Coolest Archaeological Discoveries of 2015

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Mysterious 14,000-year-old leg bone may belong to archaic human species

Scientists say a fossilized femur belongs to an ancient human species thought to be long extinct by the time this person walked the Earth. That leg bone could revolutionize current concepts of human evolution if they're right.

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  Courtesy of Peter Schouten

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  Courtesy of Darren Curnoe, Ji Xueping & Getty Images

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A 14,000-year-old thigh bone may upend human history.
Unearthed in southwest China, this femur resembles those of an ancient species of humans thought to be long extinct by the Late Pleistocene, scientists say. The scientists compare the leg bone to ancient and modern human femurs in a paper published Thursday in the journal PLOS ONE, arguing that this specimen represents a population of ancient humans that lived surprisingly recently.
If they're right, this could dramatically change the way we see human history.

Today, our species, Homo sapiens, are the only humans to walk the Earth. But it hasn't always been that way. 

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At times, ancient human species, like Neanderthals, Denisovans, H. erectus, and H. habilis, overlapped. Some even intermingled with our own species, as Denisovan genes show up in some modern humans living today.

Scientists thought that the last time there was more than one species of human on Earth was tens of thousands of years ago. One of our closest cousins, Neanderthals, for example, are thought to have died out about 40,000 years ago.

"Until now, it was thought that archaic humans on mainland Asia had survived no later than around 100,000 years ago," study author Darren Curnoe tells the Monitor in an email. "So, to find a human bone that resembles very ancient humans that is only around 14,000 years old is a real surprise."

"Now, it is only one bone, so we need to be a bit careful," Dr. Curnoe says. But if it does represent these ancient humans, "there must also have been overlap in time between archaic and modern humans for tens of thousands of years in Southwest China."

David Begun, a paleoanthropologist at the University of Toronto who is not affiliated with the study, tells the Monitor in an interview, "I'm not convinced."

"To me, it's just a Late Pleistocene, Early Holocene population that just looks a little bit different, that really doesn't have anything especially archaic about it," Dr. Begun says. "I certainly don't buy the argument that it is some kind of holdover from an Early Pleistocene, early Homo lineage, pre-Neanderthal or something like that. I'm not convinced by the evidence at all."

So what was Curnoe and his colleagues' evidence in the first place?

The scientists analyzed the femur by measuring and comparing physical features on the bone with both ancient and modern specimens.

Discovered among other fossils in Maludong, also known as Red Deer Cave, the femur "is very small; the shaft is narrow, with the outer layer of the shaft (or cortex) very thin; the walls of the shaft are reinforced (or buttressed) in areas of high strain; the femur neck is long; and the place of muscle attachment for the primary flexor muscle of the hip (the lesser trochanter) is very large and faces strongly backwards," Curnoe says.

By looking at measurements and traits of the bone, he says, "we found a clear association between the femur and the bones of the earliest members of the human genus Homo."

But Begun says the leg bone is too fragmentary to say all that. "It lacks most of what you would want to have in a femur to really say something about it," he says. "You'd want to have the head of the femur, the hip joint itself, and that's not here. It only preserves about a third of the length of the femur." 

The specimen also shows a lot of damage, Begun says. "Because of how fragmentary the specimen is and how damaged it is, I'm not convinced that the measurements really tell us much."

This isn't the first specimen from Maludong the team has described and named as a member of an ancient human species. In 2012, they published a paper on skulls found at the same site, suggesting the same thing – that these fossils represent a surprising population of ancient humans.

To survive so recently, this group of people would have likely been an isolated population. 

The region where the bones were found is unique, Curnoe explains. Tectonic uplift created the Qinghai-Tibetan Plateau and the area is also quite tropical.

So, Curnoe says, "The Maludong femur might therefore represent a relic, tropically adapted, archaic population that survived relatively late in this biogeographically complex, highly diverse and largely isolated region."

The Maludong specimen isn't the first that scientists have claimed is more recent evidence of ancient humans. Homo florensiensis, nicknamed "Hobbit" for its short stature, was found to have lived on the Island of Flores in Indonesia as late as 17,000 years ago.

"Honestly, it's not the same kind of situation as we have in Flores," Begun says. "It's just not the same thing because the archaic signal, the primitive signal is just not very clearly developed."

"I could be wrong," Begun admits. "But frankly, I'm not convinced."

"Without the more diagnostic parts of the bone, like the head of the femur and a complete neck and more of the shaft," he says, "it's just very very difficult to say anything about a specimen like that."

But Curnoe is unfazed by such a reaction. "Our work is bound to receive a mixed reaction because for some of our colleagues the idea that archaic humans could have survived until the end of the Ice Age in East Asia will be difficult to accept," he says. "There is simply no convincing some, regardless of what we might have found."

