Fossilized-Brood Chambers in Nummulites vascus from Libya

Ahmed M. Muftah

doi:10.59743/jmset.v1i2.119

Authors

Ahmed M. Muftah Department of Earth Sciences, Faculty of Science, University of Benghazi, Benghazi, Libya.

DOI:

https://doi.org/10.59743/jmset.v1i2.119

Keywords:

Nummulites vascus, Late Oligocene, Abraq formation, Northeast Libya

Abstract

Spherical calcite chamber-like objects of almost identical size have been found in a few tests of Nummulites vascus. These Nummulites constitute the dominant benthic foraminifera assembly among the reported foraminiferal assemblage of the Abraq Formation (Late Oligocene) at the Daryanah- Al Abyar Roadcut in Northeast Libya. These structures are identified as brood chambers or cysts formed during reproduction and retained within the mother test, where the embryos were hosted during life. The possibility of a diagenetic origin to these cysts is excluded due to the hollow-nature of these objects which supports a biotic origin rather than diagenesis. Similarly, a symbiotic relationship with microalga is also excluded due to the lack of any cellular microstructure. The existence of calcitic brood chambers in Nummulites is hitherto unknown. Importantly this sample appears to be the first example of a calcified brood pouch fossil or ‘cyst’ in Nummulites (23– 28 Ma) research.

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