Isotopic evidence for initial coastal colonization and subsequent diversification in the human occupation of Wallacea

Abstract

The resource-poor, isolated islands of Wallacea have been considered a major adaptive obstacle for hominins expanding into Australasia. Archaeological evidence has hinted that coastal adaptations in Homo sapiens enabled rapid island dispersal and settlement; however, there has been no means to directly test this proposition. Here, we apply stable carbon and oxygen isotope analysis to human and faunal tooth enamel from six Late Pleistocene to Holocene archaeological sites across Wallacea. The results demonstrate that the earliest human forager found in the region c. 42,000 years ago made significant use of coastal resources prior to subsequent niche diversification shown for later individuals. We argue that our data provides clear insights into the huge adaptive flexibility of our species, including its ability to specialize in the use of varied environments, particularly in comparison to other hominin species known from Island Southeast Asia.

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“…Maritime culture was present in the tropical island region of Wallacea over several millennia and provides the earliest evidence of open sea crossing capability for our species (Anderson, 2017;Balme, 2013). The region also contains some of the earliest direct evidence of marine resource exploitation in the world (O'Connor et al, 2011(O'Connor et al, , 2017aOno et al, 2010;Roberts et al, 2020;Szabó & Amesbury, 2011), and this maritime emphasis continued into the Metal-Age and historic periods (Ono et al, 2018a). By the terminal Pleistocene it appears that this insular region had developed inter-connectedness, as evidenced by analyses of obsidian artefacts recovered from sites on Alor and Timor (O'Connor et al, 2018;Reepmeyer et al, 2011Reepmeyer et al, , 2019, however, the extent of these networks is not well known.…”

A Latest Discovery of Austronesian Rock Art in the North Peninsula of Buano Island, Maluku

“…Based on the available data, we can temporarily agree that the communities associated with the oldest rock art culture in Indonesia, including Kalimantan and Sulawesi, are Australomelanesid communities. This Austromelanesid community is Homo Sapiens humans who have the criteria of Anatomically Modern Human who first reached the Southeast Asia region after leaving Africa and introgressing with other archaic human races that had already left Africa, that is Neanderthals and Denisovans (O'Connell & Allen, 2012;Roberts et al, 2020). The crossing of the migration paths that reached the Southeast Asian region is believed to have occurred in several waves, from the earliest initiation period around 60,000 to 70,000 years ago to the presence of evidence of archaeological remains characterized by the earliest Austronesian culture around 3,000 to 5,000 years ago (O'Connell & Allen, 2012).…”

“…Based on estimates of the oldest archaeological remains, geographically, the cultural time character of the Southern Maluku Islands were also generally separated from the Aru Islands area (Rutgrink, Visser, & van Welzen, 2018). Aru Islands is integrated into the Sahul Shelf, especially during the Last Glacial Maximum and also separated from the Southwest Maluku Region, which includes Wetar Island, Timor Island, Kisar Island, Leti Islands, to Babar Islands (O'Connell & Allen, 2007;Ray & Adams, 2001;Roberts et al, 2020;Sathiamurthy & Voris, 2006).…”

A different paradigm for the colonisation of Sahul

“…Additionally, Allen and O'Connell's hypothesis that people were forced to become less reliant on reef resources and broadened their diets in response to the lowering sea levels of the LGM is further supported by the recent isotope work of Roberts et al . (2020).…”