Foraminiferal Faunal Changes in the Upper Pliensbachian–Toarcian Ammonitico Rosso Sections (Bakonycsernye, Hungary)

Abstract

From the upper Pliensbachian–Toarcian interval of the Neotethys, this is the first record of isolated foraminiferal assemblages obtained from the Ammonitico Rosso limestone successions. The studied sections of Bakonycsernye (Hungary) had been dated by ammonites. The foraminiferal fauna extracted by glacial acetic acid yielded 86 benthic foraminiferal taxa. Most specimens belonged to the suborders Spirillinina and Lagenina followed by the Ammodiscina. The representatives of suborders Astrorhizina, Komokioidea, Verneuilinina, Robertinina, and Rotaliina were subordinated; miliolids were absent. Paralingulina csernyensis n. sp. was described from the upper Pliensbachian. The majority of species have wide stratigraphic ranges, however the previously known distributions of seven species changed based on their appearances in these sections. Nevertheless, the stratigraphic distributions of the foraminiferal species enabled accurate dating to stage-level. Based on the comparison of the taxonomic composition with other coeval foraminiferal faunas of the Neotethys, foraminiferal biozones and bioevents are discussed in this paper.