Swedish Museum of Natural History
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NEMOte BARCODing: Förbättrad miljöövervakning av Östersjöns bentiska ekosystem
No full textFörändringar av ekosystem och hot mot biologisk mångfald, samt de på denna mångfald vilande ekosystemtjänsterna, har skapat ett behov av mer robusta och kostnadseffektiva miljöövervakningsmetoder. Projektet NEMOte BARCODing har undersökt om de frilevande nematoderna kan hjälpa oss att fylla detta behov. Metastreckkodning (metabarcoding på engelska), en av de moderna DNA-metoderna, har möjliggjort att meiofauna-organismer som nematoder effektiv kan provtas. Nematoderna är en av de mest mångfaldshaltiga organismgrupperna i världen, och de har visat sig vara bra indikatorer på ekosystems hälsa och förändringar i miljön. I Östersjön, där traditionellt enbart större organismer, makrofauna, har använts, kan nematoderna tillföra värdefull information. Då antal makrofauna-arter i Östersjön är lågt har bedömningar av ekosystemhälsa baserat på makrofauna mindre upplösning än bedömningar baserat på de mer mångfaldiga och abundanta nematod-samhället. Det finns dock hinder för DNA-streckkodning ska för att övervaka nematoder i Östersjön: 1. Bristande täckning av nematod-arter i nuvarande referensdatabaser. 2. Bristande kunskap om streckkodningsmetoders förmåga att kvantifiera nematod-samhället och återspegla samhällskompositionen i miljöerna som provtas. Och 3. Bristen på verktyg för att bedöma ekosystemhälsa och ekologiska status från data över nematod-samhället. NEMOte BARCODing har bidragit till att överkomma dessa brister och därigenom till att möjliggöra miljöövervakning av Östersjöns nematoder. I Arbetspaktet 1 förbättrade NEMOte BARCODing existerande referensdatabaser genom att ladda upp referenssekvenser av 18S och 28S rRNA-markörgenerna för 110 av Östersjöns nematod-arter. I Arbetspaket 2 utvärderades sekvenseringsmetoders lämplighet för miljöövervakning. 18S-streckkodning med TAReuk primerparen fungerade bäst av de testade metoderna, gav en god bild av nematod-samhället, och rekommenderas därav för nematod-övervakning i Östersjön. I Arbetspaket 3 har NEMOte BARCODing utvecklat ett verktyg för statusklassning med nematod-data, Nematod-BQI (BQInem), med utgångspunkt i det BQI som används inom svensk miljöövervakning. Andra potentiella verktyg för nematod-övervakning utforskades även och en karta ritades för Nematod-BQI:s framtida utvecklingen, med potentiell inkludering av fler meiofauna-grupper som ett alternativ. Slutligen så förslogs ett pilotprogram för streckkodningsbaserad nematod-övervakning, med rekommenderade metoder, provtagningsupplägg och status klassningsverktyg (BQInem). De frilevande nematoderna kan säga oss mycket om ekosystemens hälsa och arbetet inom NEMOte BARCODing har förhoppningsvis bidragit till att denna information förmedlas
Termite activity in the mid-Cretaceous of Australia
No full textIn this paper we provide the oldest evidence of termites in Australia, based on an aggregation of several hundred morphologically distinctive faecal pellets preserved as opalized casts from the Griman Creek Formation (Albian-Cenomanian: c. 100 Ma) at Lightning Ridge, New South Wales, Australia. This trace fossil extends the record of isopterans in Australia around 40 to 50 million years earlier than previously identified termite wing impressions, and indicates that this group was an active component of the detritivorous community in eastern Gondwanan terrestrial ecosystems by the mid-Cretaceous. The distinctive prismatic faecal pellets with hexagonal cross-sections (referable to Microcarpolithes hexagonalis Vangerow) were probably produced by kalotermitid or mastotermitid termites. The associated fossil plant assemblage indicates that the producers of the faecal pellets likely fed on conifer wood. Based on the distribution of extant termites, the climate of the Lightning Ridge area (Surat Basin) was probably warm and moist during the mid-Cretaceous. Recognition that termites were well established in Australian terrestrial ecosystems by the Albian-Cenomanian implies that vicariance may have been just as influential as trans-oceanic dispersal in determining the early distribution of major termite clades. Opalization of these delicate faecal pellets highlights the potential for further discoveries of three-dimensionally preserved soft or friable body and trace fossils in the Lightning Ridge opal deposits
Stratigrafiska enhetsnamn på svenska : Names of stratigraphic units in Swedish
No full textUniform spelling and grammatical rules facilitate the reader’s understanding of written text and reduce the risk of misunderstandings. The spelling of stratigraphic unit names has been discussed in the Swedish Committee for Geological Nomenclature (Svenska geologiska namnkommittén, SGNK) under the auspices of the Swedish National Committee for Geology (Svenska nationalkommittén för geologi, SNKG) and this has resulted in the following recommendations regarding the format of the initial letter (upper case or lower case) for various units.Enhetliga skrivregler underlättar läsarens förståelse av skriven text och minskar risken för missförstånd. Skrivsättet för stratigrafiska enhetsnamn har behandlats i Svenska geologiska namnkommittén (SGNK) inom Svenska nationalkommittén för geologi (SNKG) och resulterat i nedanstående rekommendationer avseende begynnelsebokstaven (versal eller gemen)
Refining Hf crust formation ages in Precambrian terranes
No full textThe mechanisms and timing of long term chemical differentiation of the Earth are fundamental questions in the geosciences. We present detrital zircon U-Pb, O and Hf isotope data from Fennoscandia to assess how crustal growth can be reconciled with its known >1.5 billion year geological history. A broadly linear evolution (176Lu/177Hf = 0.0403), from chondritic mantle at the age of the oldest identified Fennoscandian crust, to present day MORB values (εHf(0 Ma) ≈ fl16), provides a good fit with the most radiogenic zircon and whole rock Hf isotope data from the region. This mantle reference gives crustal growth peaks that correlate with known regional orogenic events. In contrast, a conventional 4.5 Ga strongly depleted mantle generates growth peaks outside of known geologic activity. Applying the same approach to the East Pilbara Terrane and SW Greenland yields model age peaks that also align with known magmatic activity. We propose that more geologically relevant crust formation ages are obtained via referencing a mantle source defined by the most radiogenic zircons/samples in the studied region
Phylogenomic analysis of Stylops reveals the evolutionary history of a Holarctic Strepsiptera radiation parasitizing wild bees.
