11 research outputs found

    A new record of the enigmatic mollusc Jinonicella from the Silurian of the Carnic Alps, Austria

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    The small enigmatic mollusc Jinonicella kolebabai Pokorny, 1978 is described from the upper Silurian Cardiola Formation at the Rauchkofel Sud section of the Carnic Alps, Austria. The associated conodonts suggest a late Ludlow (Ludfordian) Polygnathoides siluricus conodont Zone. Previous Silurian records of Jinonicella are known from the Wenlock to Ludlow of the Czech Republic, USA, Gotland of Sweden and the Carnic Alps of Austria. The wide distribution of this taxon across different climatic zones and widely separated areas in the Silurian is problematic, and it is unclear whether Jinonicella was present in high-latitude areas before the end-Ordovician cooling and mass extinction or was dispersed during the Silurian. Possible planktotrophy in Jinonicella and Silurian ocean circulation patterns may explain the dispersal, but within the framework of current palaeogeographical reconstructions the model does not adequately explain an equatorial to polar distribution of other contemporaneous benthic faunas from these areas

    A pelagic myodocopid ostracod from the Silurian of Arctic Russia

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    The Silurian myodocope ostracod Richteria migrans is reported from Arctic Russia, from Kotel’ny Island (New Siberian Islands) and the Taimyr Peninsula in strata of Ludfordian (late Ludlow, Late Silurian) age. These occurrences extend the biogeographical range of R. migrans from tropical to mid latitudes of the Early Palaeozoic Rheic Ocean in the palaeo-Southern Hemisphere, into subtropical regions of the palaeo-Northern Hemisphere on, or adjacent to, the Siberia Palaeocontinent. The new records reinforce the idea that R. migrans had wide dispersal capacity and probably possessed a pelagic lifestyle. It also endorses the use of R. migrans as a biostratigraphical marker fossil for the Ludfordian Stage, Ludlow Series, Upper Silurian

    New records of brachiopods and crinoids from the Silurian (Wenlock) of the southern Urals, Russia

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    Crinoids and brachiopods are described from the Silurian Uzyan Formation of the Zilair Zone in the southern Urals. The occurrence of the graptolites Coronograptus praedeubeli suggests a late Homerian (Wenlock) age for the strata. A new disparid crinoid, Cicerocrinus gracilis Donovan sp. nov., is the oldest known member of this genus. It has a long, flexible and homeomorphic column, and a tall bryozoan palaeontology terminology (IBr2) (second primibrachial) axillary. All species of Cicerocrinus described previously have been limited to the Ludlow of the British Isles, Sweden and Estonia, and the Pridoli of Estonia. The poorly preserved brachiopod fauna is represented by small atrypid (Atrypa? sp.) and dalmanellid brachiopods (Levenea? sp.). The reported assemblage generally inhabited deep-water environments
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