New Evidence from East Timor Contributes to Our Understanding of Earliest Modern Human Colonisation East of the Sunda Shelf

Article excerpt

New dates by which modern humans reached East Timor prompts this very useful update of the colonisation of Island Southeast Asia. The author addresses all the difficult questions: why are the dates for modern humans in Australia earlier than they are in Island Southeast Asia? Which route did they use to get there? If they used the southern route, why or how did they manage to bypass Flores, where Homo floresiensis, the famous non-sapiens hominin known to the world as the 'hobbit' was already in residence? New work at the rock shelter of Jerimalai suggests some answers and new research directions.

Keywords: Pleistocene, Island Southeast Asia, East Timor, Homo sapiens, Homo floresiensis, human colonization

Introduction

This paper reports new finds from Timor, where a habitation site dated to >42 000 cal BP (38 255 [+ or -] 596 bp) provides the earliest evidence for migration by modern humans east of the Sunda Shelf into Island Southeast Asia. Until now there has been a major discrepancy between the dates for earliest occupation in Australia and those from Island Southeast Asia, with the earliest dated sites from Australia being significantly older than the oldest sites from any of the potential stepping stone islands en route (even relying purely on the radiocarbon chronology) (Bellwood 1998; O'Connor & Chappell 2003; summarised on Figure 1). Although a southern route through the Lesser Sunda islands (including Flores and Timor) has usually been proposed as the most parsimonious for maritime passage to Sahul (the ancient continent that encompassed Australia and New Guinea) (Birdsell 1977; Butlin 1993:15, 44-51), the lack of early dated evidence on any of the stepping stone islands of this group has led some authors to propose alternative routes (albeit equally lacking in evidence for early colonisation).

Perhaps the greatest recent challenge to the southern route has been posed by the recent finds from Flores, Timor's western neighbour island, where modern humans apparently failed to colonise prior to the Holocene (Brumm et al. 2006). The new dates and data from Jerimalai shelter in East Timor redresses this situation, and indicate that the southern route is still a strong contender for the earliest seafaring passage to Sahul. With moderns humans firmly ensconced in Australia by this time, it would not previously have been considered necessary to argue the case that a site of this age was the product of modern human behaviour; especially one on an island requiring a water crossing to reach it (Davidson & Noble 1992; Brumm & Moore 2005: 159). But the fact that a non-modern hominin was present on Flores until 12 000 years ago changes this. In the absence of human skeletal remains, the nature of the occupation evidence from Timor is evaluated in order to demonstrate that it is qualitatively different from the assemblage produced by non-moderns from the late Pleistocene context at Liang Bua, as well as for its significance in contributing to our understanding of the types of adaptations made at this early date on route to Sahul.

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Dating colonisation

The date for initial human peopling of Australia is now widely accepted to have occurred between 50 000 and 60 000 years ago (Roberts et al. 1990; 1994; 1998; Thorne et al. 1999; O'Connor & Chappell 2003). However it should be kept in mind that the early dates have been achieved by the use of techniques such as TL, OSL and ESR which have rarely been applied in archaeological contexts in Southeast Asia (Roberts et al. 2005). Relying exclusively on the radiocarbon chronology, dates in the order of 40 000-47 000 BP have been obtained for occupation sites in both northern and southern Australia (Turney et al. 2001; O'Connor & Chappell 2003) and islands to the east of New Guinea requiring further water-crossings were also first settled by at least 40 000 BP (Leavesley & Chappell 2004). …