| 1. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
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New onychochilid mollusks from the Middle and Upper Ordovician of Baltica and Laurentia
- 2021
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Ingår i: Journal of Paleontology. - : Cambridge University Press. - 0022-3360 .- 1937-2337. ; 95:1, s. 106-122
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Tidskriftsartikel (refereegranskat)abstract
- A new sinistrally coiled univalved mollusk Catalanispira n. gen. is described with two species; Catalanispira reinwaldti (Öpik, 1930) from the Middle Ordovician Kõgekallas Formation (Darriwilian) of Estonia and Catalanispira plattevillensis n. gen. n. sp. from the Upper Ordovician Platteville Formation (Sandbian) of northern Illinois, USA. Morphological features include a large, low-trochiform shell, a narrow lenticular aperture, a deep funnel-like umbilicus, a falcate inner lip and a large (1.4 mm wide) protoconch. Ornamentation consists of fine commarginal growth lines or ribs but superimposed on a slightly irregular shell surface. Catalanispira n. gen. is placed within the sinistrally coiled order Mimospirida and the family Onychochilidae, and Catalanispirinae n. subfam. is proposed. The large Lower Ordovician (Tremadocian) Pelecyogyra Ebbestad and Lefebvre, 2015 from Morocco and France is transferred to this new subfamily. The well-preserved initial growth stage of Catalanispira plattevillensis n. gen. n. sp. is cap-shaped, slightly asymmetrical, unusually large, and smooth, and represents either an unusually large embryonic shell (protoconch 1) or a larval shell (protoconch 2). It differs from the smaller protoconch described for the clisospirine Mimospira Koken in Koken and Perner, 1925, which might include a multiwhorled larval shell (protoconch 2). Mimospirids are dominantly Ordovician, and have been classified as untorted mollusks (only distantly related to gastropods), dextral hyperstrophic gastropods, or sinistral orthostrophic gastropods. Sinistral asymmetry already in the embryonic shell and lack of conclusive evidence for coiling direction, e.g., an operculum, could suggest that Catalanispira n. gen. or similar mimosprids were sinistral orthostrophic gastropods. Currently the group is therefore classified as a group of sinistral orthostrophic gastropods, unranked within the Gastropoda.
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| 2. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
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Otto Zdansky : The scientist who discovered Peking Man and explored China’s fossil past
- 2021
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- During his nearly three years in China, the Austrian-Swedish palaeontologist Otto Zdansky (1894–1988) made pioneering discoveries of fossil faunas that greatly enhanced the understanding of the evolution of Chinese vertebrates. The most important was found in 1921 during his very first field trip in the country, to Zhoukoudian outside Beijing, where he discovered a fossil human tooth of Peking Man (Homo erectus pekinensis). Zdansky had come to Sweden in 1920 as an exchange student at Uppsala University, before travelling to China to take part in the Sino-Swedish science collaborations run there by the geologist Johan Gunnar Andersson. At the time there was an ongoing scientific race to find conclusive evidence of early Man in Asia, and although Zdansky never made much out of it, his discovery of Peking Man became a world sensation. Soon Zdansky also excavated some of the first dinosaurs ever found in China and surveyed the so-called Hipparion fauna that today is of great importance for the understanding of ancient climate changes.This book celebrates the 100th anniversary of both the ground-breaking discovery of Peking Man and of Otto Zdansky’s arrival in China. It tells the story of Zdansky’s life, tracks his fieldwork in China, explains his scientific achievements and also presents for the first time his own memoirs illustrated with photos, drawings and documents from Swedish archives.
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| 3. |
- Streng, Michael, 1971-, et al.
