Reconstruction of the late first millennium AD harbor site of Sembiran and analysis of its tradeware

The site of Sembiran on the northern coast of Bali was an important trading harbor with demonstrated intensive links to the Indian subcontinent, the Western Indian Ocean, and Mainland Southeast Asia between the second century BC and the second century AD. Using a combination of excavation and geophysical survey, we have newly mapped a dense network of subsurface structures, which we interpret to be foundations for harbor infrastructure dated to the eighth to ninth centuries AD that were subsequently covered by shoreline aggradation. An assemblage of eighth to twelfth centuries AD Chinese tradeware in dated contexts from our excavations of these shoreline structures and additional trenches further inland suggests a renewal in trade activities at Sembiran, coinciding with the growth of Chinese maritime trade in Island Southeast Asia.

Ulbe Bosma, The Making of a Periphery. How Island Southeast Asia Became a Mass Exporter of Labor. New York: Columbia University Press, 2019. ISBN 9780231188524 and ISBN 9780231547901

Many books have been written about the incorporation of the Caribbean region, South Asia, Africa and Latin America into the global economy. Remarkably, few have dealt with Island Southeast Asia or Maritime Southeast Asia as a macro-region. For the Caribbean nations, it has been amply discussed how the legacies of the plantation economies consisted of meagre economic growth and massive unemployment. Conversely, scant attention has been given to the question how societies in Island Southeast Asia were turned into providers of cheap commodities and how this impacted their long-term development prospects. This silence is even more remarkable considering some striking parallels with Caribbean socio-economic trajectories. Today, emigration of millions is the fate of Island Southeast Asia, as it is for the Caribbean region. To break the silence and to invite further discussion I wrote The Making of a Periphery: How Island Southeast Asia Became a Mass Exporter. After reading the review by Dr Aguilar on this book in a previous issue of this journal, I felt that it could be worthwhile to highlight some of the main points of my argument about the peripheral integration of Island Southeast Asia in the global economy. I am grateful to the editors of the International Journal of Asian Studies for granting me the opportunity to do so.

Ancient genomes from the last three millennia support multiple human dispersals into Wallacea

Previous research indicates that the human genetic diversity found in Wallacea - islands in present-day Eastern Indonesia and Timor-Leste that were never part of the Sunda or Sahul continental shelves - has been shaped by complex interactions between migrating Austronesian farmers and indigenous hunter-gatherer communities. Here, we provide new insights into this region's demographic history based on genome-wide data from 16 ancient individuals (2600-250 yrs BP) from islands of the North Moluccas, Sulawesi, and East Nusa Tenggara. While the ancestry of individuals from the northern islands fit earlier views of contact between groups related to the Austronesian expansion and the first colonization of Sahul, the ancestry of individuals from the southern islands revealed additional contributions from Mainland Southeast Asia, which seems to predate the Austronesian admixture in the region. Admixture time estimates for the oldest individuals of Wallacea are closer to archaeological estimates for the Austronesian arrival into the region than are admixture time estimates for present-day groups. The decreasing trend in admixture times exhibited by younger individuals supports a scenario of multiple or continuous admixture involving Papuan- and Asian-related groups. Our results clarify previously debated times of admixture and suggest that the Neolithic dispersals into Island Southeast Asia are associated with the spread of multiple genetic ancestries.

A rejoinder

In his response to my review of his book, Ulbe Bosma reiterates that high demographic growth and the consequent abundance of surplus labor as well as local systems of labor control were important factors in the peripheralization of Island Southeast Asia. Colonialism itself, he argues, is not responsible for the making of a periphery.

The first quantitative assessment of radiocarbon chronologies for initial pottery in Island Southeast Asia supports multi-directional Neolithic dispersal

Neolithization, or the Holocene demographic expansion of farming populations, accounts for significant changes in human and animal biology, artifacts, languages, and cultures across the earth. For Island Southeast Asia, the orthodox Out of Taiwan hypothesis proposes that Neolithic expansion originated from Taiwan with populations moving south into Island Southeast Asia, while the Western Route Migration hypothesis suggests the earliest farming populations entered from Mainland Southeast Asia in the west. These hypotheses are also linked to competing explanations of the Austronesian expansion, one of the most significant population dispersals in the ancient world that influenced human and environmental diversity from Madagascar to Easter Island and Hawai‘i to New Zealand. The fundamental archaeological test of the Out of Taiwan and Western Route Migration hypotheses is the geographic and chronological distribution of initial pottery assemblages, but these data have never been quantitatively analyzed. Using radiocarbon determinations from 20 archaeological sites, we present a Bayesian chronological analysis of initial pottery deposition in Island Southeast Asia and western Near Oceania. Both site-scale and island-scale Bayesian models were produced in Oxcal using radiocarbon determinations that are most confidently associated with selected target events. Our results indicate multi-directional Neolithic dispersal in Island Southeast Asia, with the earliest pottery contemporaneously deposited in western Borneo and the northern Philippines. This work supports emerging research that identifies separate processes of biological, linguistic, and material culture change in Island Southeast Asia.

Multiple migrations to the Philippines during the last 50,000 years

Island Southeast Asia has recently produced several surprises regarding human history, but the region’s complex demography remains poorly understood. Here, we report ∼2.3 million genotypes from 1,028 individuals representing 115 indigenous Philippine populations and genome-sequence data from two ∼8,000-y-old individuals from Liangdao in the Taiwan Strait. We show that the Philippine islands were populated by at least five waves of human migration: initially by Northern and Southern Negritos (distantly related to Australian and Papuan groups), followed by Manobo, Sama, Papuan, and Cordilleran-related populations. The ancestors of Cordillerans diverged from indigenous peoples of Taiwan at least ∼8,000 y ago, prior to the arrival of paddy field rice agriculture in the Philippines ∼2,500 y ago, where some of their descendants remain to be the least admixed East Asian groups carrying an ancestry shared by all Austronesian-speaking populations. These observations contradict an exclusive “out-of-Taiwan” model of farming–language–people dispersal within the last four millennia for the Philippines and Island Southeast Asia. Sama-related ethnic groups of southwestern Philippines additionally experienced some minimal South Asian gene flow starting ∼1,000 y ago. Lastly, only a few lowlanders, accounting for <1% of all individuals, presented a low level of West Eurasian admixture, indicating a limited genetic legacy of Spanish colonization in the Philippines. Altogether, our findings reveal a multilayered history of the Philippines, which served as a crucial gateway for the movement of people that ultimately changed the genetic landscape of the Asia-Pacific region.