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.”

A WWII Navy Submarine, Lost for 75 Years, Has Been Discovered Off the Coast of Japan

MR1805/iStock via Getty Images
MR1805/iStock via Getty Images

The U.S. Navy lost 52 submarines during World War II, many of which are still missing today. But as The New York Times reports, the wreck of the U.S.S. Grayback—a submarine that disappeared along with its 80-person crew in 1944—has been found off the coast of Okinawa, Japan.

On January 28, 1944, the Grayback departed from Pearl Harbor for its 10th combat patrol. It missed its scheduled return date that spring, and after weeks of failing to locate the vessel, the Navy declared it was likely lost.

Immediately following World War II, the U.S. military studied Japanese war records in search of clues that might lead them to their missing ships. One recording clearly states the Grayback was brought down by a bomb dropped by an Japanese aircraft, and it even gives the longitude and latitude of the attack. But due to a poor translation of the audio, the Navy went looking for the sub 100 miles away from its actual resting place.

Seventy-five years later, the submarine's coordinates were finally uncovered in old Imperial Japanese Navy files.

A Japanese researcher named Yutaka Iwasaki noticed this error while looking at the World War II records of the Imperial Japanese Navy base at Sasebo. He was asked to review the files for the Lost 52 Project, an organization dedicated to finding lost World War II submarines. Using the newly uncovered information and an autonomous underwater vehicle, the team was able to locate the vessel at the bottom of the East China Sea near Okinawa.

Lost 52 doesn't hunt for submarine wrecks with plans to recover them. Rather, the goal of the project is "documenting and preserving the story of the Lost 52 WWII Submarines, leaving a foundation of knowledge for future generations." In the case of the Grayback, the site where it settled on the seafloor will be protected from any human interference.

[h/t The New York Times]

Swedish Divers Just Discovered Two Shipwrecks That Might Be Related to the Famous Vasa Warship

The Vasa shipwreck displayed in Sweden's Vasa Museum.
The Vasa shipwreck displayed in Sweden's Vasa Museum.
Christian Lundh, Flickr // CC BY-NC 2.0

In 1625, King Gustavus II Adolphus of Sweden commissioned shipbuilders to create the most beautiful, lethal flagship that ever existed, as a symbol of Sweden’s naval strength. Three years later, crowds gathered to watch the Vasa, named after Sweden’s royal house, set sail for the first time. But less than a mile into its maiden voyage, the poorly and hastily constructed warship sunk to the bottom of the Baltic Sea, where it remained until 1961 when it was salvaged and later transported to the Vasa Museum.

Now, the Guardian reports Swedish maritime archaeologists from Vrak—Museum of Wrecks have located two shipwrecks in the Swedish archipelago outside of Vaxholm that could be linked to the Vasa. This is because the shipwright responsible for the Vasa built three other ships, the Äpplet, the Kronan, and the Scepter (though, unlike their ill-fated sibling, they actually made it into battle).

“It was like swimming around the Vasa ship,” maritime archaeologist Jim Hansson said in a museum press release. They believe the first wreck they discovered may be the Äpplet, and the second wreck could be either the Kronan or the Scepter.

“We think that some of them were sunk in the area,” Patrik Hoglund, another Vrak archaeologist, told the Guardian. But these ships didn’t capsize because of shoddy engineering or even an enemy attack. Instead, experts believe the Swedish navy intentionally sunk them after they were decommissioned, so their wrecks would function as surprise spike strips to damage approaching enemy ships.

The divers brought back wood samples from the wrecks to send to a laboratory for testing. Once they know when and where the timber came from, they can cross-reference the data with Swedish archives to find out if it matches information from the Vasa.

Even if the warships do turn out to be the Vasa’s long-lost siblings, it’s unlikely that they’ll be salvaged and displayed alongside it, since the Baltic Sea’s brackish waters actually preserve them much better than a museum could.

Sweden isn’t the only nation that boasts a beautiful shipwreck or two—here are 10 other shipwrecks around the world that you can visit.

[h/t The Guardian]

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