A taxonomic and taphonomic study of Pleistocene fossil deposits from the western Nefud Desert, Saudi Arabia

Over the past decade, a growing interest has developed on the archaeology, palaeontology, and palaeoenvironments of the Arabian Peninsula. It is now clear that hominins repeatedly dispersed into Arabia, notably during pluvial interglacial periods when much of the peninsula was characterised by a semiarid grassland environment. During the intervening glacial phases, however, grasslands were replaced with arid and hyperarid deserts. These millennial-scale climatic fluctuations have subjected bones and fossils to a dramatic suite of environmental conditions, affecting their fossilisation and preservation. Yet, as relatively few palaeontological assemblages have been reported from the Pleistocene of Arabia, our understanding of the preservational pathways that skeletal elements can take in these types of environments is lacking. Here, we report the first widespread taxonomic and taphonomic assessment of Arabian fossil deposits. Novel fossil fauna are described and overall the fauna are consistent with a well-watered semiarid grassland environment. Likewise, the taphonomic results suggest that bones were deposited under more humid conditions than present in the region today. However, fossils often exhibit significant attrition, obscuring and fragmenting most finds. These are likely tied to wind abrasion, insolation, and salt weathering following fossilisation and exhumation, processes particularly prevalent in desert environments

Coring, profiling, and trenching: Archaeological field strategies for investigating the Pleistocene-Holocene-Anthropocene continuum

Archaeologists have long emphasized the importance of large-scale excavations and multi-year or even decades-long projects at a single site or site complex. Here, we highlight archaeological field strategies, termed coring, profiling, and trenching (CPT), that rely on relatively small-scale excavations or the collection of new samples from intact deposits in previously excavated trenches (aka test units or pits). Examples from multiple sites in Africa, Asia, and North America demonstrate that CPT is highly effective for obtaining high-resolution archaeobiological and geoarchaeological samples (e.g., faunal and botanical remains, sediments) and artefacts from areas that have seen limited or no archaeological research, little systematic application of archaeological science methods, or research only on a relatively narrow time period or geographic scale. Designed to complement large-scale excavations at single sites, CPT is ideal for multi-scalar research that works in tandem with remote sensing techniques, providing samples for detailed laboratory analyses and offering a bridge between surface surveys and large-scale excavation. Given the threats facing archaeological sites around the world from climate change and human development, as well as financial, training and infrastructure constraints, and concerns from many Indigenous communities about large excavations, we argue that CPT is an important method for addressing 21st century human-environmental research questions

Rock art imagery as a proxy for Holocene environmental change: A view from Shuwaymis, NW Saudi Arabia

The animal species depicted in the rock art of Shuwaymis, Saudi Arabia, provide a record of Holocene climatic changes, as seen by the engravers. Of 1903 animal engravings, 1514 contained sufficient detail to allow identification with confidence. In addition, the stratigraphy of the engravings and the depiction of domesticates provide a broad chronological framework that allows a division into images created during the Holocene humid phase and animals represented after the onset of desert conditions. Despite the large sample size, only 16 animal species could be identified, which represents an extraordinarily narrow species spectrum. Comparison with the scarce faunal record of the Arabian Peninsula shows that all larger animals that are thought to have been present in the area were also depicted in the rock art. The contemporaneous presence of at least four large carnivores during the Holocene humid phase suggests that prey animals were abundant, and that the landscape consisted of a mosaic of habitats, potentially with thicker vegetation along the water courses of the wadis and more open vegetation in the landscape around them. Community Earth System Models (COSMOS) climate simulations show that Shuwaymis was at the northern edge of the African Summer Monsoon rainfall regime. It is therefore possible that Shuwaymis was ecologically connected with southwestern Arabia, and that an arid barrier remained in place to the north, restricting the dispersal of Levantine species into Arabia

Taphonomic and zooarchaeological investigations at the middle Pleistocene site of Ti's al Ghadah, western Nefud Desert, Saudi Arabia

