo
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    Taxonomic revision of the genus Copelatus of Madagascar (Coleoptera, Dytiscidae, Copelatinae):the non-erichsonii group species2019In: ZooKeys, ISSN 1313-2989, E-ISSN 1313-2970, Vol. 869, p. 19-90Article in journal (Refereed)
    Abstract [en]

    The genus Copelatus Erichson, 1832 (Coleoptera, Dytiscidae, Copelatinae) of Madagascar is revised intwo parts. This review is restricted to the Copelatus species that have fewer than ten elytral + one submarginalstria, including all species except those of the erichsonii species group. Both morphological andmolecular (mitochondrial COI) data are used in an integrative taxonomic approach. Thirteen speciesare recognised, of which five are described as new: Copelatus ankaratra sp. nov., Copelatus kely sp. nov.,Copelatus pseudostriatus sp. nov., Copelatus safiotra sp. nov. and Copelatus vokoka sp. nov. Copelatus unguicularisRégimbart, 1903 and Copelatus apicalis Fairmaire, 1898 are both transferred to the genus MadaglymbusShaverdo & Balke, 2008 (comb. nov.). Copelatus mimetes Guignot 1957 is a junior synonym ofthe widespread Afrotropical–Arabian Copelatus pulchellus (Klug, 1834) (syn. nov.). Copelatus marginipennis(Laporte, 1835) is reinstated (stat. nov.) as a valid species with Copelatus aldabricus Balfour-Browne,1950 and Copelatus aldabricus var. simplex Guignot, 1952 as junior synonyms (syn. nov.). We designatelectotypes for Colymbetes marginipennis Laporte, 1835 and Copelatus obtusus Boheman, 1848. Copelatusperidinus Guignot, 1955 is recorded for Madagascar for the first time and Copelatus nodieri Régimbart,1895 is rejected as a species present in Madagascar.

  • Perkins, Philip D
    et al.
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    New Myxophagan water beetles from Madagascar(Coleoptera: Torridincolidae, Hydroscaphidae)2019In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, Vol. 4657, no 1, p. 57-96Article in journal (Refereed)
    Abstract [en]

    Myxophagan water beetles from Madagascar are comprehensively revised. Holotypes of the two previously known speciesare re-described and illustrated. Six new species of Incoltorrida Steffan and one new species of Hydroscapha LeConte aredescribed and illustrated. The larvae of Incoltorrida quintacostata are illustrated and discussed. The presence of peritrichciliates of the genus Platycola Kent on specimens of Incoltorrida madagassica Steffan is discussed and illustrated.Habitus, habitats, and male genitalia are illustrated, and distributions are mapped. The following new species are described(type localities parenthetic): Incoltorrida benesculpta n. sp. (Fianarantsoa, 3.2km S Ambohimanjaka); I. galoko n. sp.(Antsiranana, Diana, Ambilobe, Antsaba, Galoko mountains ); I. magna n. sp. (Antsiranana, Diana, Ambilobe, Antsaba,Galoko mountains); I. marojejy n. sp. (Antsiranana, Sava, Marojejy National Park); I. quintacostata n. sp. (Fianarantsoa,3.5km N Ivato); I. zahamena n. sp. (Toamasina, Alaotra-Mangoro, Zahamena National Park); Hydroscapha andringitran. sp. (Fianarantsoa, Ambilavao, Sendrisoa, approx. 10km N of Andringitra National Park).

  • Stålstedt, Jeanette
    et al.
    Laydanowicz, Joanna
    Lehtinen, Pekka T
    Bergsten, Johannes
    Swedish Museum of Natural History, Department of Zoology.
    Makol, Joanna
    Checklist of terrestrial Parasitengona mites in Fennoscandia with new species- and distribution records (Acariformes: Prostigmata)2019In: Biodiversity Data Journal, ISSN 1314-2836, E-ISSN 1314-2828, Vol. 7, article id e36094Article in journal (Refereed)
    Abstract [en]

    The knowledge of terrestrial Parasitengona in Fennoscandia lies far behind that of their aquatic counterparts, the water mites (Hydrachnidia). Based on new inventories, we provide primary data and an annotated checklist of terrestrial Parasitengona in Fennoscandia including 107 species. Out of these, nineteen species are new findings for the region and five are species potentially new for science. Twenty-three species are new for Norway, fourteen for Finland and eleven for Sweden. The known recorded fauna today of terrestrial Parasitengona is 80 species for Norway, 54 for Sweden and 48 for Finland. Primary data include georeferenced locality data as well as collecting techniques and microhabitat to increase the knowledge on species' habitat requirements.

