Rhynchonelliform brachiopods and trilobites of the ‘upper dark interval’ in the koněprusy area (Devonian, Eifelian, Kačák Event; the Czech Republic)

Abstract

Abstract The dark pelbiodetrital limestone beds of the ‘upper dark interval’ in the Koněprusy area, Central Bohemia, the Czech Republic, the assumed manifestation of the Kačák Event in this area, yielded a moderately diverse faunule of rhynchonelliform brachiopods and trilobites. In total, 15 species have been recognized (13 brachiopods and 2 trilobites), but the majority of them are only tentatively determined to generic level due to fragmentation, rarity or poor preservation. Brachiopod genera Leptaenopyxis, Protodouvillina, Douvillinella, Holynetes, Poloniproductus, Iridistrophia, Mystrophora, Pentamerella, Quasidavidsonia, Carinatina, Mimatrypa, Leptathyris, Eoreticularia and a single trilobite Astycoryphe were determined. The mode of preservation indicates transport of skeletal bioclasts from shallower parts of the basin and their fragmentation in debris flows together with fragments of terrestrial plants, crinoid detritus and numerous pelagic fossils, especially the dacryoconarid Nowakia ex gr. otomari. Associated conodonts (as well as trilobites) indicate a late Eifelian age for the fauna (Polygnathus ensensis Zone).