Ancient Foot Bones Uncover Evidence of Coexistence Between Two Human Species

Bones arranged in the approximate anatomical position of the right foot

The ancient human foot bones have puzzled scientists since their discovery in 2009.

Johannes Haile-Selassie

The origins of a 3.4-million-year-old foot bone uncovered in Ethiopia may finally be elucidated, prompting a reevaluation of how various ancient human ancestors cohabited.

In 2009, Johannes Haile-Selassie and his team at Arizona State University unearthed eight hominin bones that previously constituted a right foot at a site known as Burtele in northeastern Ethiopia’s Afar region.

This discovery, dubbed Bartele’s foot, features opposable big toes akin to those of gorillas, indicating that any species could have had arboreal capabilities.

Another ancient human species, Australopithecus afarensis, was known to inhabit the vicinity, with the well-known fossil of Lucy—also discovered in the Afar region—but Bartele’s foot appeared to belong to a different species. “From the outset, we realized it was not part of Lucy’s lineage,” Haile Selassie states.

There were two primary hypotheses that intrigued Haile Selassie: whether the foot was associated with another species within the genus Australopithecus or perhaps an older, more primitive group known as Ardipithecus, which existed in Ethiopia more than a million years ago and also possessed opposable thumbs.

Meanwhile, in 2015, scientists announced the identification of a previously unknown hominid species, named Australopithecus deiremeda, after jaw and tooth remains were found in the same region. Initially, there was uncertainty about whether the enigmatic leg bone was part of A. deiremeda, as its age differed from that of the jaw and tooth remains.

However, in the subsequent year, researchers made a crucial discovery. The lower jaw of A. deiremeda was located within 300 meters of Bartele’s foot, and both sets of remains were dated to the same geological era. This led the research team to conclude that Bartele’s foot belonged to A. deiremeda.

Bartele’s foot (left) and bones shaped like a gorilla’s foot (right), similar to Australopithecus deiremeda

Johannes Haile-Selassie

In a separate part of the study, researchers analyzed Earth’s carbon isotopes. They found that A. deiremeda primarily consumed materials from trees and shrubs, while human teeth were more adapted for a diet rich in grasses than those of afarensis.

Haile Selassie noted that this finding suggests that both hominin species occupied the same ecological niche without competing for resources. He believes these groups could have coexisted harmoniously, engaging in separate activities. “They must have crossed paths and interacted within the same habitat, each doing their own thing,” he remarked. “While members of Australopithecus deiremeda may have spent time in trees, afarensis was likely wandering the adjacent grasslands.”

This revelation enhances our understanding of human evolution. “Historically, some have argued that only a single hominid species existed at any given time, with newer forms emerging eventually,” Haile Selassie explained. “We are now realizing that our evolutionary path was not straightforward. Multiple closely related hominid species coexisted at the same time, indicating that coexistence was a fundamental aspect of our ancestors’ lives.”

Carrie Mongul, a professor at Stony Brook University in New York, expressed enthusiasm about these developments. “Understanding more about the diversity of Pliocene hominins is truly exciting,” she stated. “This period, around 3 million years ago, was rich in evolutionary significance.”

Topics:

  • Human evolution/
  • Ancient humans

Source: www.newscientist.com

Who Was the First Person to Set Foot in the British Isles?

homo heidelbergensis The ancient banks of the River Thames in modern-day Swanscombe, England

Natural History Museum/Scientific Photography Library

This is an excerpt from Our Human Story, a newsletter focused on the advancements in archaeology. Subscribe to receive it directly to your inbox each month.

When contemplating regions that are challenging for human habitation, we often envision extreme environments: the Sahara Desert, the Arctic, and the peaks of the Himalayas. While the British Isles may not be as severe, they posed significant challenges for ancient inhabitants.

A recent study I came across in September examined some of the earliest signs of human presence in Britain. The occupations highlighted in this study date back over 700,000 years, which is relatively recent when considering the migration patterns of early humans out of Africa. For instance, these early adventurers reached Indonesia quite swiftly but took longer to make their way to England.

To put numbers to this timeline: Around six to seven million years ago, humans roamed Africa. The oldest widely acknowledged evidence of humans outside Africa comes from Dmanisi, Georgia, where Homo erectus remains were uncovered, dating back 1.8 million years. These ancient relatives seem to have broadened their migration paths, eventually reaching locations like Java, Indonesia.

Nevertheless, the earliest evidence of human populations in Britain emerges within the last million years, indicating a significant gap.

