Swedish Museum of Natural History
Not a member yet
1516 research outputs found
Sort by
Conjectures and refutations: Species diversity and phylogeny of Australoheros from coastal rivers of southern South America (Teleostei: Cichlidae)
No full textMorphological and genetic analyses of species of Australoheros focusing on those distributed in coastal rivers from the Rio de La Plata north to the Rio Buranhém, support recognition of 17 valid species in the genus. Eight species are represented in coastal rivers: A. acaroides, A. facetus, A. ipatinguensis, A. oblongus, A. ribeirae, and A. sanguineus are validated from earlier descriptions. Australoheros mboapari is a new species from the Rio Taquari in the Rio Jacuí drainage. Australoheros ricani is a new species from the upper Rio Jacuí. Specimens from the Rio Yaguarón and Rio Tacuary, affluents of Laguna Merín, and tributaries of the Rio Negro, tributary of the Rio Uruguay are assigned to A. minuano pending critical data on specimens from the type locality of A. minuano. Australoheros taura is ajunior synonym of A. acaroides. Australoheros autrani, A. saquarema, A. capixaba, A.macaensis, A. perdi, and A. muriae are junior synonyms of A. ipatinguensis. Heros autochthon, A. mattosi, A. macacuensis, A. montanus, A. tavaresi, A. paraibae, and A. barbosae,are junior synonyms of A. oblongus. Heros jenynsii is a junior synonym of A. facetus
Taphonomy of tubular fossils (algae) from the deposits of the Late Ediacaria of Ukraine
No full textThe collection of Ediacaran algal flora is stored in the Institute of Geological Sciences of the National Academy of Sciences of Ukraine. These fossils were collected by Andrii Martyshyn in southwestern Ukraine. Within the framework of the priority topic “Integration of large-scale geological data to solve fundamental and applied problems of Ukraine”, which is being carried out at the Institute, the collection was revised. New fossil specimens of giant tubularstructures were also added, which we recently discovered in sediments (argillites, siltstones, sandstones) of the Mohyliv-Podilska series of the Ediacaran (Dniester river valley, southwestern Ukraine). The material is represented by three taphonomic variants of these remains: three-dimensionally preserved rods, phytoleimes and rods with charred shell fragments. We have collected a large number of fossils of soft-bodied organisms, trace fossils, macroalgae and problematic remains. Analysis of our findings suggests that some known and new fossils are likely to be the remains of algae. This interpretation is based on findings that demonstrate the different taphonomic states of preservation. The material of the new species of the previously described genus Harlaniella Sokolov in argillitic strata of the Kanylivka Group was described as traces of movement of worm-like creatures. These fossils look like straight or curved rods with oblique hatching on the lower surface of the rock. There are no trace fossils with similar morphology in the fossil record of the Phanerozoic. Our new material shows that the fossils were organic tubes with a smooth surface and an obliquely transverse sculpture on the inner surface of the wall. We found specimens with examples of the transition from smooth tubes into hatched rods and carbonaceous compression fossils (phytoleims). Similar phytoleims are widespread in this stratum and are described as remnants of probable brown algae Vendotaenia Gnilovskaja. New finds demonstrate a morphology different from the holotype: numerous branching segments and elasticity of deformed tubes. We did not detect holdfasts attaching bodies to the substrate, indicating a probable planktonic habit for these putative algae
Historical development of the territory of southern Ukraine in the Early and Middle Mesozoic
No full textStatus and Trends of Polybrominated Diphenyl Ethers (PBDEs) in Biota and Sediment
No full textBiota sites have good geographical coverage, sediment sites are more limited. PBDEs in sediment and biota have been stable (54% of assessed areas) or declining (46%) for the past 20 years. Concentrations are below thresholds (FEQGs) for all assessment areas and congeners, except BDE209 in Irish Sea sediment, and should not cause adverse effects to marine wildlife
The aberrant hamster Melissiodon (Cricetidae, Rodentia) from the early Miocene of Echzell and other German and French localities
No full textMelissiodon is a rare cricetid with a long stratigraphic range, present from the Oligocene until the Miocene, only found in western and central Europe except some specimens recovered in Anatolia. What makes Melissiodon special is its unique dental and mandible morphology that has led to many questions regarding its relationship to other cricetid genera and its type of diet. In this work, we have studied new material attributed to Melissiodon from the German localities Echzell (MN4) and Petersbuch (MN3 and MN4), and from the French locality Beaulieu (MN3). Moreover, we compared these specimens with the already published material from other localities across western and central Europe during the early Miocene (MN3 and MN4). In conclusion, the studied specimens and the comparison with other material from different European localities allow us to ascribe this new material as Melissiodon dominans, a widely dispersed species across Europe during the early Miocene.This publication is part of project I+D+i PID2020-117289GBI00 funded by MCIN/AEI/10.13039/501100011033/. It is also funded by the NSP (National Scholarship program of Slovak Republic for the Support of Mobility of University Researchers, ID 33758) to S.J.V. and by the Bolin Center for Climate Research, Stockholm University (RA6 grant) to T.M.</p
Mineralogy, geochemistry and microbiology insights into precipitation of stibnite and orpiment at the Daiyon-Yonaguni Knoll (Okinawa Trough) hydrothermal barite deposits
