Rémy Crassard

Bio: Rémy Crassard is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Prehistory & Lithic technology. The author has an hindex of 22, co-authored 72 publications receiving 1411 citations. Previous affiliations of Rémy Crassard include Centre for Environment, Fisheries and Aquaculture Science & University of Cambridge.

Hominin Dispersal into the Nefud Desert and Middle Palaeolithic Settlement along the Jubbah Palaeolake, Northern Arabia

Abstract: The Arabian Peninsula is a key region for understanding hominin dispersals and the effect of climate change on prehistoric demography, although little information on these topics is presently available owing to the poor preservation of archaeological sites in this desert environment Here, we describe the discovery of three stratified and buried archaeological sites in the Nefud Desert, which includes the oldest dated occupation for the region The stone tool assemblages are identified as a Middle Palaeolithic industry that includes Levallois manufacturing methods and the production of tools on flakes Hominin occupations correspond with humid periods, particularly Marine Isotope Stages 7 and 5 of the Late Pleistocene The Middle Palaeolithic occupations were situated along the Jubbah palaeolake-shores, in a grassland setting with some trees Populations procured different raw materials across the lake region to manufacture stone tools, using the implements to process plants and animals To reach the Jubbah palaeolake, Middle Palaeolithic populations travelled into the ameliorated Nefud Desert interior, possibly gaining access from multiple directions, either using routes from the north and west (the Levant and the Sinai), the north (the Mesopotamian plains and the Euphrates basin), or the east (the Persian Gulf) The Jubbah stone tool assemblages have their own suite of technological characters, but have types reminiscent of both African Middle Stone Age and Levantine Middle Palaeolithic industries Comparative inter-regional analysis of core technology indicates morphological similarities with the Levantine Tabun C assemblage, associated with human fossils controversially identified as either Neanderthals or Homo sapiens

Middle Palaeolithic and Neolithic occupations around Mundafan Palaeolake, Saudi Arabia: Implications for climate change and human dispersals

Abstract: The Arabian Peninsula is a key region for understanding climate change and human occupation history in a marginal environment. The Mundafan palaeolake is situated in southern Saudi Arabia, in the Rub' al-Khali (the 'Empty Quarter'), the world's largest sand desert. Here we report the first discoveries of Middle Palaeolithic and Neolithic archaeological sites in association with the palaeolake. We associate the human occupations with new geochronological data, and suggest the archaeological sites date to the wet periods of Marine Isotope Stage 5 and the Early Holocene. The archaeological sites indicate that humans repeatedly penetrated the ameliorated environments of the Rub' al-Khali. The sites probably represent short-term occupations, with the Neolithic sites focused on hunting, as indicated by points and weaponry. Middle Palaeolithic assemblages at Mundafan support a lacustrine adaptive focus in Arabia. Provenancing of obsidian artifacts indicates that Neolithic groups at Mundafan had a wide wandering range, with transport of artifacts from distant sources.

The Impact of Climate Change on Mangrove Forests

Abstract: Mangrove forests have survived a number of catastrophic climate events since first appearing along the shores of the Tethys Sea during the late Cretaceous-Early Tertiary. The existence of mangrove peat deposits worldwide attests to past episodes of local and regional extinction, primarily in response to abrupt, rapid rises in sea level. Occupying a harsh margin between land and sea, most mangrove plants and associated organisms are predisposed to be either resilient or resistant to most environmental change. Based on the most recent Intergovernmental Panel on Climate Change (IPCC) forecasts, mangrove forests along arid coasts, in subsiding river deltas, and on many islands are predicted to decline in area, structural complexity, and/or in functionality, but mangroves will continue to expand polewards. It is highly likely that they will survive into the foreseeable future as sea level, global temperatures, and atmospheric CO2 concentrations continue to rise.

Rethinking the dispersal of Homo sapiens out of Africa.