Some scientists suggest that hominins could have been outside Africa much earlier, hinting at an even larger delay. For instance, stone tools have been identified in China’s Xihoudu, dating to 2.43 million years ago, and artifacts from Shangcheng are dated to 2.12 million years ago. Over the last five years, I’ve documented findings of Jordanian tools believed to be over 2 million years old, as well as Indian artifacts thought to date back to 2.6 million years. While the validity of these claims remains contentious—debating whether these objects are actual human tools or merely stones shaped by natural forces—the number of discoveries is growing, and I won’t be surprised if more concrete evidence surfaces shortly.

Regardless, it seems that settling in Britain was a gradual process for our ancient ancestors.

Farewell, Clear Skies

Alternatively, perhaps early humans arrived, took one look at the environment, and decided against settling without leaving a trace. Although the UK’s climate is mild in terms of its lack of extreme heat or cold, its gloomy weather and frequent rains present unique challenges.

During discussions about the British climate with Nina Jablonski from Penn State University, he remarked that in the UK, “the harsher the weather, the lower the UV rays, and the higher the seasonality.” Essentially, it’s jarringly overcast. Unless you venture to polar regions, finding a place with less sunlight is quite rare.

This pattern persists even today, and there were even colder periods. Since the onset of the Pleistocene epoch 2.58 million years ago, the climate has fluctuated between icy ages and warmer interglacial phases. We’ve enjoyed an interglacial phase for the last 11,700 years, during which polar ice sheets expanded south, enveloping vast regions of Britain.

Historically, evidence of ancient humans predominantly comes from warmer interglacial phases, but that narrative has shifted recently.

Research has focused on excavations at Old Park, adjacent to Canterbury in southeast England. In the 1920s, this area was home to Fordwich Pit, a quarry that yielded numerous stone tools. Since 2020, Dr. Alastair Key from the University of Cambridge has led excavations in the region.

His team reported in 2022 about their initial findings, which included 112 artifacts from layers dated between 513,000 and 570,000 years old. My colleague Jason Arun Murguez noted at the time that these artifacts represented the oldest of their kind discovered in Britain and Europe.

Three years later, Key’s team extended the dig and uncovered even older layers containing stone tools, potentially dating hominins to between 773,000 and 607,000 years ago.

For reference, a warm interglacial period occurred around 715,000 to 675,000 years ago. Conditions turned colder before and after this span in the ensuing eras.

Additionally, the researchers found two more recent layers with artifacts dating back to 542,000 and 437,000 years ago, coinciding with the earlier glacial periods.

This indicates that hominins occupied Old Park multiple times, even during the harshest climatic moments.

Ancient footprints uncovered in Happisburgh, England

Simon Parfitt

Heading North

In a broader perspective, while Old Park isn’t the earliest evidence of humankind in the British Isles, it comes very close. The oldest known evidence, however, has unfortunately vanished.

In 2013, while exploring a beach in Happisburgh, eastern England, researchers stumbled across 49 footprints preserved in layers of silt exposed by erosion. Sadly, these footprints were washed away weeks later, but archaeologists documented them and verified they were between 850,000 and 950,000 years old.

Happisburgh has also yielded findings of stone tools exceeding 780,000 years in age, while nearby Pakefield boasts artifacts dating to approximately 700,000 years ago. In stark contrast, the oldest human remains were found in Boxgrove, southeast England, dating back merely 500,000 years.

Of course, the archaeological record remains incomplete, making these sites only representative samples. In 2023, Key and colleague Nick Ashton suggested that humans might have already been in northern Europe as early as 1.16 million years ago. With fresh evidence emerging from Old Park, this date might need reconsideration.

And herein lies the mystery: Who were the ancient humans capable of surviving the often brutal climate of Britain?

Although Homo erectus seems to have been the first to venture out of Africa, concrete evidence of their presence in Europe is limited. Tools dating back 1.4 million years have been unearthed in Korolevo, Ukraine, but no hominin remains were found. Similarly, I reported earlier this year on the discovery of fragments of facial bones from Spain, dating to between 1.1 to 1.4 million years ago, attributed tentatively to “Homo af. erectus.”

Northern Spain was also home to another species, referred to as Homo antecessor, identified from a cave that existed between 772,000 and 949,000 years ago.

The Boxgrove hominids, on the other hand, are thought to belong to a distinct species, Homo heidelbergensis. Their classification poses challenges; they likely thrived in Europe hundreds of thousands of years ago, yet clear archaeological sites specifically linked to them remain scarce.

How these species interrelated, along with later groups like us and Neanderthals, remains a mystery. Consequently, the identities of the early Britons are still shrouded in uncertainty, fittingly, considering the cloudy weather.

Topic:

Source: www.newscientist.com