Earlier arrival of stone tools on Flores

A new paper is pushing back the time of initial occupation of Flores by hominins to at least 1.0 million years ago. Adam Brumm and colleagues (2010) are reporting that they've found stone tools in a site from the Soa Basin of Flores, the same geological region as the previous site of Mata Menge.

The Wolo Sege excavation yielded no faunal remains, but 45 in situ stone artefacts were recovered from the conglomerate and two fine-grained metavolcanic flakes were excavated from the lower tuffaceous siltstone layer ~1520?cm above the Ola Kile Formation (Fig. 3e, f). A single volcanic flake was also recovered from the upper overbank deposit during extraction of sediment for dating. The Wolo Sege stone artefacts are predominantly small and morphologically undifferentiated flakes struck from cobbles by direct hard-hammer percussion (Fig. 3; see also Supplementary Fig. 2), but include a bifacially and centripetally worked radial core, similar to those characteristic of the Mata Menge assemblage of stone artefacts.

The radial core is not illustrated, but several of the flakes are figured in the paper. The conglomerate in question is overlain by a layer with a minimum date of 1.02 million years.

A date of 880,000 years ago for human occupation made for a convenient explanation of faunal turnover on the island, which happened around that time. The turnover included the extinction of the small pygmy stegodont species Stegodon sondaari, which was replaced in later faunal assemblages by the Java-derived Stegodon florensis. It also included the extinction of giant tortoises.

This suggests that the non-selective, mass death of S.?sondaari and giant tortoise, associated with stratigraphic evidence for a major volcanic eruption at Tangi Talo ~0.9?Myr ago10, could represent a localized or regional extinction, and that the faunal turnover may have been a result of climate change, volcanic activity or some other natural process or event (Fig. 5).

I discussed this with my graduate seminar yesterday. The long persistence of this toolmaking culture, in what must have been a rather small human population, is weighing on my mind. Were there recurrent contacts from Java, keeping the population going? How dependent were these people on their tools?

Hominin predators can lead to unstable dynamics -- most predators will undergo predator-prey cycles, but humans can switch to other resources and continue to press a small prey species to extinction. The long persistence of tasty animals on Flores in the presence of hominins suggests that the subsistence practices of these hominins were different in some ways from later humans.

This finding doesn't really help us to resolve the issues of the later Flores record, including the relationships of the skeletal individuals with other hominins. There's been some press about the hobbits lately, but it's all paleoanthropological tree-marking -- except for the news that they'll be reopening excavations at Liang Bua.

References:

Brumm A, Jensen GM, van den Bergh GD, Morwood MJ, Kurniawan I, Aziz F, Storey M. 2010. Hominins on Flores, Indonesia, by one million years ago. Nature (advance online) doi:10.1038/nature08844