Two-million-year-old tooth links giant ape to modern orangutan

A two-million-year-old primate tooth from China links the largest ape to have walked the planet to modern orangutans.

The species - called Gigantopithecus blacki - has left behind few remains, with most of the fossils being teeth and jaws.

Some scientists believe “Giganto” could have been up to three metres tall, making it the largest known primate.

The species is thought to have gone extinct around 300,000 years ago, when the first humans started to appear.

Scientists were able to obtain genetic material - dental enamel proteins - from a broken molar with thick enamel discovered in Chuifeng Cave in China's Guangxi region near Vietnam.

The researchers concluded the tooth may have belonged to an adult female.

"Our data, for the first time, provides independent molecular evidence that the closest living relative of Gigantopithecus is the modern orangutan," said University of Copenhagen molecular anthropologist Frido Welker, lead author of the study published in the journal Nature.

“Not only do proteins survive, but they survive in sufficient quantities to enable resolving the evolutionary relationships between Giganto and extant great apes,” Welker added, referring to the group that includes orangutans, gorillas, bonobos and chimpanzees.

The orangutan and Gigantopithecus evolutionary lineages split about 12 million years ago, the researchers said.

"A long-unresolved issue comes to a solution," said paleoanthropologist and study co-author Wei Wang of Shandong University in China. "Its origin and evolution have puzzled paleoanthropologists for more than half a century."

It marked the first time that genetic material this old has been recovered from a fossil found in a warm, humid environment - conditions usually inhospitable to such preservation.

The researchers expressed hope the same technique can be used on other fossils, perhaps including species in the human evolutionary lineage.

Wang said Giganto may have had an orangutan-like appearance and most likely was a ground-dweller, unlike orangutans, which spend most of their time in trees.

It likely had a plant-based diet, perhaps eating sweet foods like fruit in forested environments, judging from the cavities seen in its teeth, Wang said.

Giganto appeared roughly two million years ago and went extinct about 300,000 years ago for reasons not fully understood. Wang said environmental and climate changes may be to blame.

Humans - or Homo sapiens - first appeared about 300,000 years ago in Africa, only later reaching Southeast Asia, meaning it is unlikely the two species met. Wang saw no evidence of other now-extinct human species playing a role in the Giganto's demise.