In recent years, the Arabian Peninsula has emerged as a key region for elucidating hominin and faunal evolution and dispersals between Africa and Eurasia. Central to this research is the middle Pleistocene site of Ti's al Ghadah (TAG) which has yielded a diverse and abundant fossil faunal assemblage and the earliest chronometrically dated evidence for hominins in this part of the world. Here, we present the first detailed taphonomic study of the large Unit 5 fossil assemblage from the site. We aim to assess which actor/s were responsible for the accumulation of the assemblage and evaluate evidence that might be consistent with the accumulation of fauna by hominins. We also describe, for the first time, fossils and lithic artefacts from stratigraphic horizons not previously considered, providing taphonomic insights into their accumulation. The taphonomic work shows that the Unit 5 faunal assemblage was accumulated by ambush predators, likely large felids and hominins, in a lake side environment, and that carcasses were subsequently scavenged by more durophagus carnivores such as hyenas and canids. Less can be reliably said regarding the newly described fossil assemblages given their poor preservation and significant wind abrasion, but large carnivores again appear to have played a role, and hominins probably played a role in the accumulation of at least one of these. This study provides the first detail insights into the interplay between hominins, carnivores, and herbivores in Arabia, and suggests that watering holes have been a focus on the Arabian landscape for resources since the middle Pleistocene

Real-world evidence of the effects of sodium-glucose co-transporter 2 inhibitors on the dosing of diuretics in patients with heart failure: a retrospective cohort study

Background: Heart failure (HF) was estimated to impact approximately 64 million individuals worldwide in 2017 and is predicted to rise in the coming years. Therefore, the aim of our study was to evaluate the effects of sodium-glucose transport protein 2 (SGLT2) inhibitors on the dosing of diuretics among individuals diagnosed with HF.Methods: A retrospective cohort study was conducted at Security Forces Hospital in Riyadh, Saudi Arabia, between January 2018 and August 2022. The study included adult patients who were diagnosed with heart failure and received dapagliflozin and/or diuretic. A descriptive analysis was conducted to identify significant differences between both groups by using the chi-square test for categorical variables and the Student’s t-test for continuous variables. A logistic regression model was also run to identify the odds of each event. Statistical significance was indicated by p values less than .05.Results: Overall reduction in diuretics was reported in 68 patients in the SGLT2 inhibitors plus diuretic therapy group, while in the diuretic therapy group 25 patients reported overall reduction in diuretics (OR = 4.81, 95% [2.74–8.45]). The reduction of the loop dose level was reported by 58 patients in the SGLT2 inhibitors plus diuretic group and by 25 patients in the diuretic group (OR = 3.48, 95% [1.98–6.11]). The discontinuation of thiazide was reported by 16 patients in the SGLT2 inhibitors plus diuretic therapy group, but by only two patients in the diuretic group (OR = 9.04, 95% [2.03–40.19]). After 6 months, ejection fraction was increased by 2.74 in the SGLT2 inhibitors plus diuretic group (p = .0019) and decreased by 2.56 in the diuretic group (p = .0485), both of which were statistically significant. The mean dose changes were decreased by 14.52 in the SGLT2 inhibitors plus diuretic group (p < .0001), which was statistically significant.Conclusion: Treatment with SGLT2 inhibitors plus diuretic significantly reduced the patients’ diuretic requirements. Therefore, our finding supports the theoretical concept of minimizing the level of diuretic upon the initiation of SGLT2 inhibitors

First evidence for human occupation of a lava tube in Arabia: The archaeology of Umm Jirsan Cave and its surroundings, northern Saudi Arabia

Recent advances in interdisciplinary archaeological research in Arabia have focused on the evolution and historical development of regional human populations as well as the diverse patterns of cultural change, migration, and adaptations to environmental fluctuations. Obtaining a comprehensive understanding of cultural developments such as the emergence and lifeways of Neolithic groups has been hindered by the limited preservation of stratified archaeological assemblages and organic remains, a common challenge in arid environments. Underground settings like caves and lava tubes, which are prevalent in Arabia but which have seen limited scientific exploration, offer promising opportunities for addressing these issues. Here, we report on an archaeological excavation and a related survey at and around Umm Jirsan lava tube in the Harrat Khaybar, north-western Saudi Arabia. Our results reveal repeated phases of human occupation of the site ranging from at least the Neolithic through to the Chalcolithic/Bronze Age. Pastoralist use of the lava tube and surrounding landscape is attested in rock art and faunal records, suggesting that Umm Jirsan was situated along a pastoral route linking key oases. Isotopic data indicates that herbivores primarily grazed on wild grasses and shrubs rather than being provided with fodder, while humans had a diet consistently high in protein but with increasing consumption of C3 plants through-time, perhaps related to the emergence of oasis agriculture. While underground and naturally sheltered localities are globally prominent in archaeology and Quaternary science, our work represents the first such combined records for Saudi Arabia and highlight the potential for interdisciplinary studies in caves and lava tubes

