A mysterious partial skull unearthed in Papua New Guinea in 1929 — that once was thought to belong to an extinct human species — now turns out to have another unique distinction. Scientists believe it belongs to the oldest-known human tsunami victim.

Researchers said on Wednesday that new examinations of the sediments where the 6,000-year-old skull was found detected hallmarks of a tsunami, with a composition remarkably similar to the remnants of a deadly 1998 tsunami that lashed the same area.

The skull was discovered near the town of Aitape, about 7 miles (12 km) inland from Papua New Guinea's northern coast. It is one of the earliest human remains from the island of New Guinea, and initially was mistaken for a species called Homo erectus that died out about 140,000 years ago. Later scientific dating revealed it was actually 6,000 years old.