Swedish Museum of Natural History
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A comprehensive 1:250,000 scale geological map of the Convoy Range and Franklin Island quadrangles (Victoria Land, Antarctica)
No full textA comprehensive geological map of the Convoy Range - Franklin Island USGS quadrangles (Victoria Land, Antarctica) integrates previous geological maps with new field data collected during the 2017/18 and 2018/19 austral summers by the XXXIII and XXXIV ItaliAntartide expeditions. This new geological map allows a complete coverage of Victoria Land, by filling the gap between the GIGAMAP program (a German / Italian agreement of cooperation to produce new geological maps of Victoria Land), to the north, and the maps by the New Zealand Antarctic program, to the south. The Lower Paleozoic basement is overlain by flat-lying Devonian to lower Jurassic cover of sedimentary and igneous rocks. The mapping highlighted some key features of this region, such as the scarce occurrence of rocks of the Wilson Metamorphic Complex, the occurrence of mafic rocks belonging to the Granite Harbour Intrusive Complex and the possible activity of faulting with hundreds of meter of vertical offset, linked to the post-Ross Orogeny tectonics. This new map can be used as the starting point for any future geological investigation in this region.This work benefited from the logistical and financial support of the Italian Programma Nazionale di Ricerche in Antartide (grant number PNRA16_00042, responsible G. Capponi)</p
Species-specific dynamics may cause deviations from general biogeographical predictions – evidence from a population genomics study of a New Guinean endemic passerine bird family (Melampittidae)
No full textThe family Melampittidae is endemic to New Guinea and consists of two monotypic genera: Melampitta lugubris (Lesser Melampitta) and Megalampitta gigantea (Greater Melampitta). Both Melampitta species have scattered and disconnected distributions across New Guinea in the central mountain range and in some of the outlying ranges. While M. lugubris is common and found in most montane regions of the island, M. gigantaea is elusive and known from only six localities in isolated pockets on New Guinea with very specific habitats of limestone and sinkholes. In this project, we apply museomics to determine the population structure and demographic history of these two species. We re-sequenced the genomes of all seven known M. gigantaea samples housed in museum collections as well as 24 M. lugubris samples from across its distribution. By comparing population structure between the two species, we investigate to what extent habitat dependence, such as in M. gigantaea, may affect population connectivity. Phylogenetic and population genomic analyses, as well as acoustic variation revealed that M. gigantaea consists of a single population in contrast to M. lugubris that shows much stronger population structure across the island. We suggest a recent collapse of M. gigantaea into its fragmented habitats as an explanation to its unexpected low diversity and lack of population structure. The deep genetic divergences between the M. lugubris populations on the Vogelkop region, in the western central range and the eastern central range, respectively, suggests that these three populations should be elevated to full species level. This work sheds new light on the mechanisms that have shaped the intriguing distribution of the two species within this family and is a prime example of the importance of museum collections for genomic studies of poorly known and rare species
Dynamic collapse and regrowth of the Antarctic Ice Sheet in the Weddell Sea sector during the middle Miocene: A novel multi-proxy sedimentary provenance approach using in-situ 87Rb/87Sr dating of detrital K-feldspar
No full textThe Sunda Region in maritime Southeast Asia: A tropical window into past global carbon-climate feedbacks
No full textManual for collection, preparation and storage of bird eggs for the Swedish National Monitoring Program for Contaminants in Marine Biota
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An earliest Triassic riparian ecosystem from the Bulgo Sandstone (Sydney Basin), Australia: palynofloral evidence of a high-latitude terrestrial vertebrate habitat after the end-Permian mass extinction
No full textA landmark change in terrestrial ecosystems took place after the end-Permian mass extinction (EPME). This was marked by disappearance of the iconic latest Permian Glossopteris forests in Australian continental successions dated to 252.10 ± 0.06 Ma (mega-annum). Pioneering earliest Triassic spore-producing plants then spread following catastrophic wildfires, soil erosion and algal blooms. These ruderal plant communities were later replaced by vast Dicroidium ‘seedfern’ forests, which established under warm, seasonally dry conditions. By contrast, evidence of coeval vertebrate assemblages is scarce in Australia. The Bulgo Sandstone (Narrabeen Group) fossil biota in the Sydney Basin is, therefore, important as a rare example of associated plant and animal communities from the Early Triassic. The fossils include imprints and organic remains of lycopsid roots and attributed leaves (microphylls), Dicroidium and Lepidopteris foliage, and both erythrosuchid and smaller-bodied archosauromorphs, capitosaurians and other temnospondyls, actinopterygian fishes and sharks. Here, we undertake a palynofloral analysis of the vertebrate fossil-bearing bed within the Bulgo Sandstone to determine the assemblage age and palaeoenvironment. We identified a low-diversity miospore suite that is overwhelmingly dominated by lycopsids (42%), and especially quillworts (Iso€etales/Pleuromeiales) represented by Densoisporites and Aratrisporites. Bryophyte (moss), sphenopsid (horsetail) and ground fern spores are also present. Pollen (14%) comprises forms mainly associated with voltzialean conifers. The non-taeniate bisaccate Falcisporites (Alisporites) produced by Dicroidium is comparatively rare (3%). Based on this taxic composition, we correlate the vertebrate-bearing layer ofthe Bulgo Sandstone with the lower part of the Protohaploxypinus samoilovichii Oppel Zone and suggest a late Induan to early Olenekian age. Calculated sedimentation rates indicate that the 400 m of sediments between the top of the Vales Point Coal and the base of the Bulgo Sandstone were laid down within a time span of 40–400 ka (kilo-annum). Furthermore, the high portion of spores (37%) implies a parautochthonous organic accumulation that would have derived from local vegetation. This was likely riparian, with Dicroidium (and associated gymnosperm) cuticles (ca 20%) being over-represented because of a deciduous seasonal cycle. Notably, the Bulgo Sandstone accumulated on a high-palaeolatitude floodplain (ca 66–69�S) with dense vegetation flanking waterways that might have provided both shelter and forage for terrestrial vertebrates living less than 1 Ma after the EPME ecosystem collapse.VV was funded by The Knut and Alice Wallenberg Foundation [KAW 2020.0145] and the Swedish ResearchCouncil [VR 2019-4061]. BPK was supported by theSwedish Research Council [VR 2020-3423] and a Matariki Network of Universities fellowship from Uppsala University in collaboration with The University of Western Australia for sabbatical research in Australia. </p
Excavating the fossil record for evidence of leaf mining
No full textLeaf mining is a highly specialized endophytic feeding style that evolved independently, within multiple lineages, in four major insect orders: Coleoptera (beetles), Hymenoptera (wasps), Diptera (flies), and Lepidoptera (moths and butterflies). Mining is carried out by the larval stages of these groups with chewing mouthparts, and this feeding strategy confers benefits to the herbivore by protecting the egg, larva, and pupa from predators between the two cuticle layers of the leaf within the mesophyll where the animal has aready source of nutrition. However, the evolutionary trajectories of leaf-mining behavior are little understood. This is particularly thecase for the Jurassic (201.4–145 Ma), which is sometimes regarded as a ‘black hole’ in the fossil record of leaf mining.The authors are supported by a grant from the Swedish ResearchCouncil (VR grant no.: 2022-03920). The authors thank Dr LuisMiguel Sender (Dinopolis), Dr Patricia Velasco de Leon(UNAM),Dr AntonioHernandez (UPV), and Dr Letizia Janaina (MSZUSP)for providing access to fossils and photographs of selected mines.</p
