Beyond the reef: A baseline characterization of the mid-outer shelf benthic foraminifera from the southern Red Sea (Yemen) and their environmental controls
Muaamar, R.M.; Al-Wosabi, M.A.; Al-Subbary, A.A.; Hewaidy, A.G.A.; Bazeen, Y.S. (2026). Beyond the reef: A baseline characterization of the mid-outer shelf benthic foraminifera from the southern Red Sea (Yemen) and their environmental controls. Thalassas 42(2): 140. https://dx.doi.org/10.1007/s41208-026-01139-8
In: Thalassas. Universidad de Vigo: Vigo. ISSN 0212-5919; e-ISSN 2366-1674, more
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| Keywords |
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| Author keywords |
Deep shelf benthic foraminifera · Taxonomic richness hotspot · Multivariate analysis |
| Authors | | Top |
- Muaamar, R.M.
- Al-Wosabi, M.A.
- Al-Subbary, A.A.
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- Hewaidy, A.G.A.
- Bazeen, Y.S.
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| Abstract |
A preliminary quantitative survey of recent benthic foraminiferal assemblages from six stations (mid to outer shelf; 50–200 m) off the Yemeni coast of the Red Sea is attempted here to document benthic foraminiferal diversity and spatial assemblage patterns across such understudied sector of the Red Sea. A total of 156 benthic foraminiferal species were identified, representing the highest documented taxonomic richness for the region. Species richness per station (56–97; mean 80) is more than double that reported from earlier shallow-water surveys, underscoring the deeper Yemeni shelf as a taxonomic richness hotspot. Crucially, these mid-outer shelf assemblages differ fundamentally from shallow Red Sea communities through: (1) significant agglutinated components (mean ∼10.3%, up to 32.1%) that are absent in nearshore studies; (2) scarce symbiont-bearing taxa (< 10%); and (3) the first regional records of taxa including Reophax spp., and Cibicides wuellerstorfi. Multivariate analyses (Q-mode clustering and NMDS) identified three biofacies: (i) carbonate-rich, well-flushed mid-shelf sites (50–89 m) with high species richness and mixed hyaline–porcelaneous assemblages; (ii) sheltered outer-shelf sites (107–176 m) within the axial corridor with intermediate species richness and stress signals; and (iii) a deeper site (190 m; near Bab al-Mandab) dominated by specialized agglutinated taxa (Reophax, Textularia). A defining feature of the recognized Yemeni assemblages is the persistence of porcelaneous miliolids (~ 39.3%) at distal depths, which is in line with the “isothermal warm-basin” character of the Red Sea. The recognized assemblage patterns are interpreted as controlled mainly by bathymetry and episodic organic/oxygen stress (e.g., influence of Bab al-Mandab inflow). Given the limited sample size, these results provide a preliminary but robust, time-averaged baseline for the understudied southern Yemeni Red Sea and highlight priorities for further sampling and in situ environmental measurements. |
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