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Peter Schmid and William Harcourt-Smith / Wits University
Peter Schmid and William Harcourt-Smith / Wits University

Homo Naledi's Bones Were Made For Walking … and Climbing

Peter Schmid and William Harcourt-Smith / Wits University
Peter Schmid and William Harcourt-Smith / Wits University

Its bones were made for walking—and for climbing, and possibly for tool making. That’s the latest insight to emerge from the ongoing analysis of Homo Naledi, our newest human relative, discovered in 2013 in the deep, nearly inaccessible Rising Star cave system in South Africa’s Cradle of Humankind. A pair of papers recently published in Nature Communications—one on the creature’s foot, and the other on the hand—paint a more detailed picture of these small-brained creatures.  

In the foot study, a team of researchers led by William Harcourt-Smith, a paleoanthropologist at Lehman College and a resident research assistant at the American Museum of Natural History, analyzed 107 bones from the foot of H. Naledi, including one nearly complete adult foot.

“The key finding is that this is a foot that is really, really human-like in most respects,” Harcourt-Smith told mental_floss. “However, in such a human-like foot, we did also find a couple of features that aren’t so human-like.”

He points to the creature’s slightly curved bones in its toes—a more primitive feature that may have been used to climb trees. It also seems to have had an arch that was quite low, which may have affected how it could have walked long distances on two legs, Harcourt-Smith says: “That in itself is quite interesting, because it points to how these animals were experimenting with walking upright. And, of course, bipedalism defines us as being human.”

A digital reconstruction of the H. Naledi foot. (a) Dorsal view. (b) Distal view of the cuneiforms and cuboid showing transverse arch reconstruction. (c) Medial view showing the moderate longitudinal arch. Image credit: Harcourt-Smith et al. in Nature Communications

In the hand study, a team lead by paleoanthropologist Tracy Kivell, of the University of Kent’s Skeletal Biology Research Centre, studied the near-complete hand (it’s missing one wrist bone known as a pisiform) of H. Naledi that was found with the bones still partially connected—an extraordinarily rare find. Some 150 hand bones were unearthed in the cave in all.

The 26 bones show a mix of characteristics that have never been seen before in any other hominin species, they say. The wrist bones have adaptive features that would’ve helped H. Naledi use tools (though none have been discovered) that are consistently found only in modern humans and Neanderthals. On the other hand, the finger bones are curved more than most australopiths—bipedal hominids like the 3.3-million-year-old Lucy—and very different from the straight fingers of humans and Neanderthals, which indicates the creature spent a good amount of time climbing.

The H. Naledi bones have yet to be dated, which means we don't know where they fit in among our hominid relatives. "Depending on how old (geologically) the H. naledi remains turn out to be, there will be important implications for interpreting the South African archaeological record, who made the various stone tools that have been found, and what anatomical adaptations were necessary to craft these implements," Kivell said in a statement sent to mental_floss.  

The hand of H. Naledi. (a) Palmar (left) and dorsal (right) views of the right hand bones, (b) found in situ in semi-articulation with the palm up and fingers flexed. The palmar surface of the metacarpals (Mc) and dorsal surface of the intermediate phalanges (IP) can be seen. Image credit: Kivell et al. in Nature Communications

When you put together the mostly modern foot and the modern-primitive hand with other features of the H. naledi body—especially the shoulder suited for climbing and a tiny skull that is decidedly un-human like in size—you get a picture of a creature that is utterly unlike anything else in the fossil record, Harcourt-Smith says. H. Naledi’s unique suite of characteristics “really speak to a unique experiment with being upright, with some part of the time spent being in the trees and some of the time walking around on the ground,” he says.

They’re not yet sure how the creature would have walked. “We haven’t come up with a really good model how it moved yet,” Harcourt-Smith says. “It’s a real conundrum. But I can tell you this: It would’ve spending most of its time walking upright. Its heel would’ve struck the ground the way ours does, and when it was walking it would’ve [looked] distinct from us—but not that much so.”

He continues, “What’s really interesting is that we always used to think with the genus Homo that one of the hallmarks of it was being a full upright, sort of obligate, 100 percent biped. But we now have a creature that we’ve assigned to Homo based on its feet and skull, and yet it’s not really walking upright 100 percent of the time. It raises as many questions as it answers about bipeds.”

Figuring out how H. naledi moved is one of the next big areas of inquiry for the foot researchers. “We really want to reconstruct the gait of this creature,” Harcourt-Smith says. “That means working with all of the teams and coming up with a really robust biomechanical evaluation of the whole. It’ll be a few years worth of work.”

They're also going to investigate the internal architecture, he says. “We’re going to be looking at the molecular structure, and that requires very high-resolution CT scanning.”

As for the hand, Kivell too will be peering inside. “We have done microCT scans of the hand bones and will next analyze the internal bony structure—trabecular and cortical bone—which can tell us more information about function and how the H. naledi hand was used,” she told mental_floss in an email.     

