Kiss P., Hudáčková N., Ruman A. & Heřmanová Z., 2018: An ontogenetic description of Orbulina suturalis (Foraminifera) from the Danube Basin (Slovakia). Acta Geologica Slovaca, 10, 1, 21–25.

An ontogenetic description of Orbulina suturalis (Foraminifera) from the Danube Basin (Slovakia)

Peter Kiss¹, Natália Hudáčková¹, Andrej Ruman¹ & Zuzana Heřmanová^2,3

¹Department of Mineralogy and Petrology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, SK-842 15 Bratislava, Slovakia; malickova3@uniba.sk
²Earth Science Institute of the Slovak Academy of Science, Dúbravska cesta 9, SK-840 05 Bratislava, Slovakia
³Earth Science Institute of the Slovak Academy of Science, Ďumbierska 1, SK-974 01 Banská Bystrica, Slovakia
⁴Department of Geological Sciences, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech Republic
⁵Gemological Institute, Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, Nábrežie mládeže 91, SK-949 74 Nitra, Slovakia

Abstract

Orbulina suturalis (Brönnimann, 1951) is a planktic foraminifera species that occurred in the Central Paratethys during the Middle Miocene, throughout the Badenian (Langhian, Serravallian) stage. Despite the stratigraphic and paleoecologic significance, the ontogeny of the species remained seldom explored. In this study the inner shell morphology was observed by using a tomographic microscope to identify the ontogenetic stages. The entire shell development of Orbulina suturalis, from the monothalamous prolocular stage to the polythalamous terminal stage, was interpreted. Each stage is described by its general morphological features, such as the dimensions of the shell, the shape and number of the chambers, the position of the aperture, the peripheral outline, the texture of the wall and the coiling direction. The constructed ontogenetic model of Orbulina suturalis was correlated with the „five stage concept” of Trilobatus sacculifer introduced by Brummer et al. (1987).

Key words: Orbulina suturalis, tomographic microscope, Badenian, Western Carpathians

Manuscript received: 2017-10-12

Revised version accepted: 2018-02-15