REVIEWING THE MODERN LARGER BENTHIC FORAMINIFERA DIVERSITY AND DEFORMITIES IN THE HYPERSALINE ARABIAN GULF: WHAT DO WE KNOW BASED ON ECOLOGICAL UPDATES?

Between the 1960s and the 1970s, Professor John Murray conducted a number of studies on foraminifera in the Arabian Gulf's hypersaline coastal and shallow marine environments. The foraminiferal families Soritidae, Peneroplidae, and Nummulitidae are the principal contributors to the Larger Benthic Foraminifera (LBF) assemblage in the region, with the genus Peneroplis being the most notable, according to Murray's six key publications.

This study aims to build upon Murray's findings by looking at numerous relevant studies that have since been conducted, and it is further reinforced by field sampling operations in Saudi Arabia and Bahrain that are concentrated in regions with varying salinity levels. Additionally, we considered the unusual morphologies typically observed in the Gulf. Several important conclusions may be drawn from our review of 34 published and unpublished studies on LBF throughout the whole of the Arabian Gulf (excluding Murray's works). The first findings are two new LBF families: Alveolinidae and Amphisteginidae, increasing the total number to five families when compared to prior reports. Second findings are that Peneroplis, notably the species P. pertusus and P. planatus, are the most frequent and ubiquitous group in the samples, followed by a Coscinospira species in the Arabian Gulf (C. hemprichii). Only 7 out of 34 publications mention abnormalities among LBF, according to our third finding. Our field sample data of LBF from three locations (East Bahrain, Half Moon Bay, and Al-Uqayr) not only cover the gap of some unknown regions, but also show that more than 40% of specimens are deformed, and furthermore, the proportion of deformities rises as salinity increases. As well as pushing Coscinospira assemblages towards Peneroplis, juvenile or undeveloped later stage specimens (which nonetheless have abnormalities) typically have fewer malformations than adult or better developed younger stage specimens.

Intriguing questions about future research in the Gulf have been sparked by these results and our recent discoveries, including how diverse the LBF are, what causes morphological deformities in a hypersaline environment, and the resilience of the foraminifera despite the initial assessment that they are less diverse.