International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

An updated generic status of Ammogloborotalia aff. subvesicularis (Hanzlíková) from the Middle Eocene deposits of the Fore-Magura Unit (Polish Outer Carpathians)

Published: Aug 2023

Pages: 347 - 353



Abstract: The Middle Eocene microfauna of the Fore-Magura Unit contains rich foraminiferal assemblages with numerous trochospiral, agglutinated species originally described as Trochammina subvesicularis Hanzlíková. The paper provides a reconsideration of this taxon due to its inconclusive generic status. A new insight into the systematics of trochamminid species is also discussed. A total of 25 samples from Middle Eocene slope marl deposits of the Fore-Magura Unit (from the western part of the Polish Outer Carpathians) were taken for examination. Based on the analysis of 183 specimens recovered from deep-sea mixed foraminiferal assemblages the species is assigned to the genus Ammogloborotalia (Zheng & Fu). The Eocene specimens, named under different generic names and in open nomenclature, similar to the description of Trochammina subvesicularis Hanzlíková, should be referred to the taxonomic name Ammogloborotalia aff. subvesicularis. Similar to modern species of Ammogloborotalia (Zheng & Fu), their Middle Eocene representatives imply a bathyal water depth and good connection of the flysch-type Fore-Magura zone basin with the World Ocean.

Keywords: agglutinated foraminifera, taxonomy, Eocene, Polish Outer Carpathians, Fore-Magura Unit

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