(författare)
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First record of an Early Ordovician brachiopod and conodont fauna from Lapland, Sweden
- 2022
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Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 144:1, s. 24-40
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Tidskriftsartikel (refereegranskat)abstract
- An Early Ordovician fauna of linguliform brachiopods and euconodonts is described from the Alum Shale Formation in northernmost Vasterbotten County, northern Sweden. The fauna was recovered from a single carbonate concretion collected at an exposure near the northern shore of Lake Storvindeln. Despite of the fragmentary and tectonized preservation of the obtained fossils, at least eight different taxa of linguliform brachiopods and four species of euconodonts could be identified. Among the brachiopods, the ephippelasmatid Pomeraniotreta biernatae Bednarczyk, 1986 is most common; it is associated among others with the acrotretids Eurytreta cf. sabrinae (Callaway, 1877) and Ottenbyella sp., and a spinose specimen potentially representing the zhanatellid Thysanotos. Two of the brachiopod taxa appear to present new species, Pomeraniotreta n. sp. and Mytoella? n. sp., but additional material would be needed for a formal description. Euconodont specimens are rare and comprise coniform elements of Drepanodus arcuatus Pander, 1856, Drepanoistodus aff. amoenus (Lindstrom, 1955) sensu Lofgren (1994), Paroistodus numarcuatus (Lindstrom, 1955) and Rossodus aff. manitouensis Repetski & Ethington, 1983. Evaluation of the stratigraphic distribution of the different taxa of brachiopods and euconodonts under consideration of the local geology, suggests that the investigated sample represents a level in the upper part of the Tremadocian (Tr2) part of the Alum Shale Formation. The fauna represents the northernmost occurrence of age diagnostic Early Ordovician (Tremadocian) fossils in Sweden.
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| 4. |
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| 5. |
- Agic, Heda, et al.
(författare)
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Late Ediacaran occurrences of the organic-walled microfossils Granomarginata and flask-shaped Lagoenaforma collaris gen. et sp. nov.
- 2022
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Ingår i: Geological Magazine. - : Cambridge University Press. - 0016-7568 .- 1469-5081. ; 159:7, s. 1071-1092
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Tidskriftsartikel (refereegranskat)abstract
- New occurrences of flask-shaped and envelope-bearing microfossils, including the predominantly Cambrian taxon Granomarginata, are reported from new localities, as well as from earlier in time (Ediacaran) than previously known. The stratigraphic range of Granomarginata extends into the Cambrian System, where it had a cosmopolitan distribution. This newly reported Ediacaran record includes areas from Norway (Baltica), Newfoundland (Avalonia) and Namibia (adjacent to the Kalahari Craton), and puts the oldest global occurrence of Granomarginata in the Indreelva Member (< 563 Ma) of the Stahpogieddi Formation on the Digermulen Peninsula, Arctic Norway. Although Granomarginata is rare within the assemblage, these new occurrences together with previously reported occurrences from India and Poland, suggest a potentially widespread palaeogeographic distribution of Granomarginata through the middle-late Ediacaran interval. A new flask-shaped microfossil Lagoenaforma collaris gen. et sp. nov. is also reported in horizons containing Granomarginata from the Stahpogieddi Formation in Norway and the Dabis Formation in Namibia, and flask-shaped fossils are also found in the Gibbett Hill Formation in Newfoundland. The Granomarginata-Lagoenaforma association, in addition to a low-diversity organic-walled microfossil assemblage, occurs in the strata postdating the Shuram carbon isotope excursion, and may eventually be of use in terminal Ediacaran biostratigraphy. These older occurrences of Granomarginata add to a growing record of body fossil taxa spanning the Ediacaran-Cambrian boundary.
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| 6. |
- Agic, Heda, et al.
(författare)
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Life through an Ediacaran glaciation : Shale- and diamictite-hosted organic-walled microfossil assemblages from the late Neoproterozoic of the Tanafjorden area, northern Norway
- 2024
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier. - 0031-0182 .- 1872-616X. ; 635
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Tidskriftsartikel (refereegranskat)abstract
- New organic-walled microfossil (OWM) assemblages are reported from upper Neoproterozoic glacial and interglacial siliciclastic deposits in Finnmark, northern Norway. A nearly continuous sedimentary succession of the Vestertana Group contains two glaciogenic units, the Smalfjorden and Mortensnes formations, interpreted as end-Cryogenian Marinoan and Ediacaran glaciations, respectively. We investigated the OWM record in the Nyborg, Mortensnes, and St ' ahpogieddi formations to assess the impact of a glacial interval on the diversity of microscopic eukaryotes. A modified acid-extraction technique was applied to recover OWM from the diamictite matrix. The upper Nyborg Formation contains morphologically complex Doushantuo-Pertatataka acritarchs (DPA), restricting the age of the Nyborg Formation to early-mid Ediacaran. DPA occur below the dolostones that record a negative carbon isotope excursion correlated with the Shuram anomaly and below a glacial diamictite. A decline in species richness and compositional change is observed in the Mortensnes glacial assemblage. DPA are replaced by bacterial filaments and cell aggregates. The overlying Indreelva Member, St ' ahpogieddi Formation contains Ediacara-type biota and palaeopascichnids, but only a depauperate OWM assemblage of leiosphaerids and flask-shaped microfossils characteristic of the late Ediacaran.The succession of assemblages in the Vestertana Group demonstrates a turnover from large eukaryotic OWM to a microbial community in the glacial interval, to a low diversity post-glacial assemblage during the rise of macroscopic life. We compared the Vestertana record to global DPA occurrences. Although one DPA assemblage zone postdates the Shuram excursion, no DPA occur above Ediacaran glacial diamictites in successions where those deposits are present. Considering this, and the community changes in the Vestertana succession, we suggest that DPA were affected by the onset of an Ediacaran glaciation. Lastly, we combined the biostratigraphic markers in the Vestertana Group to constrain the age of the Mortensnes diamictite.
