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.”

Laser Scans Detect Hidden Buildings and Tunnels Beneath Alcatraz Prison

iStock.com/f8grapher
iStock.com/f8grapher

Isolated in the San Francisco Bay and surrounded by steep cliff faces, Alcatraz Federal Penitentiary seemed like the most secure place to keep dangerous criminals in the mid-20th century. But it's recently come to light that every inmate on Alcatraz Island lived above a series of potential escape routes that predated the prison's construction, the San Francisco Chronicle reports.

In a new study published in the journal Near Surface Geophysics, archaeologists reported their discovery of structures and artifacts beneath the Alcatraz prison yard, including underground buildings, tunnels, and ammunition magazines. Guided by historical maps, documents, and photographs, they used laser scanning technology and ground-penetrating radar to locate the subterranean fortress close to the surface.

The site dates back to the mid-19th century, when Alcatraz Island was used for military purposes. The same natural features that would later make Alcatraz an appealing prison also made it an ideal coastal fortification. Enough brick buildings were built there to house 200 soldiers and enough food was shipped in to feed them for four months.

But the fortification wasn't used for its original purpose for very long. It was transformed into the West Coast's official military prison during the Civil War, and in the 1930s, the government turned it into a federal prison. Instead of tearing down the forts and tunnels leftover from its military days, workers left them intact and built over them to save money. Archaeologists plan to investigate the underground structures further without disturbing the historic site.

Alcatraz Prison closed in 1963, so the underground tunnels no longer pose a security problem. Today the island is part of the U.S. National Park Service and is a popular tourist attraction.

[h/t San Fransisco Chronicle]

The Site Where Julius Caesar Was Assassinated Will Open to the Public in 2021

iStock.com/Largo di Torre Argentina
iStock.com/Largo di Torre Argentina

Besides being a sanctuary for stray cats, Largo di Torre Argentina in Rome is best known as the place where Julius Caesar was stabbed 22 times by assassins in 44 BCE. As the city's oldest open-air square, the spot is an important piece of Roman history, but it's fallen into disrepair. Now, Condé Nast Traveler reports that Largo di Torre Argentina will reopen to the public following a $1.1 million restoration project.

The site includes four ancient temples, a medieval brick tower, and the ruins of the senate house where Caesar was murdered. About 20 feet below street level, it was excavated under the rule of Benito Mussolini in the 1920s, and has remained largely closed to the public since. Today, Largo di Torre Argentina is overgrown and accessible only to the feral cats that live there.

On Monday, February 25, Rome mayor Virginia Raggi announced that Largo di Torre Argentina will reopen in the second half of 2021. To get the site ready for the public, the city will add restrooms, install lights, and build walkways that allow visitors to explore the area. Stone ruins, some of which are stacked into piles, will be secured, and artifacts currently sitting in storage will be moved to a museum. The one area the project will avoid is the corner where the cat sanctuary is located.

Rome, of course, is filled with ancient ruins—some that residents weren't even aware of until recently. In 2014, a 2000-year-old Roman road was unearthed during the construction of a McDonald's.

[h/t Condé Nast Traveler]

SECTIONS

arrow
LIVE SMARTER