The Gigantopithecus blacki, or G. blacki, a three-meter-tall primate weighing up to 300 kilograms that once roamed the Karst plains of southern China, died out between 295,000 to 215,000 years ago, earlier than modern human's arrival in this region, according to the study published in the journal Nature.
Since the 1950s, around 2,000 fossilized teeth and four jawbones of the giant ape have been excavated in the Guangxi Zhuang autonomous region. But nothing from the neck down or from the jaw up has ever been found until now.
"The story of G. blacki is an enigma in paleoanthropology," said the paper's co-lead author, Zhang Yingqi, from the Institute of Vertebrate Palaeontology and Palaeoanthropology of the Chinese Academy of Sciences.
In 2015, Zhang and his colleagues launched a massive investigation in which they conducted a blanket search among hills across Guangxi. They collected evidence from 22 cave sites — half containing G. blacki remains and another 11 of a similar age range where no G. blacki evidence was found.
In the follow-up work, the team used six dating techniques for the cave sediments and fossils. The 157 results revealed this species was on the brink of extinction between 295,000 and 215,000 years ago.
A primary dating technique used in the study measured the light-sensitive signals found in the burial sediments encasing the fossils.
The ages from these were consistent with direct dating results on fossils. Together with the results of other techniques, they built a comprehensive and reliable chronology for the extinction of G. blacki.
With further evidence from pollen, fauna and stable isotopes, the team reconstructed the history of the ape's extinction.
The giant flourished in thick forests between 2.3 million and 700,000 years ago, but in the subsequent 400,000 years, the environments turned more seasonal, so their preferred habitats became sparse with the non-woody plants expanding, which heralded G. blacki's demise.
Against such survival stress, orangutans adapted their size, behavior and habitat preferences. But how could such a mighty creature fail at a time when other primates survived?
The team analyzed the trace elements and dental micro-wear texture in the teeth of G. blacki and orangutans.
The result revealed that G. blacki relied on less nutritious, high-fiber backup food when its preferences, like fruits and flowers, were hard to find, thus lowering food diversity.
However, those picky eaters had a reduced foraging range, and thus dwindled in their populations. In comparison, dental analysis showed more agile adapters like orangutans managed to seek out more food sources and establish new ecological niches, said Zhang in a news conference.