Lingulate brachiopods across the Kačák Event and Eifelian-Givetian boundary in the Barrandian area, Czech Republic

 

Authors: Mergl M

Published in: Bulletin of Geosciences, volume 94, issue 2; pages: 169 - 186; Received 1 January 2019; Accepted in revised form 4 April 2019; Online 10 May 2019

Keywords: Lingulata, Discinoidea, Siphonotretida, Eifelian, Kačák Event, taxonomy, Koněprusy, Barrandian,

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Abstract

Dark limestone interval of the late Eifelian (Polygnathus ensensis Zone) from the Koněprusy area in the Czech Republic yielded rare but remarkable organophosphatic brachiopod fauna, with the last-appearance datum of genera Paterula Barrande, 1879 and Orbaspina Valentine & Brock, 2003 in the fossils records. The first-appearance datum of the genus Lingulipora Girty, 1898 (represented by the L. budili sp. nov.) has been observed in the late Eifelian (Tortodus kockelianus Zone) yet below the dark limestone interval. New microbrachiopod Opsiconidion nanus sp. nov. and striking unnamed biernatiid are described from the upper Acanthopyge Limestone. Organophosphatic brachiopods confirm dramatic environmental changes at the latest Eifelian in the Barrandian. Demonstration of the Kačák Event (Polygnathus ensensis Zone) led to expansion of oxygen reduced environment over preceding shallow-water carbonate elevation. The expansion draws out the deep water and hypoxic (Orbaspina, Paterula) and likely epiplanktonic (Opatrilkiella Mergl, 2001a, Opsiconidion Ludvigsen, 1974) brachiopods over formerly much shallower environment. The Kačák anoxic Event likely triggered the Givetian to Famennian expansion of Lingulipora over the shelves of Laurussia palaeocontinent.