THE INDONESIAN island of Flores, made famous following the discovery of early humans likened to “hobbits” because of their size, is once again in the news following the discovery of stone tools, writes DICK AHLSTROM
The find pushes back the arrival of early humans there to at least one million years ago, and may help explain known animal extinctions on the island.
Controversy continues over the discovery in 2004 of what was later named Homo floresiensis. Some palaeontologists maintain the diminutive early human, or "hominin", represents a distinct species, while others maintain these were ordinary hominins but with some underlying condition tending them towards dwarfism.
The discovery of partial skeletons and a full skull from nine of these individuals caused a frenzy of public and media attention. They were thought to have shared Flores with ordinary-sized early humans, Homo sapiens, and to have lived there as recently as 18,000 years ago.
Whatever the truth behind these claims, Flores has once again yielded up important archaeological information about the history of hominins on the island, details that challenge our understanding of this history.
The findings are detailed this morning in the journal Nature, which has published them electronically on its website ahead of print publication.
Early man was known to have inhabited the island at least as long as 800,000 years ago. This is known by using advanced techniques to date stone tools used by the Flores settlers.
These settlers have been blamed for the subsequent extinction of two animal species that lived on Flores, a form of pygmy elephant-like animal ( Stegodon sondaari) and a giant tortoise ( Geochelone). These animals were plentiful in the fossil record up until the arrival of hominins to Flores.
But now the discovery of 45 stone artefacts, originally dug out of two cattle yards during an archaeological survey in September 2005, overturns these assumptions.
The tools eroded out of soils at Wolo Sega, located about 100km east and south of the Liang Bua cave where the Homo floresiensisremains were found.
Argon laser-fusion testing at the dating laboratory at Roskilde University in Denmark showed these artefacts and more dug out of situ could confidently be dated back to at least one million years ago.
This immediately undermined assumptions about the arrival of hominins to the island wiping out the pygmy elephant and giant tortoise, the authors suggest.
This “faunal turnover” or species loss “was attributed to the arrival of this new predator”, they write.
The new finding, however, “suggests that the non-selective mass death of S sondaari and giant tortoise, associated with stratigraphic evidence for a major volcanic eruption . . . could represent a localised 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”.
The morphology of the tools at the Wolo Sege site match those found elsewhere in the general area of the Soa Basin, simple stone flakes struck from cobbles by "direct hard-hammer percussion", but also slightly more complex artefacts, the international team of authors from Australia, Denmark, the Netherlands and Indonesia add. The question remains, however: who were these early settlers and were they ancestors of the Homo sapiensor Homo floresiensispopulations on the island? This, unfortunately, may never be revealed.
These latest finds were located at the very base of the accessible geological deposits within the Soa Basin. Its base is a hard layer left by volcanic eruptions. These are simply too young to be able to bring the story further back into the past, the authors note.
"If hominins arrived significantly earlier than one million years ago, as primitive morphological traits of the late-Pleistocene endemic species Homo floresiensismay indicate, then the sedimentary formations of the Soa Basin may be too young to provide evidence for the initial arrival of hominins on Flores, which must therefore be sought in other parts of the island."