Abstract: Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa in the late Middle Pleistocene. By the end of the Late Pleistocene, our species was distributed across every continent except Antarctica, setting the foundations for the subsequent demographic and cultural changes of the Holocene. The intervening processes remain intensely debated and a key theme in hominin evolutionary studies. We review archeological, fossil, environmental, and genetic data to evaluate the current state of knowledge on the dispersal of Homo sapiens out of Africa. The emerging picture of the dispersal process suggests dynamic behavioral variability, complex interactions between populations, and an intricate genetic and cultural legacy. This evolutionary and historical complexity challenges simple narratives and suggests that hybrid models and the testing of explicit hypotheses are required to understand the expansion of Homo sapiens into Eurasia.

Genetic and archaeological perspectives on the initial modern human colonization of southern Asia

Abstract: It has been argued recently that the initial dispersal of anatomically modern humans from Africa to southern Asia occurred before the volcanic “supereruption” of the Mount Toba volcano (Sumatra) at ∼74,000 y before present (B.P.)—possibly as early as 120,000 y B.P. We show here that this “pre-Toba” dispersal model is in serious conflict with both the most recent genetic evidence from both Africa and Asia and the archaeological evidence from South Asian sites. We present an alternative model based on a combination of genetic analyses and recent archaeological evidence from South Asia and Africa. These data support a coastally oriented dispersal of modern humans from eastern Africa to southern Asia ∼60–50 thousand years ago (ka). This was associated with distinctively African microlithic and “backed-segment” technologies analogous to the African “Howiesons Poort” and related technologies, together with a range of distinctively “modern” cultural and symbolic features (highly shaped bone tools, personal ornaments, abstract artistic motifs, microblade technology, etc.), similar to those that accompanied the replacement of “archaic” Neanderthal by anatomically modern human populations in other regions of western Eurasia at a broadly similar date.

On the origin of modern humans: Asian perspectives

Abstract: BACKGROUND The earliest fossils of Homo sapiens are located in Africa and dated to the late Middle Pleistocene. At some point later, modern humans dispersed into Asia and reached the far-away locales of Europe, Australia, and eventually the Americas. Given that Neandertals, Denisovans, mid-Pleistocene Homo , and H. floresiensis were present in Asia before the appearance of modern humans, the timing and nature of the spread of modern humans across Eurasia continue to be subjects of intense debate. For instance, did modern humans replace the indigenous populations when moving into new regions? Alternatively, did population contact and interbreeding occur regularly? In terms of behavior, did technological innovations and symbolism facilitate dispersals of modern humans? For example, it is often assumed that only modern humans were capable of using watercraft and navigating to distant locations such as Australia and the Japanese archipelago—destinations that would not have been visible to the naked eye from the departure points, even during glacial stages when sea levels would have been much lower. Moreover, what role did major climatic fluctuations and environmental events (e.g., the Toba volcanic super-eruption) play in the dispersal of modern humans across Asia? Did extirpations of groups occur regularly, and did extinctions of populations take place? Questions such as these are paramount in understanding hominin evolution and Late Pleistocene Asian paleoanthropology. ADVANCES An increasing number of multidisciplinary field and laboratory projects focused on archaeological sites and fossil localities from different areas of Asia are producing important findings, allowing researchers to address key evolutionary questions that have long perplexed the field. For instance, technological advances have increased our ability to successfully collect ancient DNA from hominin fossils, providing proof that interbreeding occurred on a somewhat regular basis. New finds of H. sapiens fossils, with increasingly secure dating associations, are emerging in different areas of Asia, some seemingly from the first half of the Late Pleistocene. Cultural variability discerned from archaeological studies indicates that modern human behaviors did not simply spread across Asia in a time-transgressive pattern. This regional variation, which is particularly distinct in Southeast Asia, could be related at least in part to environmental and ecological variation (e.g., Palearctic versus Oriental biogeographic zones). OUTLOOK Recent findings from archaeology, hominin paleontology, geochronology, and genetics indicate that the strict “out of Africa” model, which posits that there was only a single dispersal into Eurasia at ~60,000 years ago, is in need of revision. In particular, a multiple-dispersal model, perhaps beginning at the advent of the Late Pleistocene, needs to be examined more closely. An increasingly robust record from Late Pleistocene Asian paleoanthropology is helping to build and establish new views about the origin and dispersal of modern humans.