  • Harper, David
    et al.
    Hammarlund, Emma
    Topper, Timothy
    Swedish Museum of Natural History, Department of Paleobiology.
    Nielsen, Arne
    Rasmussen, Jan
    Park, Tae-Yoon
    Smith, Paul
    The Sirius Passet Lagerstätte of North Greenland: a remote window on the Cambrian Explosion2019In: Journal of the Geological Society, ISSN 0016-7649, E-ISSN 2041-479X, Vol. 176, p. 1023-1037Article in journal (Refereed)
    Abstract [en]

    The lower Cambrian Lagerstätte of Sirius Passet, Peary Land, North Greenland, is one of the oldest of the Phanerozoic exceptionally preserved biotas. The Lagerstätte evidences the escalation of numbers of new body plans and life modes that formed the basis for a modern, functionally tiered ecosystem. The fauna is dominated by predators, infaunal, benthic and pelagic, and the presence of abundant nekton, including large sweep-net feeders, suggests an ecosystem rich in nutrients. Recent discoveries have helped reconstruct digestive systems and their contents, muscle fibres, and visual and nervous systems for a number of taxa. New collections have confirmed the complex combination of taphonomic pathways associated with the biota and its potentially substantial biodiversity. These complex animal-based communities within the Buen Formation were associated with microbial matgrounds, now preserved in black mudstones deposited below storm wave base that provide insight into the shift from late Neoproterozoic (Ediacaran) to Cambrian substrates and communities. Moreover, the encasing sediment holds important data on the palaeoenvironment and the water-column chemistry, suggesting that these animal-based communities developed in conditions with very low oxygen concentrations.

  • Denk, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Hill, Robert S.
    University of Adelaide.
    Simeone, Marco C.
    Università degli Studi della Tuscia, Viterbo, Italy.
    Cannon, Chuck
    Center for Tree Science, Morton Arboretum, Lisle, IL, USA.
    Dettmann, Mary E.
    Queensland Museum, Hendra, Queensland, Australia.
    Manos, Paul S.
    Department of Biology, Duke University, Durham, NC, USA.
    Comment on “Eocene Fagaceae from Patagonia and Gondwanan legacy in Asian rainforests”2019In: Science, Vol. 366, no 6467, article id eaaz2189Article in journal (Refereed)
    Abstract [en]

    Wilf et al. (Research Articles, 7 June 2019, eaaw5139) claim that Castanopsis evolved in the Southern Hemisphere from where it spread to its modern distribution in Southeast Asia. However, extensive paleobotanical records of Antarctica and Australia lack evidence of any Fagaceae, and molecular patterns indicate shared biogeographic histories of Castanopsis, Castanea, Lithocarpus, and Quercus subgenus Cerris, making the southern route unlikely.

  • Denk, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Güner, H. Tuncay
    Swedish Museum of Natural History, Department of Paleobiology. Istanbul University Cerrahpaşa, Faculty of Forestry, Department of Forest Botany, 34473 Bahçeköy, Istanbul, Turkey.
    Bouchal, Johannes M.
    Swedish Museum of Natural History, Department of Paleobiology.
    Early Miocene climate and biomes of Turkey: Evidence from leaf fossils, dispersed pollen, and petrified wood2019In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 530, p. 236-248Article in journal (Refereed)
    Abstract [en]

    The early Miocene was a period of major palaeogeographic reorganization in the eastern Mediterranean region, during which time the Anatolian Plateau became subaerial and several intracontinental basins intermittently became connected to the Paratethys and Mediterranean seas. In this paper, we analyse early Miocene vegetation and climate using leaf records, palynological assemblages, and fossil wood at 36 localities from western and central Turkey, most of which have precise age control based on radiometric dating and mammal faunal ages. Using the leaf flora of Güvem (Beş Konak, Keseköy), Climate Leaf-Analysis Multivariate Program (CLAMP) analyses and Köppen signatures were employed to infer a palaeoclimate typical of modern laurel forest regions. Based on the palynological records, abundance of various pollen-taxa was used as a measure of openness of vegetation and regional presence of major tree taxa. Most pollen floras are dominated by tree pollen (ranging from 85 to 98%) and indicated widespread afforestation. In the pollen diagrams, shifts in dominance from swamp forest elements (Taxodioideae) to well-drained forests (Pinaceae) indicate changes in lake levels or phases of basin development. Such shifts may have been associated with the development of more xeric forest vegetation. Wood anatomical features such as false tree rings further may indicate seasonal climate. Pollen diagrams and macrofossils reflect zonal and azonal broadleaf and needleleaf forest and extrazonal open vegetation. The latter occurred in areas with shallow soils on volcanic rocks or limestone (e.g. cycads, Dracaena), or coastal areas (herb dominance). Taxonomic composition and biogeographic affinities suggest laurel forest as a major forest biome on well-drained soils and ecotones between laurel forest and broadleaf deciduous forest biomes. A comparison with younger floras shows that these are neither more diverse nor more warmth-loving despite an increase in global temperature (Mid-Miocene Climatic Optimum) suggesting bottlenecks during previous (Oligocene) cooler times for warmth-loving taxa.

