More than fifty headless skeletons have been unearthed in one of the oldest Pacific Islander cemeteries in the world.

The individuals were members of a socially complex society, traveling between islands hundreds of miles away, a new study suggests.

The finding could solve a long-held debate over whether the Lapita people, thought to be ancestors of the Polynesians, were isolated on individual islands or interacted with other distant Lapita tribes to find marriage partners, exchange information and maintain social ties.