Homo sapiens in Arabia by 85,000 years ago

Understanding the timing and character of Homo sapiens expansion out of Africa is critical for inferring the colonisation and admixture processes that underpin global population history. It has been argued that dispersal out of Africa had an early phase, particularly ~130-90 thousand years ago (ka), that only reached the East Mediterranean Levant, and a later phase, ~60-50 ka, that extended across the diverse environments of Eurasia to Sahul. However, recent findings from East Asia and Sahul challenge this model. Here we show that H. sapiens was in the Arabian Peninsula before 85 ka. We describe the Al Wusta-1 (AW-1) intermediate phalanx from the site of Al Wusta in the Nefud Desert, Saudi Arabia. AW-1 is the oldest directly dated fossil of our species outside Africa and the Levant. The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna. A Bayesian model incorporating independent chronometric age estimates indicates a chronology for Al Wusta of ~95-86 ka, which we correlate with a humid episode in the later part of Marine Isotope Stage 5 known from various regional records. Al Wusta shows that early dispersals were more spatially and temporally extensive than previously thought. Early H. sapiens dispersals out of Africa were not limited to winter rainfall-fed Levantine Mediterranean woodlands immediately adjacent to Africa, but extended deep into the semi-arid grasslands of Arabia, facilitated by periods of enhanced monsoonal rainfall

Homo sapiens in Arabia by 85,000 years ago.

Understanding the timing and character of the expansion of Homo sapiens out of Africa is critical for inferring the colonization and admixture processes that underpin global population history. It has been argued that dispersal out of Africa had an early phase, particularly ~130-90 thousand years ago (ka), that reached only the East Mediterranean Levant, and a later phase, ~60-50 ka, that extended across the diverse environments of Eurasia to Sahul. However, recent findings from East Asia and Sahul challenge this model. Here we show that H. sapiens was in the Arabian Peninsula before 85 ka. We describe the Al Wusta-1 (AW-1) intermediate phalanx from the site of Al Wusta in the Nefud desert, Saudi Arabia. AW-1 is the oldest directly dated fossil of our species outside Africa and the Levant. The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna. A Bayesian model incorporating independent chronometric age estimates indicates a chronology for Al Wusta of ~95-86 ka, which we correlate with a humid episode in the later part of Marine Isotope Stage 5 known from various regional records. Al Wusta shows that early dispersals were more spatially and temporally extensive than previously thought. Early H. sapiens dispersals out of Africa were not limited to winter rainfall-fed Levantine Mediterranean woodlands immediately adjacent to Africa, but extended deep into the semi-arid grasslands of Arabia, facilitated by periods of enhanced monsoonal rainfall

Multiple hominin dispersals into Southwest Asia over the past 400,000 years.

Pleistocene hominin dispersals out of, and back into, Africa necessarily involved traversing the diverse and often challenging environments of Southwest Asia1-4. Archaeological and palaeontological records from the Levantine woodland zone document major biological and cultural shifts, such as alternating occupations by Homo sapiens and Neanderthals. However, Late Quaternary cultural, biological and environmental records from the vast arid zone that constitutes most of Southwest Asia remain scarce, limiting regional-scale insights into changes in hominin demography and behaviour1,2,5. Here we report a series of dated palaeolake sequences, associated with stone tool assemblages and vertebrate fossils, from the Khall Amayshan 4 and Jubbah basins in the Nefud Desert. These findings, including the oldest dated hominin occupations in Arabia, reveal at least five hominin expansions into the Arabian interior, coinciding with brief 'green' windows of reduced aridity approximately 400, 300, 200, 130-75 and 55 thousand years ago. Each occupation phase is characterized by a distinct form of material culture, indicating colonization by diverse hominin groups, and a lack of long-term Southwest Asian population continuity. Within a general pattern of African and Eurasian hominin groups being separated by Pleistocene Saharo-Arabian aridity, our findings reveal the tempo and character of climatically modulated windows for dispersal and admixture

Red Sea palaeoclimate: stable isotope and element-ratio analysis of marine mollusc shells

The southern Red Sea coast is the location of more than 4,200 archaeological shell midden sites. These shell middens preserve archaeological and climatic archives of unprecedented resolution and scale. By using shells from these contexts, it is possible to link past environmental information with episodes of human occupation and resource processing. This chapter summarises current knowledge about the marine gastropod Conomurex fasciatus (Born 1778) and discusses its use in environmental and climatic reconstruction using stable isotope and elemental ratio analysis. It offers a review of the most recent studies of shell midden sites on the Farasan Islands, their regional importance during the mid-Holocene, theories about seasonal use of the coastal landscape, and preliminary results from new methods to acquire large climatic datasets from C. fasciatus shells