  • Ahmed, Mohammed
    et al.
    Swedish Museum of Natural History, Department of Zoology. Harper Adams University.
    Back, Matthew
    Prior, Thomas
    Karssen, Gerrit
    Lawson, Rebecca
    Adams, Ian
    Sapp, Melanie
    Metabarcoding of soil nematodes: the importance of taxonomiccoverage and availability of reference sequences in choosingsuitable marker(s)2019In: Metabarcoding and Metagenomics, Vol. 3, p. 77-99Article in journal (Refereed)
  • Rubinstein, Claudia
    et al.
    Department of Paleopalynology, IANIGLA, CCT CONICET Mendoza.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    Baltica cradle of early land plants? Oldest record of trilete spores and diversecryptospore assemblages; evidence from Ordovician successions of Sweden2019In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 141, p. 181-190Article in journal (Refereed)
    Abstract [en]

    The origin of land plants is one of the most important evolutionary events in Earth’s history. The mode and timing of the terrestrialization of plants remains debated and previous data indicate Gondwana to be the center of land-plant radiation at ~ 470–460 Ma. Here we present the oldest occurrences of trilete spores, probably the earliest traces of vascular land plants yet recorded. The spores occur in Ordovician, Sandbian (455 million years old) successions in central Sweden, once part of the paleocontinent Baltica. These strata are independently dated by marine microfossils (conodonts) and 206Pb/238U dating of volcanic ash deposits. Our discovery extends the record of trilete spores globally by ~8 million years, and for Baltica by ~25 million years. Additionally, cryptospore assemblages are identified revealing a diverse and stable mid-Ordovician (Darriwilian: ~ 460 Ma) vegetation of free-sporing plants. The formation of regolith substrates on land as a consequence of permanent plant cover must in turn have affected the marine biota. We link these early land plant spore occurrences to the extensive, nutrient-rich volcanic ash deposits and propose Baltica as the possible original region of the radiation of early land plants.

  • Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Hagström, Jonas
    Swedish Museum of Natural History, Department of Paleobiology.
    Kaim, Andrzej
    HRYNIEWICZ, Krzysztof
    First shark record (Chondrichthyes, Elasmobranchii) from the Paleogene of Spitsbergen, Svalbard2019In: Polish Polar Research, ISSN 0138-0338, E-ISSN 2081-8262Article in journal (Refereed)
  • JADWISZCZAK, Piotr
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    First partial skeleton of Delphinornis larseni Wiman, 1905, a slender-footed penguin from the Eocene of Antarctic Peninsula2019In: Palaeontologia Electronica, ISSN 1935-3952, E-ISSN 1094-8074Article in journal (Refereed)
  • KIMURA, Yuri
    et al.
    TOMIDA, Yukimitsu
    KALTHOFF, Daniela
    Swedish Museum of Natural History, Department of Zoology.
    CASANOVAS-VILAR, Isaac
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    A new endemic genus of eomyid rodents from the early Miocene of Japan2019In: Acta Palaeontologica Polonica, ISSN 0567-7920, E-ISSN 1732-2421Article in journal (Refereed)
  • Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    NIEDZWIEDZKI, Grzegorz
    CRISPINI, Laura
    LÄUFER, Andreas
    BOMFLEUR, Benjamin
    First evidence of a tetrapod footprint from the Triassic of northern Victoria Land, Antarctica2019In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369Article in journal (Refereed)
  • Amano, Kazutaka
    et al.
    Miyajima, Yusuke
    Jenkins, Robert
    Kiel, Steffen
    Swedish Museum of Natural History, Department of Paleobiology.
    The Neogene biogeographic history of vesicomyid bivalves in Japan, with two new records of the family2019In: The Nautilus, ISSN 0028-1344, Vol. 133, no 2, p. 48-56Article in journal (Refereed)
  • Hryniewicz, Krzysztof
    et al.
    Amano, Kazutaka
    Bitner, Maria Aleksandra
    Institute of Paleobiology, Polish Academy of Sciences, ul. Twarda 51/55, 00-818 Warszawa, Poland.
    Hagström, Jonas
    Swedish Museum of Natural History, Department of Paleobiology.
    Kiel, Steffen
    Swedish Museum of Natural History, Department of Paleobiology.
    Klompmaker, Adiël A.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Robins, Cristina
    Kaim, Andrzej
    A late Paleocene fauna from shallow-water chemosynthesis-based ecosystems in Spitsbergen, Svalbard2019In: Acta Palaeontologica Polonica, ISSN 0567-7920, E-ISSN 1732-2421, Vol. 64, no 1, p. 101-141Article in journal (Refereed)
  • Kase, Tomoki
    et al.
    National Museum of Nature and Science, Tokyo.
    Isaji, Shinji
    Natural History Museum and Institute, Chiba.
    Aguilar, Yolanda
    Mines and Geosciences Bureau, Quezon City, Philippines.
    Kiel, Steffen
    Swedish Museum of Natural History, Department of Paleobiology.
    A large new Wareniconcha (Bivalvia: Vesicomyidae) from a Pliocene methane seep deposit in Leyte, Philippines2019In: The Nautilus, ISSN 0028-1344, Vol. 133, no 1, p. 26-30Article in journal (Refereed)
  • Kiel, Steffen
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Peckmann, Jörn
    Resource partitioning among brachiopods and bivalves at ancient hydrocarbon seeps: A hypothesis2019In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 14, no 9, article id e0221887Article in journal (Refereed)
  • Biagioni, Cristian
    et al.
    Università di Pisa, Italy.
    Bindi, Luca
    Università di Firenze, Italy.
    Mauro, Daniela
    Università di Pisa.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Crystal chemistry of sulfates from the Apuan Alps (Tuscany, Italy). V. Scordariite, K8(Fe3+0.67ο0.33)[Fe3+3O(SO4)6(H2O)3)]2(H2O)11 , a new metavoltine-related mineral2019In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, no 11, p. 1-14, article id 0702Article in journal (Refereed)
  • Wotte, Thomas
    et al.
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    Martin J., Whitehouse
    Kouchinsky, Artem
    Swedish Museum of Natural History, Department of Paleobiology.
    Isotopic evidence for temperate oceans during the Cambrian Explosion2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 6330Article in journal (Refereed)
    Abstract [en]

    The Cambrian Explosion was a key event in the evolution of life on Earth. This event took place at a time when sea surface temperatures have been proposed to reach about 60 °C. Such high temperatures are clearly above the upper thermal limit of 38 °C for modern marine invertebrates and preclude a major biological revolution. To address this dichotomy, we performed in situ δ18O analyses of Cambrian phosphatic brachiopods via secondary ion mass spectrometry (SIMS). The δ18Ophosphate data, which are considered to represent the most primary δ18Oseawater signature, were identified by evaluating the diagenetic alteration of the analyzed shells. Assuming ice-free conditions for the Cambrian ocean and no change in δ18Oseawater (-1.4‰ to -1‰; V-SMOW) through time, our temperatures vary between 35 °C ± 12 °C and 41 °C ± 12 °C. They are thus clearly above (1) recent subequatorial sea surface temperatures of 27 °C–35 °C and (2) the upper lethal limit of 38 °C of marine organisms. Our new data can therefore be used to infer a minimal depletion in early Cambrian δ18Oseawater relative to today of about -3‰. With this presumption, our most pristine δ18Ophosphate values translate into sea surface temperatures of about 30 °C indicating habitable temperatures for subequatorial oceans during the Cambrian Explosion.