No full textSamples of active chimneys, chimney flanges and massive sulfides from the Daiyon-Yonaguni Knoll hydrothermal field are composed of major barite and minor stibnite and orpiment. Barite is inferred to precipitate from focused-discharge fluids composed of >40% hydrothermal end-member fluid at T = 100-240°C, whereas the stibnite and orpiment are later and lower temperature precipitates. The hydrothermal fluids from this field were subject of sub-seafloor boiling and phase separation and, consequently, are brine-rich depleted in volatile and enriched in non-volatile elements. Boiling and phase separation exerted major control on the rare earth elements (REE) partitioning in the vent fluids: high-chlorinity high-temperature fluids were enriched in light REE and low-chlorinity low-temperature fluids were enriched in heavy REE. Y/Ho molar ratio and Ce anomaly of the vent fluids suggest that the seawater has not completely reacted with the basement rocks and has not equilibrated with them. The trace element concentrations in the hydrothermal deposits suggest a complex interplay among hydrothermal, hydrogenetic and microbial processes. Sulfur isotope composition of the sulfides suggests that the sulfide S is a mixture of both basement rock and seawater S with a higher proportion of the basement rock S. The sulfate dissolved in the fluids was subjected to reduction during a slow mixing of hydrothermal fluid and seawater within the chimney walls of the Tiger and Abyss vents and this resulted in a heavy S-isotope composition of the vent fluid sulfate. Lead isotope composition of the hydrothermal deposits indicates mixing relationships suggesting that Pb and potentially other metals with similar geochemical behavior were derived from two or three sources. The Pb isotopes in the hydrothermal deposits imply that an enriched source, either sediments or extended continental lithosphere, and a depleted source, potentially back-arc mafic volcanics, are present in the area of Daiyon-Yonaguni Knoll. Filamentous orpiment found in the deposits is supposed to be either heavily mineralized fungal hyphae or pure abiogenic biomorphs. Presence of carbonaceous matter on and around the orpiment filaments suggests for microbial activity during filament formation. The filaments experienced temperature of 209.1±37.1°C which falls within the temperature range of the Daiyon-Yonaguni Knoll vent fluids. Stability phase diagrams modeling reveals that the stability of stibnite does not depend on the vent fluid chlorinity, but depends on the vent fluid temperature: the area of stibnite stability increases with decreasing vent fluid temperature and results in stibnite precipitation at low log10a of Sb2S42- and less reduced environment (Eh still <0). Orpiment is stable in a wide range of log10a of H2AsO4-, in reduced conditions and at high S activity. Barite is stable in wide range of log10a of Ba2+ and precipitates in slightly reduced to slightly oxic conditions
New discovery of rare insect damage in the Pliocene of India reinforces the biogeographic history of Eurasian ecosystems
No full textPlant–insect interactions in the fossil record are, as yet, sparsely known and understudied. Here, we document evidence of a new type of insect skeletonization on Abroma augustum (L.) L. f. (Malvaceae) leaf remains fromthe latest Neogene (Pliocene) sediments of Chotanagpur plateau, Jharkhand, eastern India. This unique skeletonization feeding trace attributable to herbivorous insects occurs all over the surfaces of our recovered Pliocene leaf remains. In the skeletonized area, the interveinal tissues are completely removed leaving behind only the tough leaf veins. This type of insect feeding behaviour is documented for the first time on Indian Cenozoic leaf remains. Based on published data, as well as our survey of modern forests adjacent to the fossil locality, we suggest that probable damage inducers of this skeletonization on Abroma Jacq. fossil leaves might be Chrysomelid (Coleopteran) beetles. This finding also reveals that specific insect feeding damage, such as the one presented here, can reveal similarity of environments despite the difference of plant species observed. Such results strengthen the importance of using plant–insect interactions on leaves as a complementary proxy to others revealing paleoenvironmental conditions
Utilizing museomics to trace the complex history and species boundaries in an avian-study system of conservation concern
No full textA taxonomic classification that accurately captures evolutionary history is essential for conservation. Genomics provides powerful tools for delimiting species and understanding their evolutionary relationships. This allows for a more accurate and detailed view on conservation status compared with other, traditionally used, methods. However, from a practical and ethical perspective, gathering sufficient samples for endangered taxa may be difficult. Here, we use museum specimens to trace the evolutionary history and species boundaries in an Asian oriole clade. The endangered silver oriole has long been recognized as a distinct species based on its unique coloration, but a recent study suggested that it might be nested within the maroon oriole-species complex. To evaluate species designation, population connectivity, and the corresponding conservation implications, we assembled a de novo genome and used whole-genome resequencing of historical specimens. Our results show that the silver orioles form a monophyletic lineage within the maroon oriole complex and that maroon and silver forms continued to interbreed after initial divergence, but do not show signs of recent gene flow. Using a genome scan, we identified genes that may form the basis for color divergence and act as reproductive barriers. Taken together, our results confirm the species status of the silver oriole and highlight that taxonomic revision of the maroon forms is urgently needed. Our study demonstrates how genomics and Natural History Collections (NHC) can be utilized to shed light on the taxonomy and evolutionary history of natural populations and how such insights can directly benefit conservation practitioners when assessing wild populations
New information on Trichophiala devylderi Aurivillius, 1879. Full description of both sexes, genetic study and lectotype designation (Lepidoptera, Eupterotidae)
No full textDescribed from Namibia, Trichophiala devylderi Aurivillius, 1879 is a species for which, apart from the original description of female “types”, little is known. Building upon recent observations in the field, investigations in variousmuseums that preserve specimens, and a review of the literature, we describe for the first time the habitat, the knowndistribution, the morphology of both sexes including the presence of two phenotypes, and the genitalia of both male andfemale. We also provide genetic information from several specimens that reveal little variation in the standard animalDNA barcode. Finally, we designate a lectotype among the three specimens preserved at the Naturhistoriska Riksmuseet,Stockholm, Swede