Annals of Human Biology, May–June 2010; 37(3): 288–311 REVIEW ARTICLE Out of Africa: new hypotheses and evidence for the dispersal of Homo sapiens along the Indian Ocean rim MICHAEL D. PETRAGLIA 1 , MICHAEL HASLAM 1 , DORIAN Q. FULLER 2 , NICOLE BOIVIN 1 & CHRIS CLARKSON 3 1 School of Archaeology, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, UK, 2 Institute of Archaeology, University College London, London, UK, and 3 School of Social Science, University of Queensland, St Lucia, Queensland, Australia (Received 14 January 2010; accepted 19 January 2010) Abstract The dispersal of Homo sapiens out of Africa is a significant topic in human evolutionary studies. Most investigators agree that our species arose in Africa and subsequently spread out to occupy much of Eurasia. Researchers have argued that populations expanded along the Indian Ocean rim at ca 60 000 years ago during a single rapid dispersal event, probably employing a coastal route towards Australasia. Archaeologists have been relatively silent about the movement and expansion of human populations in terrestrial environments along the Indian Ocean rim, although it is clear that Homo sapiens reached Australia by ca 45 000 years ago. Here, we synthesize and document current genetic and archaeological evidence from two major landmasses, the Arabian peninsula and the Indian subcontinent, regions that have been underplayed in the story of out of Africa dispersals. We suggest that modern humans were present in Arabia and South Asia earlier than currently believed, and probably coincident with the presence of Homo sapiens in the Levant between ca 130 and 70 000 years ago. We show that climatic and environmental fluctuations during the Late Pleistocene would have had significant demographic effects on Arabian and South Asian populations, though indigenous popula- tions would have responded in different ways. Based on a review of the current genetic, archaeological and environmental data, we indicate that demographic patterns in Arabia and South Asia are more interesting and complex than surmised to date. Keywords: Dispersals, Homo sapiens, Indian Ocean, Arabia, South Asia Introduction Questions about the origins of Homo sapiens and the spread of humans around the world fascinate scholars and the general public alike. In recent years, the broad outline of the Correspondence: Michael D. Petraglia, School of Archaeology, Research Laboratory for Archaeology and the History of Art, University of Oxford, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK. E-mail: michael.petraglia@rlaha.ox.ac.uk ISSN 0301-4460 print/ISSN 1464-5033 online Ó 2010 Informa UK Ltd. DOI: 10.3109/03014461003639249 Ann Hum Biol Downloaded from informahealthcare.com by The Keeper of Scientific Books on 09/03/10 For personal use only.