Riddle of the Bones

She lies curled up as if only asleep, knees drawn to her chest, arms wrapped around them, tucked snugly in a nook between the coral boulders. But this woman is long dead, and her bones are as white as the coral branches that have crept among them like tree roots. Around her, lying in other cavities in the sharp rock and covered by volcanic ash, are the resting places of more human bones, all arranged in different positions of repose. Bats wheel above on the wind, which rushes through the coconut palms and sets the blue tarpaulin covering the graves flapping - a humble covering for one of the most important archaeological finds the South Pacific has yet seen.

What has riveted archaeologists since the 2003 discovery of this ancient cemetery at Teouma, on the main island of Efate, is that it's not only the oldest burial ground ever found in the region but dates back around 3,000 years - to when people first arrived in this part of the world. Never before has such a large collection of skeletal remains from these early wanderers, known as the Lapita people, been found. Excavations by an international team working with the Vanuatu National Museum began last year, followed by a second, more extensive dig, which finished last week. The finds of just two seasons' work, covering only a small part of the site, have left Pacific prehistory hunters unable to contain their glee. "It's the site we've all been looking for, the site we were hoping might exist," says Lisa Matisoo-Smith, a specialist in the study of ancient dna at the University of Auckland.

Last year's excavation yielded 13 skeletons, all of them headless. This find, the first of many mysteries, was followed by the discovery of three skulls resting on the chest of the skeleton of an elderly man. None of the skulls was his, and one contained a jawbone from another skull, which hasn't been found. In the past few weeks, another 10 individuals have been found, interred in a range of unusual positions - some lying on their side, others with their legs apart or face down, a fate sometimes associated in ancient burials with those guilty of awful crimes. One female was found laid carefully on her back, with all her vertebrae in place but her ribs and one foot missing; another had its feet resting on a coral shelf. These skeletons too were headless; some had had their clavicles removed as well. Teeth sprinkled around the top of the spines suggest that the skulls were dug up at least a year after the dead were buried, by which time the teeth would have come loose. While clavicles and forearm bones are known to have been favored as tools, the fate of the skulls, and the burial positions, are curious enough to ensure that "people will be arguing about this for the next 100 years," says Matthew Spriggs, professor of archaeology at the Australian National University.

More clues, and more questions, have come in recent weeks, with the discovery of a pot containing a skull - another enigma in a region with no record of similar mortuary rituals. It all adds up not only to the most exciting site Spriggs has worked on in 30 years of Pacific fieldwork, "but one of the weirdest, too. Every day we're scratching our heads, wondering what this is. Every day is like a new chapter in a book."

Many of Vanuatu's 83 islands are hard to reach and harder to get around, so it was a piece of astonishing luck that Teouma is only a short drive from Vanuatu's capital, Port Vila. It was another stroke of luck that the cemetery was discovered at all. After a bulldozer collecting soil for a prawn farm in 2003 turned up some pottery, the driver thought one of the shards pretty and took it home, where he showed his new curio to a friend. Thankfully for anyone interested in learning when and how the South Pacific was first settled, that friend happened not only to be a field worker for Vanuatu's Cultural Centre, but a recent graduate of an archaeological training course. As soon as he saw the pottery, he knew what it was.