First report of modern planktonic foraminifera in the southeastern Arabian Gulf, with observations on the morphology and ecology of Neogallitellia vivans (Cushman)

This study reports the first documented occurrence of planktonic foraminiferal assemblages from core and grab samples collected from the United Arab Emirates (UAE) sector of the Arabian Gulf, specifically from offshore Abu Dhabi. Although planktonic foraminifera were found at only 4 out of 20 surveyed sites, representing less than 5 % of the total foraminiferal assemblage, their presence is notable. This finding demonstrates that planktonic foraminifera can be found far from their typical habitat near the oceanic inlet to the semi-enclosed Arabian Gulf – the Strait of Hormuz. The recovered material includes at least five species (three true planktonic foraminifera, one with a planktonic adult stage, and one incertae sedis): Neogallitellia vivans, Globigerinoides tenellus, and Turborotalita clarkei, as well as the benthic–planktonic species Tretomphalus bulloides and a planktonic taxon of uncertain origin described under the name Bachmayerella sp. The species N. vivans dominates in the studied samples, comprising over 90 % of the planktonic assemblage; however, their small size means that most specimens are not retained on a 125 µm sieve. This work is part of a broader project to re-examine localities in the southeastern Arabian Gulf that were previously studied for benthic foraminifera, as well as to explore areas further offshore, which were previously uncharted for their foraminiferal content (particularly for the presence of planktonic foraminifera).