Scientists say they have unearthed evidence of the oldest-known case of decapitation in the New World, a 9,000-year-old skull found in Brazil.

The decapitated skull, along with hands that had also been cut off and placed over it, is 6,000 years older than the previously oldest confirmed case of ritual beheading in South America, researchers are reporting.

A suspected case of decapitation in North America — discovered in Florida — may be around 8,000 years old, they note.

Such ritualized decapitation was probably common in the New World, the scientists say, with heads of defeated enemies often displayed as trophies of war.

However, the researchers say, the Brazil skull was likely not an enemy trophy but rather a matter of ancestor worship; a number of prehistoric cults that remembered ancestors by honoring their skulls have been known worldwide.

The widespread practice of decapitation in the New World made an impression on the first European to arrive there, says study lead author André Strauss, an archaeologist at the Max Planck Institute for Evolutionary Anthropology in Germany.

"Few Amerindian habits impressed the European colonizers more than the taking and displaying of human body parts, especially when decapitation was involved," he says.

The skull uncovered in the latest discovery came from a tropical region of east-central Brazil called Lagoa Santa, Portuguese for "Holy Lake."

Other researchers had previously found the oldest evidence of rock art in South America in the region, dated to about 9,400 years ago.

The region has yielded evidence of human occupation, such as stone tools and animals bones, dating to around 12,000 years ago.

The skull was unearthed with the palms of the severed hands placed over it, facing in opposite directions.

The right hand, covering the left side of the skull's face, had its fingers pointing down to the chin, while the left hand was placed over the skull's right side with the fingers pointing upward.

Six cervical vertebrae just below the skull all bore V-shaped cut marks, the researchers reported in the journal PLOS ONE.

"Using cranial morphology and tooth wear, this individual was estimated to be a young adult male," Strauss said.

The configuration of the skull and hands suggests a sophisticated mortuary ritual practiced by early hunter-gatherers in the Americas, he said.

"The careful arrangement of the hands over the face is compatible with an important public display component in the ritual that could have worked to enhance social cohesion within the community," he explains.