While the science continues, the scientists themselves seem to still be riding the high of the discovery of this unprecedentedly large assemblage of unique bones, and excited by what they can teach us about our evolutionary past.

“When I got down there, it was fossil heaven,” Harcourt-Smith says. “There were so many different things. You never get these sort of opportunities with this amount of stuff found so quickly, and it really was an extraordinary privilege to work on. It’s not normal to get this sort of treasure trove of material in one go. It’s new territory in some ways.”

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Stones, Bones, and Wrecks
Ice Age Artists Used Charcoal Over 10,000 Years to Create Europe's Oldest Cave Paintings
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C. Fritz/MC

Tiny bits of charcoal found in a cave in France are providing new clues into how our prehistoric ancestors lived some 35,000 years ago.

The samples were taken from the Chauvet Pont d'Arc Cave in southern France, whose wall paintings are the oldest in Europe and among the oldest in the world. Few people have ever been inside the cave, which was discovered only in 1994 and remains one of the greatest archaeological discoveries of all time—but some might recognize it from Werner Herzog's award-winning documentary Cave of Forgotten Dreams.

The results of the charcoal analysis, published today in the April issue of the journal Antiquity, enabled researchers to paint a picture of how humans created art in the Ice Age, as well as the bitter climactic conditions of that time.

Researchers collected 171 samples of charcoal from hearths and torch marks in the cave. Other bits of charcoal were found directly beneath the animal paintings, which have been preserved in incredible detail after being sealed off by a rockfall thousands of years ago.

A drawing of rhinos inside the Chauvet cave
C. Fritz/MC

The analysis revealed that all but one of the charcoal samples came from burnt pine trees; the remaining one came from buckthorn. That doesn't sound all that impressive until you consider that some of these drawings were created nearly 10,000 years apart, during two different Ice Age periods. Put differently, for millennia, humans chose to use the same material for the sole purpose of creating art.

Researchers concluded that while other types of wood could have been used, the artists who created these cave paintings continued to choose pine, likely due to the availability of fallen branches as well as its combustion properties. But more remarkably, researchers believe these early artists selected it because it was the perfect medium for their art, ideal "for the smudging and blending techniques used in cave paintings," according to the study.

Over the years, the paintings have been praised for their artistic merit and use of motion. As Herzog commented in Cave of Forgotten Dreams, one artist's rendering of a bison with eight legs suggested movement—"almost a form of proto-cinema."

These findings also reveal what the climate was like during that time, and it was anything but balmy. The researchers write:

"Pine is a pioneer taxon [group] with an affinity for mountainous environments and survived in refuges during the coldest periods of the last ice age. As such, it attests, first and foremost, to the harsh climatic conditions that prevailed during the various occupations of the cave."

To preserve the cave paintings, only researchers are allowed inside the Chauvet Cave. However, a replica of the cave was built in France's Ardèche region and remains open to tourists.

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Stones, Bones, and Wrecks
Researchers Uncover What's Believed to Be the Oldest Shipwreck in Lake Erie
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iStock

In the fall of 1829, a ship had departed from Put-in-Bay, Ohio, but failed to reach its final destination. Now, researchers believe they have finally found its remains, which would make it the oldest shipwreck ever recorded in Lake Erie, if their theory is confirmed.

Remote sensors detected the wreckage three years ago, and the National Museum of the Great Lakes in Toledo, Ohio, has been working to identify the ship ever since then, according to The Blade newspaper in Toledo. Experts believe they have narrowed down their search from 200 possible shipwrecks to three. The museum is now raising money via Indiegogo to fund an underwater survey and partial excavation of the ship.

Strong evidence suggests that the wreckage belongs to one particular schooner—a sailing vessel with at least two masts—that was built in Cleveland in 1821. It was named the Lake Serpent in reference to a carving of a sea serpent on its bowsprit, according to the museum. In the fall of 1829, it left from Put-in-Bay on South Bass Island in Lake Erie, where crews loaded limestone onto the ship. It's unknown what happened after that, but we do know that the ship never reached its final destination. Local newspapers reported that the bodies of the captain and other crew members washed ashore in Lorain County, located about 25 miles from Cleveland, the ship’s intended destination.

It’s a wonder that the shipwreck was even detected at all. Tom Kowalczk, director of remote sensing for the Cleveland Underwater Explorers, which has a partnership with the Toledo museum, nearly wrote off the wreckage as a “small, barely noticeable anomaly” when he first detected it in 2015.

“The target was so small it was almost dismissed as a natural artifact,” Kowalczk wrote in a discovery report. “We were looking for shipwrecks! Curiosity got the upper hand and the boat was turned for a second look.”

Museum officials hope this finding will reveal unknown details about the design of early 19th-century ships from that region. Shipwreck hunters continue their search for another schooner called Lexington, which sank in the 1840s.

[h/t The Blade]

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