No full textHolarctic Stylops is the largest genus of the enigmatic insect order Strepsiptera, twisted winged parasites. Members of Stylops are obligate endoparasites of Andrena mining bees and exhibit extreme sexual dimorphism typical of Strepsiptera. So far, molecular studies on Stylops have focused on questions on species delimitation. Here, we utilize the power of whole genome sequencing to infer the phylogeny of this morphologically challenging genus from thousands of loci. We use a species tree method, concatenated maximum likelihood analysis and Bayesian analysis with a relaxed clock model to reconstruct the phylogeny of 46 Stylops species, estimate divergence times, evaluate topological consistency across methods and infer the root position. Furthermore, the biogeographical history and coevolutionary patterns with host species are assessed. All methods recovered a well resolved topology with close to all nodes maximally supported and only a handful of minor topological variations. Based on the result, we find that included species can be divided into 12 species groups, seven of them including only Palaearctic species, three Nearctic and two were geographically mixed. We find a strongly supported root position between a clade formed by the spreta, thwaitesi and gwynanae species groups and the remaining species and that the sister group of Stylops is Eurystylops or Eurystylops + Kinzelbachus. Our results indicate that Stylops originated in the Western Palaearctic or Western Palaearctic and Nearctic in the early Neogene or late Paleogene, with four independent dispersal events to the Nearctic. Cophylogenetic analyses indicate that the diversification of Stylops has been shaped by both significant coevolution with the mining bee hosts and host-shifting. The well resolved and strongly supported phylogeny will provide a valuable phylogenetic basis for further studies into the fascinating world of Strepsipterans
Hur lär vi känna världens insekter?
No full textKunskapen om världens insekter ökar snabbt tack vare DNA- baserade metoder. Forskare vid Sveriges lantbruksuniversitet samt Naturhistoriska riksmuseet har tagit fram ett undervisningspaket för biologilärare som vill visa eleverna hur forskningen om insekter kan gå till, från sortering och laboratorietekniker till DNA-streckkodning
Editorial to the Special Collection “Controls and Biasing Factors in Sediment Generation, Routing, and Provenance: Models, Methods, and Case Studies”
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The European Reference Genome Atlas: piloting a decentralised approach to equitable biodiversity genomics
No full textA genomic database of all Earth’s eukaryotic species could contribute to many scientific discoveries; however, only a tiny fraction of species have genomic information available. In 2018, scientists across the world united under the Earth BioGenome Project (EBP), aiming to produce a database of high-quality reference genomes containing all ~1.5 million recognized eukaryotic species. As the European node of the EBP, the European Reference Genome Atlas (ERGA) sought to implement a new decentralised, equitable and inclusive model for producing reference genomes. For this, ERGA launched a Pilot Project establishing the first distributed reference genome production infrastructure and testing it on 98 eukaryotic species from 33 European countries. Here we outline the infrastructure and explore its effectiveness for scaling high-quality reference genome production, whilst considering equity and inclusion. The outcomes and lessons learned provide a solid foundation for ERGA while offering key learnings to other transnational, national genomic resource projects and the EBP
Floral and faunal biostratigraphy of the Middle–Upper Triassic Karamay and Huangshanjie formations from the southern Junggar Basin, China
No full textIn the Junggar Basin, northwestern China, the biostratigraphy and vegetation patterns of the MiddIe-Late Triassic sediments are comparativeIy poorly resolved. Here we investigate Middle-Late Triassic successions of the Dalongkou Section in the southern Junggar Basin for palynostratigraphy and vegetation patterns. Three palynological abundance zones are proposed here: the Aratrisporites Abundance Zone (Middle Triassic), the Dictyophyllidites-Aratrisporites Abundance Zone (latest Middle to early Late Triassic) and the Lycopodiacidites-Stereisporites informal abundance zone (Late Triassic). A review of previous records of the Fukangichthys Fauna indicates that this vertebrate fossil assemblage is stratigraphically located within the uppermost part of the Karamay Forrnation and is Middle Triassic in age. The revised dating of this and other faunas are further used to constrain the palynological zones in the Junggar Basin. Although the palynoftora is consistently dominated by non-striate bisaccate pollen (produced by seed fems and/ or conifers) in the studied section, spores record a distinctive abundance inerease during the late Middle Triassic. Spore taxon abundance changes indicate a vegetational shift from a Middle Triassic-early Late Triassic community characterized by abundant lycophytes (likely Annalepis and Pleuromeia) to a Late Triassic ecosystem with abundant dipteridaceous ferns (e.g. Dictyophyllum) in the Junggar Basin and across North China. This study updates the Triassic biostratigraphy in the Junggar Basin, and sheds light on temporal floral changes in this basin and elsewhere in North China during the Middle to Late Triassic.Also funded by the National Natural Sciences Foundation of China (NSFC 42002003).</p