Public release date: 30-Nov-2011
Contact: Yael Franco
Public Library of Science
Trail of 'stone breadcrumbs' reveals the identity of 1 of the first human groups to leave Africa
A series of new archaeological discoveries in the Sultanate of Oman, nestled in the southeastern corner of the Arabian Peninsula, reveals the timing and identity of one of the first modern human groups to migrate out of Africa, according to a research article published in the open-access journal PLoS ONE.
An international team of archaeologists and geologists working in the Dhofar Mountains of southern Oman, led by Dr. Jeffrey Rose of the University of Birmingham, report finding over 100 new sites classified as "Nubian Middle Stone Age (MSA)." Distinctive Nubian MSA stone tools are well known throughout the Nile Valley; however, this is the first time such sites have ever been found outside of Africa.
According to the authors, the evidence from Oman provides a "trail of stone breadcrumbs" left by early humans migrating across the Red Sea on their journey out of Africa. "After a decade of searching in southern Arabia for some clue that might help us understand early human expansion, at long last we've found the smoking gun of their exit from Africa," says Rose. "What makes this so exciting," he adds, "is that the answer is a scenario almost never considered."
These new findings challenge long-held assumptions about the timing and route of early human expansion out of Africa. Using a technique called Optically Stimulated Luminescence (OSL) to date one of the sites in Oman, researchers have determined that Nubian MSA toolmakers had entered Arabia by 106,000 years ago, if not earlier. This date is considerably older than geneticists have put forth for the modern human exodus from Africa, who estimate the dispersal of our species occurred between 70,000 and 40,000 years ago.
Even more surprising, all of the Nubian MSA sites were found far inland, contrary to the currently accepted theory that envisions early human groups moving along the coast of southern Arabia. "Here we have an example of the disconnect between theoretical models versus real evidence on the ground," says co-author Professor Emeritus Anthony Marks of Southern Methodist University. "The coastal expansion hypothesis looks reasonable on paper, but there is simply no archaeological evidence to back it up. Genetics predict an expansion out of Africa after 70,000 thousand years ago, yet we've seen three separate discoveries published this year with evidence for humans in Arabia thousands, if not tens of thousands of years prior to this date."
The presence of Nubian MSA sites in Oman corresponds to a wet period in Arabia's climatic history, when copious rains fell across the peninsula and transformed its barren deserts to sprawling grasslands. "For a while," remarks Rose, "South Arabia became a verdant paradise rich in resources – large game, plentiful freshwater, and high-quality flint with which to make stone tools." Far from innovative fishermen, it seems that early humans spreading from Africa into Arabia were opportunistic hunters traveling along river networks like highways. Whether or not these pioneers were able to survive in Arabia during the hyperarid conditions of the Last Ice Age is another matter – a mystery that will require archaeologists to continue combing the deserts of southern Arabia, hot on the trail of stone breadcrumbs.
###The Dhofar Archaeological Project is conducted under the auspices of the Ministry of Heritage and Culture in Oman. The team is comprised of an interdisciplinary group of researchers from the University of Birmingham and Oxford Brookes University, UK; Arizona State University and Southern Methodist University, USA; Institute of Archaeology, National Academy of Sciences, Ukraine; Institute of Archaeology of the Academy of Science, Czech Republic; University of Tübingen, Germany, and the University of Wollongong, Australia. The project is funded by research grants from the UK Arts and Humanities Research Council and the Australian Research Council.
Citation: Rose JI, Usik VI, Marks AE, Hilbert YH, Galletti CS, et al. (2011) The Nubian Complex of Dhofar, Oman: An African Middle Stone Age Industry in Southern Arabia. PLoS ONE 6(11): e28239.doi:10.1371/journal.pone.0028239
Financial Disclosure: The Dhofar Archaeological Project fieldwork and analysis is funded by an Early Career Research grant from the UK Arts and Humanities Research Council (AH/H033912/1): www.ahrc.ac.uk. Funding for OSL dating comes from the Australian Research Council (DP0880675): www.arc.gov.au. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interest Statement: The authors have declared that no competing interests exist.
Disclaimer: This press release refers to upcoming articles in PLoS ONE. The releases have been provided by the article authors and/or journal staff. Any opinions expressed in these are the personal views of the contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the release and article and your use of such information.
About PLoS ONE
PLoS ONE is the first journal of primary research from all areas of science to employ a combination of peer review and post-publication rating and commenting, to maximize the impact of every report it publishes. PLoS ONE is published by the Public Library of Science (PLoS), the open-access publisher whose goal is to make the world's scientific and medical literature a public resource.
All works published in PLoS ONE are Open Access. Everything is immediately available—to read, download, redistribute, include in databases and otherwise use—without cost to anyone, anywhere, subject only to the condition that the original authors and source are properly attributed. For more information about PLoS ONE relevant to journalists, bloggers and press officers, including details of our press release process and our embargo policy, see the EveryONE blog at http://everyone.plos.org/media.