Biotic responses to the Late Devonian global events: Introductory remarks

The main aim of this thematic issue is to present new high-resolution taxonomic data and ecologic interpretations that are currently available for the Kellwasser Crisis and other Late Devonian events from different parts of the Devonian world. Nine contributions present results of studies of eastern Laurussian epeiric successions in the framework of the international project “Ecosystem Aspects of Late Devonian Biotic Crisis

FIRST REPORT ON THE UPPERMOST PERMIAN OSTRACODS FROM THE MASORE SECTION (EXTERNAL DINARIDES), SLOVENIA

The ostracod assemblages from the Upper Permian and Permian-Triassic transitional strata of the Masore section in the External Dinarides (Slovenia) were studied. Altogether 13 genera and 20 species of the orders Palaeocopida, Platycopida and Podocopida are identified and illustrated. All recovered ostracods belong to shallow marine taxa. The older fauna from the uppermost Permian and the younger fauna from the Permian-Triassic boundary strata are distinguished. The obtained fauna from the Permian Bellerophon Formation corresponds to the “benthonic ostracod Eifelian Mega-assemblage” occupying the shelf sea floors. This study presents the first report of ostracod faunas from the uppermost Permian and Permian-Triassic boundary interval of Slovenia. The recovered ostracod fauna display a distinct faunal change and yield important paleobiogeographic implications as it reveals similarity with stratigraphical equivalent faunas from some other neighboring localities in the western Paleotethys, such as Bulla in Italy, Komirić in Serbia, and the Bükk Mountains in Hungary

Recent ostracods in surface sediment samples from Admiralty Bay, King George Island, West Antarctica

Ostracods from Admiralty Bay on King George Island (South Shetland Islands) represent 29 podocopid species, belonging to 19 genera, one cladocopid and six myodocopid species. They were recovered from Recent marine and/or glacio-marine sediment samples from water depths of up to 520 m. These ostracods constitute a variable assemblage, which is overall typical for the Antarctic environment. Shallow-water assemblages tend to be more variable in terms of frequencies and species richness than deep-water assemblages. The later are low in numbers and remain relatively high diversities. Overall, no linear relation between ostracod assemblage-composition and environmental features analyzed was recognized

Depositional environment of the Owadów-Brzezinki conservation Lagerstätte (uppermost Jurassic, central Poland) : evidence from microfacies analysis, microfossils and geochemical proxies

The Owadów-Brzezinki quarry is one of the most important paleontological sites in Poland, known for its exceptionally well-preserved Upper Jurassic (Middle Volgian = uppermost Lower Tithonian) fossils. Carbonate deposits of the section record a transition from an offshore to coastal and lagoonal settings and have been studied based on microfacies, micropalaeontological, isotope and chemical proxies. The obtained data point to normal marine conditions during the deposition of the older part of the quarry section in an offshore setting and a gradual transition into lagoonal environment characterized by high-amplitude variations in seawater salinity and oxygenation level of bottom waters, both of which resulted in considerable changes in benthic fauna assemblages or in the total lack of the fauna at some intervals. Above-mentioned conditions during the deposition of the middle part of the quarry section have probably allowed the preservation of diversified fauna with soft tissues. The microfacies and chemical data indicate that dysoxic/anoxic episodes may have occurred not only during the deposition of known fauna-rich beds but also during the deposition of poorly studied, so far, younger part of the section. The uppermost part of the carbonates exposed in the Owadów-Brzezinki quarry originated during the re-appearance of normal marine chemistry mostly in the intertidal-subtidal settings. The depositional conditions of the Owadów-Brzezinki site are non- typical, among famous conservation Lagerstätten, owing to the rapid fluctuations in the oxygenation and salinity of bottom waters