Articles | Volume 37, issue 1
https://doi.org/10.5194/jm-37-149-2018
https://doi.org/10.5194/jm-37-149-2018
Research article
 | 
11 Jan 2018
Research article |  | 11 Jan 2018

The occurrence of a shallow-water Ammobaculoides assemblage in the Middle Jurassic (Bajocian) Dhruma Formation of Central Saudi Arabia

Michael A. Kaminski, Muhammad Hammad Malik, and Eiichi Setoyama

Abstract. We report the occurrence of an Ammobaculoides-dominated assemblage in the lowermost member of the Middle Jurassic Dhruma Formation exposed west of Riyadh, Saudi Arabia. The new species Ammobaculoides dhrumaensis n.sp. is described from the green shale of the D1 unit (also known as the Balum Member) of the Dhruma Formation, which has been assigned an early Bajocian age based on ammonites. Our new finding constitutes the oldest reported worldwide occurrence of the agglutinated foraminiferal genus Ammobaculoides Plummer, 1932.

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Short summary
We report the occurrence of a foraminiferal assemblage dominated by Ammobaculoides in the lowermost member of the Middle Jurassic Dhruma Formation exposed west of Riyadh, Saudi Arabia. The new species Ammobaculoides dhrumaensis n.sp. is described from the D1 unit (the Balum Member) of the Dhruma Formation, which has been assigned an early Bajocian age based on ammonites. Our new finding constitutes the oldest reported worldwide occurrence of the agglutinated foraminiferal genus Ammobaculoides.