Pointing it out: Siloam Springs museum displays local Indian artifacts

Pointing it out: Siloam Springs museum displays local Indian artifacts

Siloam Springs Museum displays local Indian artifacts

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Artifacts collected locally tell archaeologists the area of the Illinois River valley and today's Northwest Arkansas were used by Caddo Indians, says Don Warden, director of the Siloam Springs Museum. The first European contact with Caddoan people was recorded in south Arkansas, Louisiana and Texas, he says, but the collection of Roy Chesney (1886-1957) supports the Northwest Arkansas connection.
The museum is offering a temporary exhibit, "Prehistory of Arkansas," featuring the collection of Chesney. Chesney grew up on a farm in the Siloam Springs area and worked in insurance and real estate. But his hobby was collecting "points" -- which probably began more than 100 years ago, Warden says.

FAQ
‘Prehistory of Arkansas’
WHEN — 10 a.m.-5 p.m. Tuesday to Saturday
WHERE — Siloam Springs Museum, 112 N. Maxwell St.
COST — Free
INFO — 524-4011
BONUS — George Sabo, director of the Arkansas Archeological Survey, will speak about Arkansas Indians at 2 p.m. Saturday.

"Points" lumps together several common artifacts -- arrowhead points, spear points, darts -- "projectile points," Warden says. Research over the years enabled archaeologists to identify the type of the point, by its shape and base point, as well as when it was made and from what culture it came.
"Crossroads From the Past," a panel exhibit from the Arkansas Humanities Council, gives an overview of Arkansas Indians from prehistory to history. The panels will be on display through Dec. 19, Warden says.
Points from many different tribes have been found by many people throughout the valley of the Illinois River, which runs just a few miles east of Siloam Springs. The Caddo developed farmsteads in the valley. In the 18th century, Osage supposedly hunted the hills, Warden says. Cherokee migrated to the area beginning about 1800.
In addition to the exhibit, the museum presents George Sabo, director of the Arkansas Archeological Survey, speaking about Arkansas Indians at 2 p.m. Saturday. He also will identify points and other stone tools brought by visitors.

Scientist have discovered new clues about the earliest known Americans

Human groups foraged near the bottom of South America between at least 18,500 and 14,500 years ago, researchers say.
Their new discoveries challenge a popular view in archaeology that people entered South America no earlier than 15,000 years ago.
Excavations in southern Chile indicate that ancient human groups sporadically passed through that area over a 4,000-year stretch, say archaeologist Tom Dillehay of Vanderbilt University in Nashville and colleagues.
Discoveries near the previously explored Monte Verde site add to evidence that the earliest New World settlers were not members of the Clovis culture, the investigators report November 18 in PLOS ONE.
Clovis people hunted big game with distinctive spearpoints and camped at sites with large hearths. Clovis sites date to as early as 13,390 years ago in what is now the United States and Mexico .
Long before that, ancient foragers intermittently stopped at Monte Verde, Dillehay suspects. Work at Monte Verde in the 1970s and 1980s yielded stone tools and other remains of a campsite from around 14,500 years ago. New finds include 39 stone artifacts, nine dating to between at least 18,500 and 17,000 years ago. About one-third of these stones consist of rock found outside the Monte Verde vicinity, either near the Pacific coast or further inland. Early South Americans acquired various types of tool-appropriate rock as they trekked across the landscape and may have traded for some types of rock with other human groups, Dillehay proposes.
Dillehay/New Archaeological Evidence for an Early Human Presence at Monte Verde, ChileThe oldest evidence of humans at Monte Verde comes from stone artifacts dating to between at least 18,500 and 17,000 years ago, including this piece of rock with sharpened edges for scraping or cutting.
Most of these intentionally modified rocks were used for scraping and cutting, the researchers say. A few circular stones were possibly flung at prey with slings. Artifacts also included sharp fragments of stone produced as by-products of toolmaking.
Four stone artifacts were found in soil dating to at least 25,000 years ago. But more evidence is needed to confirm that humans visited Monte Verde and other South American sites before 20,000 years ago , the scientists say.
Dillehay’s team also identified 12 soil sections containing ash from small fires, bits of burned wood and nine partial animal bones, five of which were burned or showed signs of heating. The estimated ages for the Monte Verde discoveries come from radiocarbon measures of burned material and soil analyses that estimate when artifacts were buried.
Archaeologists searching for further pre-Clovis sites will need to keep an eye out for simple tools and remnants of small hearths or campfires, Dillehay adds. Remains of Clovis sites, which typically feature separate areas for cooking, toolmaking and other activities, are easier to spot.
The discoveries at Monte Verde “point to a new kind of site that needs much more study” to understand when people first reached the Americas, remarks archaeologist Daniel Sandweiss of the University of Maine in Orono