Brachiopod distribution through the Jurassic–Cretaceous transition in the western Tethyan pelagic realm: example from the Bakony Mountains, Hungary

Brachiopods, together with ammonoids, were collected bed-by-bed from several sections in the Bakony Mountains. The sections, straddling the Jurassic–Cretaceous transition, yielded abundant and diverse brachiopod material (1277 specimens, 18 species), and this offered a possibility to determine the stratigraphic ranges of the brachiopod species. The dating of the sections by ammonoids was supported by micropalaeontological (calpionellid and nannofossil) investigations. Three sections straddling the Jurassic–Cretaceous transition with continuous record with good ammonoid biostratigraphic zonation are documented in detail. It is demonstrated that, according to the stratigraphical distribution recorded in the Bakony sections, the most abundant brachiopod species range continuously from the Tithonian to the Berriasian, i.e. no change or turnover appears at the Jurassic/Cretaceous boundary. Our results endorse those published from the Pieniny Klippen Belt of Poland and underscore that, at least in the intra-Tethyan realm, the brachiopod species invariably crossed the Tithonian/Berriasian boundary.