A mysterious small human species coexisted with modern man in China until at least 10,500 years ago, scientists have announced, based on an analysis of an anomalous thigh bone found in a cave.
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The discovery brings the number of human species coexisting until very recently to three: us, this new one and the so-called hobbit (Homo floresiensis) that survived on the Indonesian island of Flores until at least 13,000 years ago.
To put this in perspective, around when saber-toothed tigers and mammoths were going extinct in the late Ice Age and agriculture was beginning to develop in the Levant, at least three types of humans were roaming the planet.
The thigh bone found in Red Deer Cave in Yunnan Province is about 14,000 years old and is substantially different from a modern man’s, Prof. Darren Curnoe of the University of New South Wales and Prof. Ji Xueping of the Yunnan Institute of Cultural Relics and Archaeology report in PLOS ONE. Other remains from the same mysterious species, found nearby, dates to 10,500 years ago.
The thigh bone is more similar to those possessed by Homo habilis and early Homo erectus, which predated man by some 1.5 million years, than to man itself.
Like habilis, the scientists say, the Maludong (Red Deer Cave) thigh bone is tiny. And like the "hobbit," this hominin was a half-pint, apparently weighing around 50 kilos.
“It has been estimated from their thigh bones that Homo habilis individuals had a body mass of around 30 to 60 kilograms and early Homo erectus about 50 to 70 kilograms,” Curnoe told Haaretz. “We can’t estimate stature from the Maludong bone because it’s not complete enough, but with a mass of around 50 kilograms, it was small by Ice Age [modern] human standards.”
So if its bone is nothing like ours and it was alive 14,000 years ago, why is it so hard to categorically conclude that different human species lived cheek by hairy jowl with us?
“While our results seem clear that the femur is likely to be from an archaic human, we need to be careful, as it is only one bone,” Curnoe says. “Still, if we take this single fossil as representative of the species in question, then there must have been extensive overlap in time between modern and archaic humans.”
We were not alone
Actually, the Red Deer Cave people had been discovered decades ago. Bones, including a partial skull, had been found at Longlin Cave in the Guangxi Zhuang region in 1979. The thigh bone at Maludong was found in 1989 and has sat in a museum in Yunnan ever since.
Eventually a study began on the remains, starting with the skull bits found at Longlin. Thus in 2012 Curnoe, Ji and their team announced the discovery of the mystery “deer people” at Maludong and in Longlin Cave in nearby Guangxi. Then the coprolites it hit the fan: Was it a new species of archaic human or some sort of hybrid?
Things began to clear up with the analysis of the thigh bone, which tilted the argument toward unknown premodern species.
“We published our findings on the skull bones first [in 2012] because we thought they’d be the most revealing, but we were amazed by our studies of the thigh bone, which showed it to be much more primitive than the skulls seem to be,” Ji says.
The team suspects the skull found in nearby Longlin is a hybrid between modern humans and an unknown archaic group – perhaps even the people represented by the Maludong thigh bone. “We believe that more than one human species existed in southwest China but need to discover more fossils to test it,” Ji told Haaretz.
One thing that’s sure is that the Red Cave Deerites didn’t look like us. They had flat short faces, no chin and archaic big teeth. Their skulls were thicker than ours but their brains had modern-looking frontal lobes, the team wrote in 2012.
As for age, the Longlin skull and bones were dated between 10,500 and 14,300 years old. The Maludong bones were recovered during excavations from a single layer dated between about 14,300 and 13,600 years old, according to radiocarbon analysis of charcoal, Curnoe says, adding: “It is unlikely to be any younger.”
They ate deer
Regarding the three-foot-tall hobbit, many had argued it was a modern human that underwent so-called island dwarfism, when large species evolve smaller bodies, or was malformed or diseased. Could that be the case here?
“We have examined the bone carefully including with a microscope and using CT-scan imaging. We have found no obvious signs of disease,” Curnoe says. “So, disease is unlikely to explain the unusual features of the bone. Besides, no disease we know of which leaves signs on the skeleton would explain the unusual features of the Maludong bones.”
Genetic analysis could shed light on what the deer people really were, but life isn’t that simple.
“Geneticists at the Kunming Institute of Zoology have already had one unsuccessful attempt at extracting DNA from the femur and other bones,” Curnoe explains. “Unfortunately, the femur shows signs of having being burnt and Maludong itself is in a tropical area, so it’s unlikely that any ancient human DNA would have survived.”
Regarding DNA analysis, Ji adds, “We have invited the top scientist in the field of ancient DNA to do testing.”
How might Asia have housed primitive humans so long and so late, while they disappeared from Europe tens of thousands of years earlier? The rise of the Tibetan plateau created unique conditions in southwest China that could have created a refuge for human diversity, Ji postulates.
He seems unafraid of possible links between the hobbit and Red Deer Cave man, noting that both indeed were small. “Dwarfish” stature might have been normal in some human species in southern subtropical-tropical areas, he suggests.
The hobbits and the Red Deer Cave people, whoever they were, are the last known hominins to coexist with us. When Neanderthals and Denisovans died out is a subject of controversy, but it seems to have been thousands or tens of thousands of years earlier. Some wonder if the Red Deer Cave people could be a hybrid with Denisovans, who like Neanderthals interbred with modern man.
While throwing theories around, could these diminutive Red Deer Cavites be related to the pint-size hobbits on Flores?
“Our studies show that the Maludong femur is unlikely to represent the same species as the Hobbit from Flores in Indonesia. The bones of [the hobbit] species have been studied in detail and are very unusual, and are also very distinct from the Maludong thigh bone,” Curnoe says.
“It is intriguing that they both show resemblances to very ancient species of humans. But in the case of the hobbit, it more closely resembles species like Australopithecus afarensis, whereas the Maludong specimen resembles early Homo erectus.”
The Red Deer Cave people are called that because the evidence shows they cooked and ate a lot of red deer in that cave.