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| 7. |
- Agic, Heda, et al.
(författare)
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Life through the 'Varanger ice ages' : microfossil record of late Neoproterozoic glacial-interglacial units from arctic Norway
- 2018
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Ingår i: Geological Society of America <em>Abstracts with Programs</em>. - : Geological Society of America.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The late Neoproterozoic strata in Finnmark (Arctic Norway) provide a good sedimentary record of Neoproterozoic glaciations on the Baltica paleocontinent. The lower Vestertana Group exposed on the Digermulen Peninsula contains two glaciogenic units, the Smalfjord and Mortensnes formations. Chemostratigraphic correlation dated the Smalfjord diamictite to the Marinoan glaciation (650-635 Ma), yet its age was also proposed to be older, per correlation to glacial units in central and southern Scandinavia. The diamictites are bracketing shales and siltstones of the interglacial Nyborg Formation. Stratigraphic, paleontological, and sedimentological data are presented from the interglacial-glacial succession, investigated by the Digermulen Early Life Research Group. Palynological analysis yielded well-preserved organic-walled microfossils (OWM) from the Nyborg Fm., and from fine-grained diamictite matrix in the Mortensnes Fm. via a modified extraction method.The interglacial Nyborg Fm. hosts a moderate diversity assemblage of prokaryotic and eukaryotic OWM, as well as acanthomorphic acritarchs such as Ceratosphaeridium, ?Cavaspina, and a novel process-bearing form. Organically preserved, enigmatic multicellular eukaryotic fossils occur in the upper Nyborg Fm. The Mortensens glacial assemblage is less diverse and contains bacterial filaments, leiosphaerids, toroidal forms, and Micrhystridium-type minute acanthomorphs.The presence of Doushantuo-Pertatataka type acritarchs in the Nyborg Fm., and small acanthomorphs in the Mortensnes diamictite corroborate an early Ediacaran age for the interglacial-glacial succession on Digermulen. In addition to the trace fossil and body-fossil record of Ediacara-biota in the overlying Stáhpogieddi Formation, the microfossil biostratigraphy suggests Marinoan and Gaskiers glaciation equivalent ages of the Varanger glaciations in Finnmark. Protistan diversity in the succession declined through and following the glaciation, until late Ediacaran.
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| 8. |
- Agić, Heda, 1989-, et al.
(författare)
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Organically-preserved multicellular eukaryote from the early Ediacaran Nyborg Formation, Arctic Norway
- 2019
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Eukaryotic multicellularity originated in the Mesoproterozoic Era and evolved multiple times since, yet early multicellular fossils are scarce until the terminal Neoproterozoic and often restricted to cases of exceptional preservation. Here we describe unusual organically-preserved fossils from mudrocks, that provide support for the presence of organisms with differentiated cells (potentially an epithelial layer) in the late Neoproterozoic. Cyathinema digermulense gen. et sp. nov. from the Nyborg Formation, Vestertana Group, Digermulen Peninsula in Arctic Norway, is a new carbonaceous organ-taxon which consists of stacked tubes with cup-shaped ends. It represents parts of a larger organism (multicellular eukaryote or a colony), likely with greater preservation potential than its other elements. Arrangement of open-ended tubes invites comparison with cells of an epithelial layer present in a variety of eukaryotic clades. This tissue may have benefitted the organism in: avoiding overgrowth, limiting fouling, reproduction, or water filtration. C. digermulense shares characteristics with extant and fossil groups including red algae and their fossils, demosponge larvae and putative sponge fossils, colonial protists, and nematophytes. Regardless of its precise affinity, C. digermulense was a complex and likely benthic marine eukaryote exhibiting cellular differentiation, and a rare occurrence of early multicellularity outside of Konservat-Lagerstatten.