  • Topper, Timothy, P.
    et al.
    Guo, Junfeng
    Clausen, Sébastien
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    Zhang, Zhifei
    A stem group echinoderm from the basal Cambrian of China and the origins of Ambulacraria2019In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, article id 1366Article in journal (Refereed)
    Abstract [en]

    Deuterostomes are a morphologically disparate clade, encompassing the chordates (including vertebrates), the hemichordates (the vermiform enteropneusts and the colonial tube-dwelling pterobranchs) and the echinoderms (including starfish). Although deuterostomes are considered monophyletic, the inter-relationships between the three clades remain highly contentious. Here we report, Yanjiahella biscarpa, a bilaterally symmetrical, solitary metazoan from the early Cambrian (Fortunian) of China with a characteristic echinoderm-like plated theca, a muscular stalk reminiscent of the hemichordates and a pair of feeding appendages. Our phylogenetic analysis indicates that Y. biscarpa is a stem-echinoderm and not only is this species the oldest and most basal echinoderm, but it also predates all known hemichordates, and is among the earliest deuterostomes. This taxon confirms that echinoderms acquired plating before pentaradial symmetry and that their history is rooted in bilateral forms. Yanjiahella biscarpa shares morphological similarities with both enteropneusts and echinoderms, indicating that the enteropneust body plan is ancestral within hemichordates.

  • Li, Luoyang
    et al.
    Zhang, Xingliang
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    Yun, Hao
    Li, Guoxiang
    Bing, Pan
    Shell microstructures of the helcionelloid mollusc Anabarella australis from the lower Cambrian (Series 2) Xinji Formation of North China2019In: Journal of Systematic Palaeontology, ISSN 1477-2019, E-ISSN 1478-0941, Vol. 17, p. 1699-1709Article in journal (Refereed)
    Abstract [en]

    Although various types of shell microstructures are documented from Cambrian molluscs, the precise organization and mineralogical composition of Terreneuvian molluscs are relatively unknown. Anabarella was one of the first helcionellid molluscs to appear in the Terreneuvian, with the genus surviving until the third epoch of the Cambrian. Here, shell microstructures of Anabarella australis have been studied based on new collections from the lower Cambrian (Series 2) Xinji Formation of the North China Block. Results show that A. australis has a laminar inner shell layer that consists of crossed foliated lamellar microstructure (CFL). Nacreous, crossed-lamellar and foliated aragonite microstructures previously documented in the older (Terreneuvian) species A. plana are here revised as preservational artefacts of the CFL layers. This complex skeletal organization of Anabarella suggests that mechanisms of molluscan biomineralization evolved very rapidly. Morphologically, specimens from the Chaijiawa section show a pattern of distinct ‘pseudo-dimorphism’ as external coatings are identical to Anabarella, while associated internal moulds are similar to the helcionelloid genus Planutenia. In contrast, internal moulds from the Shangzhangwan section show considerable morphological variation owing to preservational bias and show greater similarities to specimens from South Australia, Northeast Greenland and Germany. These observations demonstrate that the extensive morphological variation seen in the internal moulds of the cosmopolitan genus Anabarella are primarily preservational artefacts and are unlikely to represent the real intra- and interspecific variability of the animal. In these cases, Planutenia is here confirmed to be a subjective synonym of Anabarella.

  • Bing, Pan
    et al.
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    Sun, Haijing
    Li, Guoxiang
    Biostratigraphical and palaeogeographical implications of Early Cambrian hyoliths from the North China Platform2019In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 43, p. 351-380Article in journal (Refereed)
    Abstract [en]

    A succession of diverse hyolith assemblages comprising 10 genera and 14 species are reported from the lower Cambrian Shangwan and Sanjianfang sections of the Xinji Formation, and Xiaomeiyao section of the Houjiashan Formation, which crop out along the southern margin of the North China Platform. Most of the specimens are represented by both conchs and opercula. The identified orthothecids include Conotheca australiensis, Cupitheca holocyclata, C. costellata, Neogloborilus applanatus, N. spinatus, Tegminites hymenodes, Triplicatella disdoma, T. xinjia sp. nov. and Paratriplicatella shangwanensis gen. et sp. nov. The hyolithids comprise Protomicrocornus triplicensis gen. et sp. nov., Microcornus eximius, M. petilus, Parkula bounites and Parakorilithes mammillatus. Some anomalous taxa possess characteristics of both Hyolithida and Orthothecida, such as C. australiensis, Neogloborilus and P. triplicensis. Protomicrocornus may constitute a sister group of other hyolithids. The teeth of Parkula bounites and clavicles of Parakorilithes mammillatus are documented for the first time. The hyolith assemblages from North China are probably coeval, and can be correlated with the Cambrian upper Stage 3–lower Stage 4. Many taxa are also globally distributed and have significant potential for biostratigraphical correlations. In accordance, the hyoliths from North China reveal closest compositional similarities to faunas from eastern Gondwana, and especially South Australia. However, some taxa are shared with Laurentian assemblages suggesting cosmopolitanism, and possibly planktonic larval dispersal.

  • Betts, Marissa, J.
    et al.
    Claybourn, Thomas M.
    Brock, Glenn, A.
    Jago, James, B.
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    Paterson, John, R.
    Shelly fossils from the lower Cambrian White Point Conglomerate, Kangaroo Island, South Australia2019In: Acta Palaeontologica Polonica, ISSN 0567-7920, E-ISSN 1732-2421, Vol. 64, no 3, p. 489-522Article in journal (Refereed)
    Abstract [en]

    The lower Cambrian (Series 2) White Point Conglomerate (WPC) on Kangaroo Island, South Australia contains exoticclasts representing a diverse array of lithologies, including metamorphics, chert, sandstone, and abundant carbonates,notably archaeocyath-rich bioclastic limestone. Acetic acid digestion of the WPC bioclastic limestone clasts reveals adiverse shelly fauna. This assemblage includes abundant organophosphatic brachiopods such as Cordatia erinae Brockand Claybourn gen. et sp. nov., Curdus pararaensis, Eodicellomus elkaniformiis, Eohadrotreta sp. cf. E. zhenbaensis,Eoobolus sp., Kyrshabaktella davidii, and Schizopholis yorkensis. Additional shelly taxa include the solenopleurid trilobiteTrachoparia? sp., the tommotiids Dailyatia odyssei, Dailyatia decobruta Betts sp. nov., Kelanella sp., and Lapworthellafasciculata, spines of the bradoriid arthropod Mongolitubulus squamifer, and several problematica, such as Stoibostrombuscrenulatus and a variety of tubular forms. The upper age limit for the WPC is constrained by biostratigraphic data fromthe overlying Marsden Sandstone and Emu Bay Shale, which are no younger than the Pararaia janeae Trilobite Zone(Cambrian Series 2, Stage 4). The shelly fossil assemblage from the WPC limestone clasts indicates an upper Dailyatiaodyssei Zone (= Pararaia tatei to lower P. janeae trilobite zones), equivalent to the Atdabanian–early Botoman of theSiberian scheme. This contrasts with the previously suggested late Botoman age for the limestone clasts, based on the diversearchaeocyath assemblage. The minor age difference between the WPC and its fossiliferous limestone clasts suggestsrelatively rapid reworking of biohermal buildups during tectonically-active phases of deposition in the Stansbury Basin.

  • Christensen-Dalsgaard, Signe
    et al.
    Anker-Nilssen, Tycho
    Crawford, Rory
    Bond, Alexander
    Már Sigurðsson, Guðjón
    Glemarec, Gildas
    Snær Hansen, Erpur
    Kadin, Martina
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Kindt-Larsen, Lotte
    Mallory, Mark
    Ravn Merkel, Flemming
    Petersen, Aevar
    Provencher, Jennifer
    Bærum, Kim Magnus
    What’s the catch with lumpsuckers? A North Atlantic study of seabird bycatch in lumpsucker gillnet fisheries2019In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 240, article id 108278Article in journal (Refereed)
    Abstract [en]

    Worldwide, incidental bycatch in fisheries is a conservation threat to many seabird species. Although knowledge on bycatch of seabirds has increased in the last decade, most stems from longline fisheries and the impacts of coastal gillnet fisheries are poorly understood. Gillnet fishing for North Atlantic lumpsucker (Cyclopterus lumpus) is one such fishery. We collated and synthesized the available information on seabird bycatch in lumpsucker gillnet fisheries across the entire geographical range to estimate and infer the magnitude of their impact on the affected seabird populations. Most birds killed were diving ducks, cormorants and auks, and each year locally high numbers of seabirds were taken as bycatch. We found large differences in bycatch rates among countries. The estimated mean bycatch in Iceland was 2.43 birds/trip, while the estimates in Norway was 0.44 and 0.39 birds/trip, respectively. The large disparities between estimates might reflect large spatial differences in bycatch rates, but could partly also arise due to distinctions in data recorded by onboard inspectors (Iceland), self-administered registration (Norway) and direct observations by cameras (Denmark). We show that lumpsucker gillnet fisheries might pose a significant risk to some populations of diving seabirds. However, a distinct data deficiency on seabird bycatch in terms of spatio-temporal coverage and the age and origins of the birds killed, limited our abilities to fully assess the extent and population consequences of the bycatch. Our results highlight the need for a joint effort among countries to standardize monitoring methods to better document the impact of these fisheries on seabirds.