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| 9. |
- Agic, Heda, et al.
(författare)
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Unusual organic-walled microfossil from the late Neoproterozoic Nyborg Formation, Digermulen Peninsula, Arctic Norway
- 2017
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Ingår i: ISECT 2017.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The late Neoproterozoic Nyborg Formation is exposed in the Tanafjord area, Finnmark, Arctic Norway, on Digermulen and Varanger Peninsulas. The succession is composed of ~400 m of interbedded shales, siltstone and purple to grey sandstone, deposited between Neoproterozoic low latitude glacial deposits. The Nyborg Fm. lies on top of the Smalfjord diamictite, and is overlain by the Mortensnes diamictite (the latter was attributed to both Marinoan (650-635 Ma) and Gaskiers (579 Ma) glaciations) and the Ediacaran-Cambrian Stáhpogieddi Formation. Thus, the Nyborg Fm. represents late Neoproterozoic, probably the last Cryogenian interglacial interval. Presented material was collected in 2014 by members of Digermulen Early Life Research Group, from organic-rich, grey-green shales and siltstones of the Nyborg Mbr. D, uppermost Nyborg Fm. between Árasulluokta and Guvssájohka valleys. Organic-walled microfossils were extracted from shale via standard palynological acetolysis in hydrofluoric acid, and studied via light and scanning electron microscopy. Microfossils from the Nyborg Fm. include Synsphaeridium-type aggregated cells, unbranched bacterial filaments (Polythrichoides and Siphonophycus), sphaeromorph and envelope-bearing acritarchs (leiosphaerids, Stictosphaeridium, Simia), and previously unrecognized aggregated tubular microfossils. These taxa are long-ranging, but common in glacial-interglacial units worldwide, and thus broadly corroborate the Cryogenian age of the Nyborg sediments. The novel fossil, up to 300 μm in size, is a parenchymatous meshwork of interconnected organic-walled tubes that terminate in cup-shaped apices 4-11 µm in diameter. Irregular tube clusters are truncated both in macerates and in thin sections, suggesting post mortem transport. Elemental EDXS analysis indicates that extracted meshwork microfossils are predominantly composed of carbonaceous material and also associated with small amounts of titanium and vanadium. Considering the branching and adjoined body plan of carbonaceous fossil, it was likely multicellular and of eukaryotic affinity. As such, it may represent an important step in the evolution of complex multicellularity and morphological complexity several million years before the appearance of Ediacaran organisms.
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| 10. |
- Berg-Madsen, Vivianne, et al.
(författare)
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An orthothecid hyolith with a digestive tract from the early Cambrian of Bornholm, Denmark
- 2018
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Ingår i: GFF. - : TAYLOR & FRANCIS LTD. - 1103-5897 .- 2000-0863. ; 140:1, s. 25-37
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Tidskriftsartikel (refereegranskat)abstract
- The hyolith assemblage from the early Cambrian of Bornholm, Denmark, shows a higher diversity than contemporary assemblages in Baltoscandia. The most common species in the Green Shales (Laesa Formation, Norretorp Member, Cambrian Stage 3), is Hyolithes [=Hyolithus] (Orthotheca) johnstrupi Holm, 1893. A specimen of this species shows a well-preserved and almost complete digestive tract, folded into an approximately 22mm long chevron-like structure comprised of at least 20 arcuate loops on the ventral side and a flattened, gently sinuous to straight anal tube on the dorsal side. The thin, phosphatic outer shell layer of the conch is crushed under the digestive tract due to compaction while the digestive tract is preserved in three dimensions and appears undisturbed. The shape of the digestive tract is similar to that of the middle Cambrian Guduguwan hardmani (Etheridge) from Australia and the lower Cambrian specimens from Russia described by Mekova & Sysoev. The Danish specimen is probably an adult, lending support to the idea that the orthothecid digestive tract becomes more complex during ontogeny. Hyolithus (Orthotheca) johnstrupi is revised and here referred to Circotheca Sysoev, 1958.
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